Home Wehrlite xenoliths and petrogenetic implications, Hosséré Do Guessa volcano, Adamawa plateau, Cameroon
Article Open Access

Wehrlite xenoliths and petrogenetic implications, Hosséré Do Guessa volcano, Adamawa plateau, Cameroon

  • Oumarou Faarouk Nkouandou , Jacques-Marie Bardintzeff EMAIL logo , Zénab Nouraan Njankouo Ndassa , Aminatou Fagny Mefire and Adama Haman
Published/Copyright: October 17, 2022
Download Article (PDF)
Become an author with De Gruyter Brill
Submit Manuscript Author Information
Open Geosciences
From the journal Open Geosciences Volume 14 Issue 1

Abstract

Peridotite xenoliths of wehrlite composition, scarcely known in Adamawa plateau, Cameroon, were sampled by Mio-Pliocene basanites from Hosséré Do Guessa volcano. Their origins are discussed and elucidated trough petrography and mineral chemistry. Studied wehrlites exhibit poikilitic or protogranular textures and are composed of four main mantle phases (high Mg-olivine, augite, enstatite and Al-spinel). Petrographic and microprobe (Camebax SX100) chemical data (Fo90.8-91.4 olivine, Wo39.4-42.0 augite, En90.5-91.1 enstatite and Al-spinel) suggest a mantle origin for the Hosséré Do Guessa wehrlites. Hence, these rocks could not be considered cumulate. They have been equilibrated between 1,140 and 1,220°C, at pressures of 1.5–2.0 GPa, at 50–66 km deep, below the crust-mantle boundary. Wehrlites might result in reactions with carbonate/carbonatite melt, accompanying CO2 degassing and metasomatism by fluid phases. They suffered transpressional tectonics, during movement at Tertiary times of Pan-African strike-slip-faults, after solid-state tectonic relaxation.

Graphical abstract

Keywords: wehrlite; metasomatism; Hosséré Do Guessa; Adamawa plateau; Cameroon

1 Introduction

The Cameroon Volcanic Line (CVL) is a Y-shaped oceanic and continental tectono-magmatic megastructure. Numerous volcanoes and plutonic-volcanic ring complexes, dated from Cenozoic to Quaternary compose the N30°E-trending CVL s.s. and the N70°E-trending Adamawa plateau, intersecting at Tchabal Mbabo volcano [1]. The internal structure of the Adamawa sub-continental mantle is still debated according to different studies.

Seismic and gravity studies [2,3,4,5,6,7,8,9,10,11,12] evidence (1) a crustal uplift resulting of the upward migration of the lithosphere-asthenosphere boundary, (2) an abnormally hot upwelling upper mantle located at the depth of 70–90 km [13] and (3) two broad negative gravity anomalies (−80 to −100 and −120 mGal/cm), attributable to lithospheric and crustal (crust is locally only 20 km thick) thinning.

Petrographical and mineral chemistry studies of numerous peridotite xenoliths found in the basaltic lavas evidence that they should be considered as fragments of the sub-continental lithosphere [14]. Ultramafic mantle xenoliths were sampled by Mio-Pliocene basanite lavas and pyroclastite projections on their way to the surface [3,15,16,17,18]. In the whole Adamawa plateau, ultramafic xenoliths display a compositionally diverse suite (spinel lherzolite, garnet lherzolite, olivine websterite, harzburgite). Mineral compositions, textures and thermobarometric conditions (820–1,160°C, 0.8–2.5 GPa, corresponding to different sampling depths of those rocks) evidence compositional heterogeneity of ∼57-km-thick lithospheric mantle (from 26 to 83 km in depth) beneath the Adamawa plateau with limited asthenosphere uprise [17,18].

This article describes newly discovered wehrlite xenoliths. They occur in Hosséré Do Guessa volcano, close to Mazélé, in the northernmost region of Ngaoundéré. The study includes mineral chemistry of xenoliths compared to those of host rock and geothermobarometry.

2 Geological setting

Hosséré Do Guessa volcano is located within Adamawa plateau (AP), a south-trending asymmetrical horst limited by a cliff in its northern side. The asymmetry could result from the difference between the north, where the plateau is elevated on a rather thin 23 km crust and the south with a classical ∼30–33 km crust [19]. The granulitic Pan-African (500–600 Ma) basement [20,21] is bounded to the north and to the south (Figure 1) by Pan-African N70° strike-slip faults [22,23]. These faults extend from Cameroon to Sudan along about 2,000 km [24] and crosscut the entire Adamawa lithosphere (crustal basement and upper mantle) down to depths greater than 190 km [6,13,19]. They have favored the ascent of alkaline magmas [22,25], which sampled fragments of sub-continental mantle xenoliths on their way to the surface. Geophysical studies carried out on the Adamawa plateau [6,7,8,9,10,11,12] show that a deflected and thin lithosphere with an effective elastic thickness of about 20 km [6]. Three major density contrasts were evidenced [6,19]: (1) the shallowest (4–15 km) boundary may be correlated to thrust structures and/or bottoms of sedimentary basins; (2) the 33–37 km boundary corresponds to the Moho; and (3) the 70–90 km boundary represents the lithosphere-asthenosphere boundary. From these different studies, a crust of 20–30 km thick and a lithosphere of 80–90 km thick seem to be evidenced in this region.

Figure 1 (a) Location of region of study in Africa continent, (b) main volcanic structures in Cameroon after [29]; red star shows the studied Hosséré Do Guessa volcano area in northern Ngaoundéré and (c) geological sketch map of Adamawa plateau (after [29]. (1) lateritic breastplate; (2) basalt of upper lava series; (3) trachyte and rhyolite; (4) basalt; (5) sedimentary rocks of southern Adamawa ditch, (a) metamorphic conglomerate and (b) conglomerate and arkose; (6) late panafricain granites; (7) schiste from Lom; (8) panafricain granites; (9) migmatite and gneiss; and (10) faults (a) with uprisde morphology and (b) with mylonite. (d) Location of Hosséré Do Guessa volcano near the village of Mazélé (yellow star).
Figure 1

(a) Location of region of study in Africa continent, (b) main volcanic structures in Cameroon after [29]; red star shows the studied Hosséré Do Guessa volcano area in northern Ngaoundéré and (c) geological sketch map of Adamawa plateau (after [29]. (1) lateritic breastplate; (2) basalt of upper lava series; (3) trachyte and rhyolite; (4) basalt; (5) sedimentary rocks of southern Adamawa ditch, (a) metamorphic conglomerate and (b) conglomerate and arkose; (6) late panafricain granites; (7) schiste from Lom; (8) panafricain granites; (9) migmatite and gneiss; and (10) faults (a) with uprisde morphology and (b) with mylonite. (d) Location of Hosséré Do Guessa volcano near the village of Mazélé (yellow star).

Previous petrologic studies on Adamawa mantle xenoliths [4,15,16,17,18,26] have shown that ultramafic xenoliths differ in nature and composition from each volcanic center to others. The present work is focused on the newly discovered ultramafic wehrlite xenoliths entrained by Mio-Pliocene basaltic lavas along the Pan-African cracks at the northernmost edge of Adamawa plateau in Hosséré Do Guessa volcano. Wehrlites were only scarcely described in Adamawa plateau [26].

3 Materials and methods

Petrographic studies have been carried out on about ten polished thin sections prepared from representative samples of ultramafic xenoliths at GEOPS laboratory, Université Paris-Saclay, France. Modal proportions of the four major mineral phases (olivine, orthopyroxene, clinopyroxene and spinel) have been estimated under scanning electron microscope (SEM), partly in Laboratory of Physics, University of Alexandru Ioan Cuza, Iasi, Romania, and partly in the GEOPS laboratory, Université Paris-Saclay, France.

Mineral compositions of host lavas and ultramafic xenoliths were analyzed on Camebax SX100 microprobe at Camparis, Université Paris-Sorbonne, France. The operating conditions were: olivine and clinopyroxene: 15 kV accelerating voltage and 40 nA beam current, 20 s counting time, except Si for olivine (10 s) and Ti for pyroxene (30 s); plagioclase: 15 kV, 10 nA, 10 s; titanomagnetite: 15 kV and 40 nA; Si, Ca, Ni: 10 s; Mn: 25 s; Cr: 15 s; Al: 30 s; and Ti, Fe, Mg: 40 s. Standards used were a combination of natural and synthetic minerals: diopside for Si, Ca and Mg; Fe2O3 for Fe; MnTiO3 for Ti and Mn; Cr2O3 for Cr; albite for Na; and orthoclase for K and Al. Data corrections were made using the PAP correction [27].

4 Results

4.1 Field work and petrography

4.1.1 Hosséré Do Guessa volcano

The basement of Adamawa Plateau is cut by a Panafrican fault network. Small volcanic centers were emplaced at fault crossings. These are also fissural flows without noticeable crater.

Hosséré Do Guessa volcano is located at N07°37′32″ and E13°41′06″. It culminates at 1,436 m, 17 m above the surrounding floor and presents a low elevation of rather rectangular form of 350 m × 260 m, elongated along the SW–NE direction (Figure 2a). Volume of volcanites ranges between 1.0 and 1.5 × 106 m3. Lava occur as dark grey loose blocks, which have a diameter of 1–1.5 m on the top of the hill and 20–50 cm in diameter on the flanks. They show a 1–3-mm-thick brown patina, and angular or rounded centimeter-size cavities (Figure 2b–e).

Figure 2 (a) View of the NE flank of Hosséré Do Guessa volcano. Peridotite xenoliths in host basanitic lava of Hosséré Do Guessa volcano. (b and c) rounded and (d and e) sub-angular shapes. Blue and red pens are 10 cm long.
Figure 2

(a) View of the NE flank of Hosséré Do Guessa volcano. Peridotite xenoliths in host basanitic lava of Hosséré Do Guessa volcano. (b and c) rounded and (d and e) sub-angular shapes. Blue and red pens are 10 cm long.

Basaltic host lava presents microlitic porphyritic texture (Figure 3a) that displays euhedral and subhedral olivine (15–18 vol%), clinopyroxene crystals (5–10 vol. %) sometimes with skeletal shape and oxides phenocrysts (<5 vol%). Plagioclase (20–25 vol%) and clinopyroxene (5 vol%) microliths are oriented along the flow foliation.

Figure 3 Photomicrographs of host basaltic lava (a) and xenoliths (b–e): wehrlite poikilitic texture (b and c), BSE images of representative peridotite samples showing: intimate contact between olivine and orthopyroxene (d), symplectite reaction with vermicular spinel between orthopyroxene crystals and exsolution (exsol) lamellas of orthopyroxene in clinopyroxene (e). cpx = clinopyroxene, ol = olivine, opx = orthopyroxene, sp = spinel.
Figure 3

Photomicrographs of host basaltic lava (a) and xenoliths (b–e): wehrlite poikilitic texture (b and c), BSE images of representative peridotite samples showing: intimate contact between olivine and orthopyroxene (d), symplectite reaction with vermicular spinel between orthopyroxene crystals and exsolution (exsol) lamellas of orthopyroxene in clinopyroxene (e). cpx = clinopyroxene, ol = olivine, opx = orthopyroxene, sp = spinel.

4.1.2 Peridotite xenoliths

Studied peridotite mantle xenoliths are collected in Mio-Pliocene basaltic lava flows of Hosséré Do Guessa volcano, 35 km at the northern edge of Ngaoundéré, near the so-called “Ngaoundéré cliff” (Figure 1b). The basement of this locality is delineated by numerous NW-SE shortening Pan-African faults [28,29], which may be related to the effect of the tectonic compression on the Adamawa plateau [29].

Yellowish, greenish and dark peridotite xenoliths have sizes of 8–15 cm and exhibit various shapes (angular, elongated or rounded shape, Figure 2). Contacts between xenoliths and host basaltic lavas are sharp (Figure 2c–e).

Modal compositions of xenoliths, estimated by microscopic observations and SEM images, are listed in Table 1. Their mineralogy is largely dominated by olivine (75–85%) and clinopyroxene (7–18%). The rest (5–8%) is composed of orthopyroxene and spinel.

Table 1

Sample location and modal mineral compositions (in volume%) of Hosséré Do Guessa wehrlites

Locality Sample number GPS coordinates Olivine Clinopyroxene Orthopyroxene Spinel
Mazélé TZ13 N: 07° 37′31.4″ 76 16 4 4
E: 13° 41′11.1″
Mazélé NZ-B1 N: 07° 37′31.9″ 77 18 4 1
E: 13° 41′07.2″
Mazélé TZ21 N: 07° 38′23.9″ 79 13 5 3
E: 13° 40′51.0″
Mazélé BM1 N: 07° 38′22.7″ 79 13 4 4
E: 13° 40′51.8″
Mazélé TZ110 N: 07° 38′25.6″ 75 17 5 3
E: 13° 40′47.8″
Mazélé MZ11 N: 07° 38′22.53″ 85 7 4 4
E: 13° 41′08.4″

According to the IUGS classification [30] (Figure 4), they are wehrlites, or lherzolites close to wehrlite-lherzolite boundary (samples TZ21 and TZ110). They present some similarities with wehrlites from Mt. Cameroon [31], West Eifel, Germany [32] and central Spain [33].

Figure 4 Ternary plot of olivine (Ol), orthopyroxene (Opx) and clinopyroxene (Cpx) modal compositions of the studied peridotite xenoliths after the IUGS nomenclature [30]. Data from Cameroon, Germany and Spain are added for comparison.
Figure 4

Ternary plot of olivine (Ol), orthopyroxene (Opx) and clinopyroxene (Cpx) modal compositions of the studied peridotite xenoliths after the IUGS nomenclature [30]. Data from Cameroon, Germany and Spain are added for comparison.

Textures are poikilitic (Figure 3b) or protogranular (Figure 3c–f) following [34], with some recrystallized olivine crystals.

Large (up to 7 mm) olivine crystals are weakly altered with thin micrometre-scale iddingsitized rims (Figure 3c). Smaller (200 µm) light-colored olivine crystals are included within large clinopyroxene crystals (Figure 3b) and exhibit no indications of deformation, or alteration.

Clinopyroxene crystals are large (500 µm to 5 mm) and constitute the poikilitic phase enclosing small olivine crystals (Figure 3b). Orthopyroxene crystals are interlocked with olivine as shown trough Back-Scattered Electron (BSE) images (Figure 3d). Spinel occurs as intercrystalline dark crystals (50 µm to 3 mm) (Figure 3b) or surrounds clinopyroxene (Figure 3d). Elongated (10–100 µm, rarely up to 0.5 mm long) exsolution lamellae of orthopyroxene within clinopyroxene occur seldom (Figure 3f). Dark brown spinel crystals exhibit vermicular shape. Symplectite textures of clustered pyroxene and spinel are frequent (Figure 3f).

4.2 Whole rock and mineral chemistry

4.2.1 Host lava

The lava (sample LTZ13) host of xenolith sample TZ13 was studied in detail [35,36]. Its whole-rock chemical composition is listed in Table 2. It is a typical basanite, rather silica-poor (43.26 wt% SiO2), but alkali rich (Na2O + K 2 O = 4.68 wt%, Ba = 538 ppm), with CIPW-normative nepheline (12.18 wt%). Its rather primitive character is shown by high Ni content (383 ppm). Data of mineral chemistry were previously published [35,36]. Additional data are listed in Table 3.

Table 2

Host lava (LTZ13) chemical composition and CIPW-normative composition calculated with Fe2O3/FeO = 0.15 [35,36]

LTZ13
Major elements (wt%)
SiO2 TiO2 Al2O3 Fe2O3 MnO MgO CaO Na2O K2O P2O5 LOI Sum
43.26 2.68 12.26 11.49 0.17 14.02 9.95 3.20 1.48 0.64 0.20 99.35
CIPW normative analysis (wt%)
Or Ab An Ne Dio Ol Mt Ilm Apt
8.75 4.58 14.72 12.18 24.41 24.95 1.98 5.09 1.48
Trace elements (ppm)
Be Rb Sr Cs Ba V Cr Co Ni Cu Y Zr
2.0 38 759 0.40 538 220 65.0 59.7 382.8 38 22.5 237
Hf Ta Th Nb Zn La Ce Pr Nd Sm Eu Gd
5.5 3.70 7.40 73 73 54.5 97 11.1 42 8.0 2.5 7.20
Tb Dy Ho Tm Yb Lu
0.980 5.04 0.91 0.28 1.80 0.24
Table 3

Representative microprobe compositions of major rock-forming minerals of Hosséré Do Guessa wehrlites host lava

Sample LTZ13
Mineral Olivine cpx pl mt
Type Phenocryst Xenocryst Phenocryst
SiO2 (wt%) 38.37 36.48 36.51 37.08 36.33 36.65 39.89 40.49 39.89 41.94 52.93 51.97 0.08 0.69
TiO2 5.12 21.89 21.79
Al2O3 9.32 29.04 29.42 1.75 1.58
Cr2O3 0.04 0.12 0.17
FeO 19.42 24.68 23.65 24.04 24.36 22.84 10.13 9.55 11.94 4.90 0.86 0.89 67.79 65.01
Fe2O3 4.54
MnO 0.40 0.48 0.54 0.52 0.60 0.42 0.15 0.12 0.21 0.11 0.90 1.03
MgO 40.04 37.10 37.44 37.62 36.66 38.71 49.66 49.41 47.31 10.54 3.54 3.41
NiO 0.23 0.14 0.09 0.24 0.13 0.19 0.40 0.37 0.40 0.00 0.00
CaO 0.25 0.49 0.46 0.49 0.45 0.30 0.10 0.12 0.15 22.14 11.27 12.03 0.07 0.70
Na2O 0.56 4.55 4.47
K2O 0.41 0.19
Sum 98.71 99.37 98.69 99.99 98.53 99.11 100.33 100.06 99.90 99.21 99.06 98.97 96.14 94.38
Si (apfu) 0.999 0.965 0.968 0.972 0.969 0.962 0.973 0.990 0.989 6.395 2.418 2.384 0.024 0.206
Ti 0.587 4.813 4.872
AlIV 1.605
AlVI 0.070
Cr 0.005 0.029 0.040
Fe3+ 0.521 5.527 5.081
Fe2+ 0.423 0.546 0.524 0.527 0.544 0.502 0.207 0.195 0.248 0.624 0.033 0.034 11.047 11.082
Mn 0.005 0.011 0.012 0.011 0.014 0.009 0.003 0.002 0.004 0.014 0.224 0.259
Mg 1.554 1.462 1.480 1.470 1.458 1.515 1.806 1.801 1.747 2.395 1.545 1.513
Ni 0.009 0.003 0.002 0.005 0.003 0.004 0.008 0.007 0.008
Ca 0.007 0.014 0.013 0.014 0.013 0.009 0.003 0.003 0.004 3.617 0.552 0.591 0.022 0.224
Na 0.166 0.403 0.397
K 0.024 0.011
Mg# 78.61 72.81 73.85 73.61 72.83 75.11 89.72 90.23 87.57 67.65
% Usp 61.49 64.51
Wo 50.44
En 33.40
Fs 16.17
An 56.30 59.12
Ab 41.26 39.77
Or 2.44 1.11

Structural formulas: olivine on the basis of 4 oxygen anions, clinopyroxene on the basis of 16 cations, plagioclase on the basis of 8 oxygen anions, Ti-magnetite on the basis of 32 oxygen anions.

Olivine phenocrysts have Fo71-79, decreasing from cores to rims and from phenocrysts to microcrysts, while olivine xenocrysts have high Fo contents (Fo88-90). CaO contents of olivine phenocrysts of host lava are high (0.25–0.55 wt% CaO) compared to low contents (0.10–0.15 wt%) in olivine xenocrysts. NiO contents of olivine phenocrysts are low (<0.2 wt%) whereas those of xenocrysts are higher (0.37–0.40 wt%).

Clinopyroxene phenocrysts are augite and diopside (Wo 43.2–48.4), some with fassaitic composition (Wo 50.4) as those described in Noun Plain, Cameroon [37]. TiO2 contents (2.7–5.1 wt%) and Al2O3 contents (from 6.6 to 9.3, until 12.4 wt%) are high. Mg# ratios (68–76) are in the range as olivine.

Oxide phenocrysts and microcrysts are Ti-magnetite (TiO2: 21.8–21.9 wt% and FeOt: 65.0–67.8 wt%). Cr2O3 contents are low (0.12–0.17 wt%), while MgO contents are fairly constant (3.4–3.5 wt%).

4.2.2 Wehrlite xenoliths

Representative microprobe analyses of olivine, orthopyroxene, clinopyroxene and spinel are listed in Tables 4–6.

Table 4

Representative microprobe compositions of olivine of Hosséré Do Guessa wehrlite and structural formulas on the basis of 4 oxygen anions

Sample TZ13
n0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
SiO2 (wt%) 41.16 41.12 40.77 40.36 40.77 40.81 40.63 40.92 40.78 40.87 40.66 41.12 40.61 40.78
FeO 8.52 8.39 8.52 8.86 8.80 8.70 8.76 8.73 8.35 8.68 8.75 8.51 8.64 8.86
MnO 0.20 0.11 0.14 0.14 0.06 0.16 0.19 0.18 0.17 0.20 0.18 0.17 0.12 0.17
MgO 50.51 50.32 50.75 50.28 50.46 50.15 50.15 50.11 50.13 50.32 50.61 50.36 50.44 50.30
CaO 0.03 0.03 0.04 0.06 0.05 0.02 0.05 0.08 0.03 0.04 0.06 0.06 0.06 0.03
NiO 0.36 0.48 0.43 0.44 0.37 0.24 0.42 0.46 0.45 0.34 0.36 0.36 0.37 0.41
Sum 100.78 100.45 100.65 100.14 100.51 100.08 100.20 100.48 99.91 100.45 100.62 100.58 100.24 100.55
Si (apfu) 0.996 0.998 0.989 0.987 0.991 0.995 0.991 0.995 0.996 0.994 0.988 0.997 0.990 0.992
Fe2+ 0.172 0.170 0.173 0.181 0.179 0.177 0.179 0.177 0.171 0.176 0.178 0.173 0.176 0.180
Mn 0.004 0.002 0.003 0.003 0.001 0.003 0.004 0.004 0.003 0.004 0.004 0.003 0.002 0.003
Mg 1.823 1.821 1.836 1.832 1.829 1.823 1.824 1.817 1.825 1.824 1.834 1.821 1.833 1.824
Ca 0.001 0.001 0.001 0.001 0.001 0.000 0.001 0.002 0.001 0.001 0.002 0.001 0.002 0.001
Ni 0.007 0.009 0.008 0.009 0.007 0.005 0.008 0.009 0.009 0.007 0.007 0.007 0.007 0.008
Fo% 91.17 91.35 91.26 90.88 91.03 90.98 90.90 90.93 91.29 91.00 91.00 91.18 91.12 90.85
Table 5

Representative microprobe compositions of clinopyroxene and orthopyroxene of Hosséré Do Guessa wehrlite and structural formulas on the basis of 16 cations

Sample TZ13
Mineral Clinopyroxene
n0 1 2 3 4 5 6 7 8 9 10 11 12
SiO2 (wt%) 50.79 51.19 51.16 50.82 51.06 51.89 51.44 51.62 50.77 51.77 52.15 50.70
TiO2 0.96 0.86 0.87 0.84 0.77 0.76 0.85 0.83 1.27 0.81 0.82 0.75
Al2O3 5.88 5.66 5.45 5.41 5.37 5.51 5.44 5.43 5.00 5.33 5.40 5.51
Cr2O3 0.95 0.98 0.90 0.98 0.95 0.95 0.90 0.99 0.89 0.94 0.94 0.94
FeO* 4.04 4.71 4.34 3.52 2.93 4.09 4.31 3.88 4.33 3.92 4.62 0.02
Fe2O3* 1.57 0.84 0.90 2.00 2.77 1.22 1.09 1.60 1.24 1.02 0.55 5.41
MnO 0.04 0.16 0.10 0.16 0.09 0.11 0.08 0.13 0.23 0.10 0.12 0.08
MgO 16.29 16.47 16.34 16.73 16.62 16.87 16.24 16.50 16.27 16.39 16.55 16.80
NiO 0.16
CaO 18.47 18.34 18.29 17.93 18.45 18.42 18.79 18.73 19.62 19.26 18.80 18.89
Na2O 1.04 0.92 1.07 1.09 1.18 1.05 1.05 1.09 0.68 1.02 1.03 1.06
Sum 100.03 100.13 99.42 99.48 100.19 100.87 100.19 100.80 100.30 100.56 100.98 100.32
Si (apfu) 7.396 7.448 7.485 7.429 7.416 7.477 7.478 7.457 7.407 7.491 7.513 7.311
Ti 0.105 0.094 0.096 0.092 0.084 0.082 0.093 0.090 0.139 0.088 0.089 0.082
AlIV 0.604 0.552 0.515 0.571 0.584 0.523 0.522 0.543 0.593 0.509 0.487 0.689
AlVI 0.406 0.419 0.424 0.362 0.336 0.412 0.410 0.382 0.267 0.401 0.430 0.247
Cr 0.109 0.113 0.104 0.113 0.109 0.108 0.103 0.113 0.103 0.107 0.107 0.108
Fe3+ 0.172 0.092 0.099 0.220 0.303 0.132 0.119 0.174 0.136 0.111 0.059 0.587
Fe2+ 0.492 0.573 0.531 0.430 0.356 0.492 0.524 0.469 0.529 0.474 0.556 0.002
Mn 0.005 0.020 0.012 0.020 0.011 0.013 0.010 0.016 0.028 0.012 0.015 0.010
Mg 3.535 3.571 3.563 3.645 3.598 3.623 3.518 3.552 3.538 3.535 3.554 3.611
Ni 0.019
Ca 2.882 2.859 2.867 2.809 2.871 2.844 2.927 2.899 3.067 2.986 2.902 2.919
Na 0.294 0.260 0.304 0.309 0.332 0.293 0.296 0.305 0.192 0.286 0.288 0.297
Mg# 84.19 84.31 84.97 84.86 84.53 85.30 84.55 84.68 84.18 85.81 85.23 85.96
Wo 40.67 40.19 40.54 39.43 40.22 40.03 41.23 40.78 42.03 41.96 40.96 40.94
En 49.89 50.20 50.37 51.17 50.40 50.99 49.57 49.96 48.47 49.66 50.15 50.65
Fs 9.44 9.62 9.08 9.41 9.38 8.98 9.20 9.26 9.50 8.38 8.90 8.41
Sample TZ13
Mineral Orthopyroxene
n0 13 14 15 16 17 18 19 20
SiO2 (wt%) 57.74 58.00 57.73 57.89 58.17 57.92 53.41 54.41
TiO2 0.00 0.00 0.00 0.00 0.00 0.00 0.30 0.32
Al2O3 1.28 0.76 0.84 0.84 0.72 0.74 4.58 4.37
Cr2O3 0.04 0.02 0.04 0.03 0.04 0.05 0.73 0.75
FeO* 5.27 5.22 5.08 4.09 5.12 5.06 4.84 6.49
Fe2O3* 0.45 0.14 0.32 1.45 0.53 0.57 4.01 1.98
MnO 0.29 0.19 0.19 0.18 0.12 0.11 0.13 0.09
MgO 35.11 35.39 35.31 35.90 35.67 35.47 30.70 30.59
NiO 0.10
CaO 0.46 0.50 0.47 0.54 0.51 0.47 1.45 1.38
Na2O 0.07 0.05 0.05 0.06 0.02 0.06 0.11 0.11
Sum 100.71 100.27 100.03 100.98 100.90 100.45 100.36 100.49
Si (apfu) 7.881 7.937 7.920 7.865 7.916 7.916 7.417 7.538
Ti 0.000 0.000 0.000 0.000 0.000 0.000 0.031 0.033
AlIV 0.119 0.063 0.080 0.135 0.084 0.084 0.583 0.462
AlVI 0.087 0.059 0.056 0.000 0.031 0.035 0.166 0.251
Cr 0.004 0.002 0.004 0.003 0.004 0.005 0.080 0.082
Fe3+ 0.046 0.015 0.033 0.148 0.054 0.059 0.419 0.206
Fe2+ 0.601 0.598 0.583 0.465 0.583 0.578 0.563 0.752
Mn 0.034 0.022 0.022 0.021 0.014 0.013 0.015 0.011
Mg 7.142 7.217 7.219 7.269 7.234 7.225 6.354 6.316
Ni 0.012 0.000
Ca 0.067 0.073 0.069 0.079 0.074 0.069 0.216 0.205
Na 0.019 0.013 0.013 0.016 0.005 0.016 0.030 0.029
Mg# 91.69 92.18 92.14 92.22 91.90 91.90 86.62 86.82
Wo 0.85 0.93 0.87 0.98 0.93 0.87 2.86 2.74
En 90.52 91.07 91.08 91.07 90.88 90.96 83.97 84.31
Fs 8.63 8.00 8.05 7.95 8.18 8.18 13.17 12.94

FeO* and Fe2O3* recalculated according to a total of 16 cations.

Table 6

Representative microprobe compositions of spinel and structural formula on the basis of 24 total cations

Sample TZ13
Mineral Spinel
n0 1 11 13
SiO2 (wt%) 0.92 0.25 0.21
TiO2 0.91 1.77 1.28
Al2O3 50.51 37.89 44.07
Cr2O3 10.15 21.17 15.49
FeOt 18.94 18.08 22.15
MgO 17.70 19.65 17.01
NiO 0.35 0.46 0.22
CaO 0.02 0.01 0.08
Na2O 0.03 0.01 0.01
Sum 99.53 99.29 100.52
Si (apfu) 0.197 0.055 0.046
Ti 0.147 0.296 0.211
Alt 12.786 9.947 11.397
Cr 1.724 3.728 2.687
Fe3+ 0.812 1.629 1.406
Fe2+ 2.590 1.738 2.658
Mg 5.667 6.525 5.565
Ni 0.061 0.082 0.039
Ca 0.005 0.003 0.018
Na 0.010 0.005 0.003
Mg# 68.63 78.96 67.67
Cr# 11.88 27.26 19.08
Fe3+# 5.30 10.65 9.08

Olivine varies in Fo between 90.8 and 91.4 (Table 4) and CaO contents are very low (<0.1 wt%). High NiO contents range between 0.24 and 0.48 wt%.

Clinopyroxene (Table 5) is augite (Figure 5) with Wo39.4–42.0 En48.5–51.2 Fs9.0–9.6. TiO2 (0.76–1.27 wt%) contents are fairly low and Al2O3 (5.00–5.88 wt%) contents are high. Cr2O3, contents range between 0.89 and 0.99 wt%. Na2O contents between 0.68 and 1.18 wt% are somewhat high for mantle pyroxene. Mg# (=Mg/Mg + Fe) are fairly constant, between 84.2 and 85.8. In TiO2 (wt%) in pyroxene versus Mg# in coexisting olivine diagram (Figure 6, according to [38]), wehrlite minerals plot higher than the lherzolite field. In the MgO versus Al2O3 diagram (Figure 7, after [39]), clinopyroxene compositions plot within the spinel peridotite field.

Figure 5 Pyroxene composition of Hosséré Do Guessa wehrlites and host lava in quadrilateral diagram after [40]. Thermometry between 500°C and 1,300°C according to [45] for P = 5 kbar (0.5 GPa).
Figure 5

Pyroxene composition of Hosséré Do Guessa wehrlites and host lava in quadrilateral diagram after [40]. Thermometry between 500°C and 1,300°C according to [45] for P = 5 kbar (0.5 GPa).

Figure 6 Mg# in Ol versus TiO2 in Cpx in Hosséré Do Guessa wehrlite following [38]. Dashed line with arrow indicates the mantle refertilization.
Figure 6

Mg# in Ol versus TiO2 in Cpx in Hosséré Do Guessa wehrlite following [38]. Dashed line with arrow indicates the mantle refertilization.

Figure 7 MgO versus Al2O3 for clinopyroxene of Hosséré Do Guessa wehrlites compared with other peridotites of Cameroon, plotted in the fields defined by ref. [39].
Figure 7

MgO versus Al2O3 for clinopyroxene of Hosséré Do Guessa wehrlites compared with other peridotites of Cameroon, plotted in the fields defined by ref. [39].

Orthopyroxene (Table 5) is enstatite (after [40]) with Wo0.8–1.0 En90.5–91.1 Fs7.9–8.6. Al2O3 contents (0.72–1.28 wt%) are low and fairly constant whereas Cr2O3 contents (0.02–0.05 wt%) are very low. Mg# ratios (91.7–92.2) are higher than in clinopyroxene and slightly higher than in olivine.

Spinel (Table 6) is Al-spinel after [41]. It shows some contrasted compositions, with varying Cr# (11.9–27.3) and Fe3+# (5.3–10.7). In Fo versus Cr# OSMA diagram (after [42], Figure 8), wehrlites plot in the mantle spinel array.

Figure 8 Fo (olivine) versus Cr# (spinel) diagram (after [42]). OSMA = olivine spinel mantle array. Data for peridotite xenoliths from Cameroon [18,31,75], São Tomé [76], Madagascar [77] and elsewhere in the world [42] are added for comparison.
Figure 8

Fo (olivine) versus Cr# (spinel) diagram (after [42]). OSMA = olivine spinel mantle array. Data for peridotite xenoliths from Cameroon [18,31,75], São Tomé [76], Madagascar [77] and elsewhere in the world [42] are added for comparison.

4.3 Thermobarometry

Equilibrium temperatures, pressures and depths of wehrlite from Hosséré Do Guessa volcano have been estimated through several currently available and appropriate thermobarometers based on different exchange mechanisms (Table 7, Figure 9). Crystal core compositions have been preferentially used for calculations.

Table 7

Temperature, pressure and depth estimations for Hosséré Do Guessa wehrlite

Sample/method TMOpx (°C) (n0 Opx) TMCpx (°C) (n0Cpx) TWOpx/Cpx (°C) (n0Cpx-n0-Opx) TBKNaOpx/Cpx (°C) (n0Cpx-n0-Opx) TBKCaOpx (°C) (n0Opx) TOWOl/Sp (°C) (n0Ol-n0Sp) TPCpx-Opx (°C) (n0Cpx-n0-Opx)
TZ13 899.9 (13) 1090.2 (1) 1091.0 (1–13) 754.6 (4–13) 751.8 (13) 1135.0 (1–1) 1172.0 (2–13)
TZ13 872.9 (14) 1219.2 (2) 1072.0 (2–13) 799.66 (5–13) 766.2 (14) 1137.0 (2–1) 1183.4 (4–13)
TZ13 874.2 (15) 1209.8 (3) 1092.0 (2–14) 767.2 (6–14) 756.1 (15) 1005.0 (3–1) 1124.5 (9–13)
TZ13 871.0 (16) 1183.1 (4) 1116.0 (4–14) 812.1 (7–16) 779.2 (16) 1152.0 (4–1) 1179.6 (4–16)
TZ13 850.2 (17) 1184.0 (5) 1100.0 (3–15) 802.4 (9–17) 768.7 (17) 1178.0 (5–1) 1125.2 (9–16)
TZ13 840.5 (18) 1189.0 (6) 1109.0 (5–15) 900.8 (10–18) 756.9 (18) 1160.0 (7–1) 1133.9 (12–19)
TZ13 1263.20 (19) 1154.5 (7) 1102.0 (6–16) 1194.8 (12–19) 1146.5 (20) 1087.0 (9–1) 1135.7 (12–20)
TZ13 1258.73 (20) 1162.2 (8) 1087.0 (1–17) 1191.2 (12–20) 1161.7 (19) 1089.0 (11–1)
TZ13 1176.63 (9) 1131 (12–19) 1178.0 (6–11)
TZ13 1210.65 (10) 1120 (12–20) 1223.2 (11–11)
TZ13 1180.49 (11) 1177.7 (6–13)
TZ13 1215.15 (12) 1197.9 (11–13)
PMOpx (GPa)/Depth (Km) PMCpx (GPa)/Depth (Km) PPCpx-Opx (GPa)/Depth (Km)
TZ13 0.16 (13)/5.28 0.58 (1)/19.14 2.02 (2–13)/66.66
TZ13 2.24 (14)/73.94 0.71 (2)/23.43 2.10 (4–13)/69.30
TZ13 2.50 (15)/82.50 0.90 (3)/29.80 1.65 (9–13)/54.45
TZ13 2.43 (16)/80.32 0.94 (4)/31.02 1.79 (4–16)/59.07
TZ13 2.58 (17)/85.01 0.79 (5)/26.20 1.41 (9–16)/46.53
TZ13 2.45 (18)/70.00 0.86 (6)/28.50 0.72 (12–19)/23.76
TZ13 0.34 (19)/11.01 0.90 (7)/29.60 0.7 (12–20)/23.1
TZ13 0.89 (20)/29.21 3.48 (8)/114.90
TZ13 0.90 (9)/29.60
TZ13 3.48 (10)/114.90
TZ13 3.04 (11)/100.30
TZ13 3.32 (12)/109.9

TMOpx: temperature calculation after [46] using orthopyroxene, TMCpx: using clinopyroxene, TW: temperature calculation after [47], TBK: temperature calculation after [48], TOW: temperature calculation after [49], TPCpx-Opx and PPCpx-Opx: temperature/pressure calculation after [50] using clinopyroxene and orthopyroxene, PMOpx and PMCpx: pressure calculation after [46] formula using clinopyroxene and orthopyroxene, GPa: gigapascal, n0: pyroxene, olivine and spinel analysis number as in Tables 4–6.

Figure 9 Equilibrium conditions of Hosséré Do Guessa wehrlites plotted in a temperature versus pressure (depth) diagram (adapted from [58]. Four values calculated between 3.04 and 3.48 GPa (Table 7) are not plotted in this diagram. Curves 1 and 2 are, respectively, the hydrous (0.4 wt% H2O) and anhydrous solidi [78].
Figure 9

Equilibrium conditions of Hosséré Do Guessa wehrlites plotted in a temperature versus pressure (depth) diagram (adapted from [58]. Four values calculated between 3.04 and 3.48 GPa (Table 7) are not plotted in this diagram. Curves 1 and 2 are, respectively, the hydrous (0.4 wt% H2O) and anhydrous solidi [78].

4.3.1 Host lava

Tentative calculations were based on olivine – liquid/glass [43] and clinopyroxene – liquid/glass [44] geothermometers. However, calculated K D are respectively 0.658 for olivine Fo 78.6, 0.902 for olivine Fo 72.8 and 0.960 for olivine Fo 71.1, that differ from the experimental equilibrium K D of 0.300. Similarly, K D are 0.715 for clinopyroxene Wo 50.4, 0.661 for Wo 48.4 and 0.850 for Wo 43.2, that differ from the experimental equilibrium K D of 0.275. Actually, the basanite sample LTZ13 corresponds to a partly cumulative lava (“ankaramite” facies), containing also olivine xenocrysts (Table 3). Considering an assumed liquid (MgO = 8–9 wt%, FeO = 14–15 wt%) in equilibrium with olivine and pyroxene, temperature of 1,300°C and pressure of 11 kbar (1.1 GPa) are estimated.

4.3.2 Xenoliths

4.3.2.1 Thermometry

Graphical estimations in quadrilateral pyroxene diagram according to [45] suggest a temperature range from 920 to 1,080°C for a pressure of 5 kbar (0.5 GPa) (Figure 5) but note that these thermometric limits are nearly the same between 1 atm and 10 kbar.

More precise equilibrium temperatures of xenolith were determined by applying (1) the empirical single pyroxene thermobarometer of [46] based on Cr–Al solubility in (ortho- or clino-) pyroxene, (2) the two-pyroxenes thermometer of [47], based on Ca-exchange between clino- and ortho- pyroxenes, (3) the partitioning of Na between ortho- and clino- pyroxenes and Ca (apfu) content of orthopyroxene alone proposed by [48], (4) olivine-spinel exchange of [49] and (5) clino-ortho-pyroxenes equilibrium of ref. [50]. For these calculations, only data on well crystallized and identified phases have been used to avoid any unknown mantle process which may occur during recrystallization process. Calculated temperatures are listed in Table 7.

Calculated temperatures using single pyroxene thermometer of [46] yield values between 840 and 900°C with orthopyroxene data, except two values at 1,260°C (for orthopyroxene analyses 19 and 20 which are Cr-richer that witness deeper equilibrium) while values obtained when using clinopyroxene data are between 1,090 and 1,220°C (Table 7, Figure 9). Empirical two pyroxene method of [47] give the temperature values of 1,070–1,130°C while the range of 750–900°C (except 1,190°C for 19 and 20) have been obtained through formulae of [48] when using Na and Ca of pyroxene porphyrocrysts. Olivine-spinel exchange method of [49] give the temperature values of 1,005–1,220°C. Two-pyroxenes geothermometer of [50] was used. We obtain 1,183.4°C for cpx Ca-poorest versus opx Ca-poorest and 1,124.5°C for cpx Ca-richest versus opx Ca-poorest. Values with Cr-orthopyroxene 19 and 20 are up to 1,135°C.

Results are scattered. Values obtained with three thermometers (two single orthopyroxene and one cpx–opx of [46] and [48] are rather low (750–900°C). They do not likely correspond to wehrlite crystallization but reflect probably late re-equilibration. Values obtained with the single clinopyroxene [46], olivine–spinel [49] and cpx–opx [50] give higher temperatures (1,005–1,220°C), reflecting more probably crystallization temperatures of mantle xenoliths (see discussions in [48,51,52]. The same value of 1,180°C is obtained with cpx Ca-poorest versus opx Ca-poorest thermometry of [50] and corresponds to the highest result with olivine-spinel thermometry. A bracket of 1,180 ± 40 = 1,140–1,220°C (maximum calculated) might match the effective temperature.

4.3.2.2 Barometry

Unfortunately, there is no direct method for determining equilibrium pressure in spinel peridotite xenoliths. Despite use of the Ca-in-olivine barometer [53] in some investigations, it has been demonstrated that it is incorrect, and its application may not provide reliable results [52,54,55].

Using formulas of [46], values from clinopyroxene mainly range from 0.58 to 0.94 GPa (and some values from 3.0 to 3.5 GPa corresponding to very deep pressures) whereas, from orthopyroxene, two groups of values are identified, one around 0.16 GPa and the second from 2.24 to 2.58 GPa (Table 7, Figure 9).

The two-pyroxenes geobarometer [50] give values between 1.4 and 2.1 GPa. In addition, assuming a temperature of 1,150°C, clinopyroxene yields pressures of 1.08–1.68 GPa (barometer of [56]). Several values, between 1.5 and 2.0 GPa, seem possible pressures of xenoliths formation. These values are close of those experimental equilibria (1.61–1.87 GPa) between spinel lherzolite and garnet lherzolite determined by [57]. Later, xenoliths have been reequilibrated from 0.9 to 0.6 GPa and possibly down to 0.16 GPa.

The corresponding depths using the conversion of 33 km/GPa are between 49.5 km (for 1.5 GPa) and 66 km (for 2.0 GPa), that is to say 33–37 km of crust plus 17–29 km of mantle.

When plotted in P-T diagram (Figure 9, adapted from [58]), calculated values form four clusters. The group with temperatures close to 1,100–1,200°C and pressures around 1.5–2.0 GPa obtained following [50] follow the same geotherm as the Youkou spinel lherzolite, in Adamawa, proposed by [58]. It corresponds to a fairly hot geotherm of 60 mW/m2, between the “continental geotherm” and the “static rift geotherm.” It is consistent with geophysical data obtained in Adamawa. Such high geotherm might result from the regional active tectonic and/or the occurrence of a rising mantle plume, as discussed by [59] for Ethiopian plateau.

5 Discussion

5.1 Mantle origin of Hosséré Do Guessa wehrlite xenoliths

Mio-Pliocene basanite lava flows and volcanic deposits in the Adamawa plateau [36,60,61] are characterized by the occurrence of a large number of ultramafic xenoliths [17,18,58]. Wehrlite xenoliths, discovered in Hosséré Do Guessa volcano, were unknown so far in the Adamawa Plateau.

These wehrlites exhibit poikilitic textures, which are sometimes ascribed to cumulate rocks crystalized from magma liquid [62,63]. However, many other features suggested by texture and mineral compositions show that Hosséré Do Guessa wehrlites are xenoliths from mantle origin. They are not consistent with the hypothesis of large volume of cumulates, since the latter are commonly associated with considerable compositional variation [64]. The poikilitic texture seems to be acquired during shallow mantle deformation which have led to strong recrystallisation of olivine [65]. As the northern part of Ngaoundéré basement have been transected in its large part by numerous Pan-African transpressive stick-slip-faults down to the mantle [13,22,28,29], reworking of these faults might have affected the shallow upper lithospheric mantle, as suggested by [42] for peridotite xenoliths of Iraya volcano in Japan.

Additionally, mineral composition of studied wehrlites strongly supports the mantle origin hypothesis of these rocks. Olivine is highly magnesian with Fo between 90.8 and 91.4 and has low CaO (<0.1 wt%, see [66]) and high NiO (0.24–0.48 wt%) contents, compatible with of mantle origin [67]. Cr# (Cr/Cr + Al) of spinel is low (12) and its composition plots in the mantle stability field of [41,68] with TiO2 and Fe2+/Fe3+ values close to mantle spinel composition. Clinopyroxene is Al-rich (5.0–5.9 wt% Al2O3) and orthopyroxene is Al-poor (0.7–1.3 wt% Al2O3, leading to inheritance from original garnet phase [69] after uplift [70].

Vertical movements under the Adamawa plateau have been suggested by geophysical studies [7]. The crust was uplifted by upward migration of the lithosphere-asthenosphere boundary from 180 to 80 km [2,3,4,5,6]. Poikilitic textures of Hosséré Do Guessa wehrlites may thus result from the solid-state tectonic relaxation as have been suggested by [34,71], consistent with the tectonic scenario. Hosséré Do Guessa wehrlites would not be comparable to cumulative wehrlites and xenoliths of magmatic origin from crystal mush, such as wehrlites described in Batoke, Mt. Cameroon volcano [31].

As the crustal thickness is estimated around 33–37 km at the north of Ngaoundéré, the studied xenoliths should have been sampled below, in the upper mantle, 50–66 km deep. The referring depths locate the wehrlite source close to the mantle-crust transition zone as that have been suggested by ref. [72]. It is thus possible that the wehrlite represents the uprising part of the high-temperature mantle peridotites, which have been metasomatized by magma fluids during upwelling (see below).

5.2 Melt-rock-fluid interactions: the wehrlite and carbonatite paradigm

Petrographic studies point out the presence of discrete orthopyroxene crystals and symplectite microtexture that are characteristic features of peridotites of mantle origin [73].

It is pointed out [74] that orthopyroxene-poor peridotites result, in general, from reactions with small volumes of carbonate/carbonatite melt, accompanying CO2 degassing, according to the reaction: enstatite + dolomite (melt) → forsterite + diopside + CO2 (vapour) (“wehrlitisation”).

Fluids-rock interaction might have affected the lithospheric mantle beneath the Adamawa plateau as have been suggested [58]. Fluids might have circulated during or after tectonic recrystallization along Pan-African stick-slip-faults at high temperatures. The nature of the circulating fluids might be carbonatitic, as proposed by ref. [58] for Youkou sub-continental mantle. Pockets of carbonate were identified in basalts, north and east of Ngaoundéré [61].

Later, re-equilibrations occurred at low depths (ca. 7 km) in the upper crust, following volcanic eruptions, with cooling from 900°C down to 750°C.

Numerous lukewarm (<22°C) springs are described north of Ngaoundéré [12]. Carbonated hot springs and geysers occur at 200–300 km north of Ngaoundéré, close to Tchabal Mbabo volcano.

6 Conclusion

Wehrlites from Hosséré Do Guessa volcano in Adamawa plateau have a mantle origin. They suffered movements of Pan-African strict-slip-faults during Adamawa upwelling at Tertiary times, after the solid state tectonic relaxation. Hosséré Do Guessa wehrlites result from reactions with carbonate/carbonatite melt, accompanying CO2 degassing and then a metasomatic event after fluids phase circulation at depth. They have crystallized at 1.5–2.0 GPa, which corresponds to a depth of 50–66 km, at a temperature of 1,140–1,220°C, and then been equilibrated until 900–750°C, between 0.9 and 0.6 (perhaps until 0.2) GPa at shallow depth.

Acknowledgments

Authors greatly thank the “Agence Universitaire de la Francophonie (AUF)” through the BAGL (Bureau Afrique Centrale et des Grands Lacs), for financial support of “Le Projet de soutien aux équipes de recherche 2012/2013_No 51110SU201” in all aspect (from field works to laboratory analyses). The contribution of “Department of Earth Sciences, UMR CNRS 8148 GEOPS” of the University Paris-Saclay, France, is greatly appreciated. B. Bonin and A. Pouclet are warmly thanked for useful remarks. Fruitful remarks by F. Casetta and an anonymous reviewer have greatly helped us to improve the manuscript.

  1. Author contributions: OFN, ZNNN, AFM and AH made field studies, JMB made electron microprobe analyses and OFN and JMB prepared the article.

  2. Conflict of interest: Authors state no conflict of interest.

References

[1] Fagny AM, Nkouandou OF, Bardintzeff JM, Guillou H, Iancu GO, Ndassa ZNN, Temdjim R. Petrology and geochemistry of the Tchabal Mbabo volcano in Cameroon volcanic line (Cameroon, Central Africa): An intra-continental alkaline volcanism. J Afr Earth Sci. 2020;170(103832):1–27.10.1016/j.jafrearsci.2020.103832Search in Google Scholar

[2] Browne SE, Fairhead JD. Gravity study of the Central African Rift System: a model of continental disruption 1. The Ngaoundéré and Abu Gabra rifts. In: Morgan P, Baker BH, editors. Processes of planetary rifting. Tectonophysics. Vol. 94. 1983. p. 187–203.10.1016/B978-0-444-42198-2.50018-3Search in Google Scholar

[3] Girod M, Dautria JM, Ball E, Soba D. Estimation de la profondeur du Moho, sous le massif volcanique de l’Adamaoua (Cameroun), à partir de l’étude d’enclaves de lherzolite. Comptes Rendus de l’Académie des Sciences Paris 298 (II, 16); 1984. p. 699–704.Search in Google Scholar

[4] Dautria JM, Girod M. Les enclaves de lherzolite à spinelle et plagioclase du volcan de Dibi (Adamaoua, Cameroun): des témoins du manteau anormal. Bull de Minéral. 1986;109:275–286.10.3406/bulmi.1986.7934Search in Google Scholar

[5] Fairhead JD, Okereke CS. Depths to major density contrast beneath the West-Africa rift system in Nigeria and Cameroon based on the spectral analysis of gravity of data. J Afr Earth Sci. 1988;7(5/6):769–77.10.1016/0899-5362(88)90018-8Search in Google Scholar

[6] Poudjom Djomani YH, Diament M, Albouy Y. Mechanical behavior of the lithosphere Beneath the Adamawa Up lift (Cameroon, West Africa) based on gravity data. J Afr Earth Sci. 1992;15:81–90.10.1016/0899-5362(92)90009-2Search in Google Scholar

[7] Poudjom Djomani YH, Diament M, Wilson M. Lithospheric structure across the Adamawa plateau (Cameroon) from gravity studies. Tectonophysics. 1997;237:317–27.10.1016/S0040-1951(96)00280-6Search in Google Scholar

[8] Tokam APK, Tabod CT, Nyblade AA, Julià J, Wiens DA, Pasyanos ME. Structure of the crust beneath Cameroon, West Africa, from the joint inversion of Rayleigh wave group velocities and receiver functions. Geophys J Int. 2010;183(2):1061–76.10.1111/j.1365-246X.2010.04776.xSearch in Google Scholar

[9] De Plaen RSM, Bastow ID, Chambers EL, Keir D, Gallacher RJ, Keane J. The development of magmatism along the Cameroon Volcanic Line: Evidence from seismicity and seismic anisotropy. J Geophys Res Solid Earth. 2014;119(5):4233–52.10.1002/2013JB010583Search in Google Scholar

[10] Eyike A, Ebbing J. Lithospheric structure of the West and Central African Rift System from regional three-dimensional gravity modelling. South Afr J Geol. 2015;118(3):285–98.10.2113/gssajg.118.3.285Search in Google Scholar

[11] Ngalamo JFG, Bisso D, Abdelsalam MG, Atekwana EA, Katumwehe AB, Ekodeck GE. Geophysical imaging of metacratonizaton in the northern edge of the Congo craton in Cameroon. J Afr Earth Sci. 2017;129(94–107):2017.10.1016/j.jafrearsci.2016.12.010Search in Google Scholar

[12] Njeudjang K, Abate Essi JM, Kana JD, Teikeu WA, Njandjock Nouck P, Djongyang N, et al. Gravity investigation of the Cameroon Volcanic Line in Adamawa region: Geothermal features and structural control. J Afr Earth Sci. 2020;165:103809.10.1016/j.jafrearsci.2020.103809Search in Google Scholar

[13] Dorbath C, Dorbath L, Fairhead JD, Stuart GW. A teleseismic delay time study across the central African Shear Zone in the Adamawa region of Cameroon. West Afr Geophys J R Astron Soc. 1986;86:751–66.10.1111/j.1365-246X.1986.tb00658.xSearch in Google Scholar

[14] Menzies MA, Halliday AN, Palacz Z, Hunter RH, Upton BGJ, Aspen P, et al. Evidence from mantle xenoliths for an enriched lithospheric keel under the Outer Hebrides. Nature. 1987;325:44–7.10.1038/325044a0Search in Google Scholar

[15] Lee DC, Halliday AN, Davies GR, Essene EJ, Fitton JG, Temdjim R. Melt enrichment of shallow depleted mantle: a detailed petrological, trace element and isotopic study of mantle-derived xenoliths and megacrysts from the Cameroon Line. J Petrol. 1996;37:415–41.10.1093/petrology/37.2.415Search in Google Scholar

[16] Temdjim R. Contribution à la connaissance du manteau supérieur du Cameroun au travers de l’étude des enclaves ultrabasiques et basiques remontées par les volcans de Youkou (Adamaoua) et de Nyos (Ligne du Cameroun). Thèse Doctorat d’Etat. Cameroun: Université Yaoundé1; 2005. p. 423Search in Google Scholar

[17] Nkouandou OF, Temdjim R. Petrology of spinel lherzolite xenoliths and host basaltic lava from Ngao Voglar volcano, Adamawa Massif (Cameroon Volcanic Line, West Africa): equilibrium conditions and mantle characteristics. J Geosci. 2011;56:375–87.10.3190/jgeosci.108Search in Google Scholar

[18] Nkouandou OF, Bardintzeff JM, Fagny AM. Sub-continental lithospheric mantle structure beneath the Adamawa plateau inferred from the petrology of ultramafic xenoliths from Ngaoundéré (Adamawa plateau, Cameroon, Central Africa). J Afr Earth Sci. 2015;111:26–40.10.1016/j.jafrearsci.2015.07.004Search in Google Scholar

[19] Nnange JM, Ngako V, Fairhead JD, Ebinger CJ. Depths to density discontinuities beneath the Adamawa Plateau region, Central Africa, from spectral analyses of new and existing gravity data. J Afr Earth Sci. 2000;30(4):887–901.10.1016/S0899-5362(00)00058-0Search in Google Scholar

[20] Tchameni R, Pouclet A, Penaye J, Ganwa AA, Toteu SF. Petrography and geochemistry of the Ngaoundéré Pan-African granitoids in central North Cameroon: implications for their sources and geological setting. J Afr Earth Sci. 2006;44:511–29.10.1016/j.jafrearsci.2005.11.017Search in Google Scholar

[21] Ganwa AA, Frisch W, Siebel W, Ekodeck GE, Cosmas SK, Ngako V. Archean inheritances in the pyroxene-amphibole bearing gneiss of the Méiganga area (Central North Cameroon): Geochemical and 207Pb/206Pb age imprints. Comptes Rendus Géosc. 2008;340:211–22.10.1016/j.crte.2007.12.009Search in Google Scholar

[22] Moreau C, Regnoult JM, Déruelle B, Bobineau B. A new tectonic model for Cameroon line, central Africa. Tectonophysics. 1987;139:317–34.10.1016/0040-1951(87)90206-XSearch in Google Scholar

[23] Wilson M, Guiraud R. Magmatism and rifting in Western and Central Africa, from Late Jurassic to Recent times. Tectonophysics. 1992;213:203–25.10.1016/B978-0-444-89912-5.50038-7Search in Google Scholar

[24] Cornacchia M, Dars R. Un trait structural majeur du continent africain. Les linéaments centre africain du Cameroun au golfe d’Aden. Bull de la Soc Géolo de Fr. 1983;25:101–9.10.2113/gssgfbull.S7-XXV.1.101Search in Google Scholar

[25] Guiraud R, Bosworth W, Thierry J, Delplanque A. Phanerozoic geological evolution of Northern and Central Africa: An overview. J Afr Earth Sci. 2005;43(1–3):83–143.10.1016/j.jafrearsci.2005.07.017Search in Google Scholar

[26] Mbowou IBG, Nguihdama D, Yamgouot FN, Ntoumbe M, Youpoungam AA, Ngounouno I. Mineral chemistry of wehrlite xenoliths hosted in basalts from the SW of Hosséré Dammougalré (Adamawa Plateau, Cameroon): Thermobarometric implications. Open J Geol. 2017;7:1465–77.10.4236/ojg.2017.710098Search in Google Scholar

[27] Pouchou JL, Pichoir F. Quantitative analysis of homogeneous or stratified microvolumes applying the model «PAP». In Electron Probe quantification. In: Heinriche DE. editor. Newbury, New York, US: Plenum Press; 1991. p. 31–75.10.1007/978-1-4899-2617-3_4Search in Google Scholar

[28] Ngangom E. Étude tectonique du fossé Crétacé de la Mbéré et du Djérem, Sud Adamawa, Cameroun. Bull Cent de Rech Expl-Prod Elf-Aquitaine. 1983;7:339–47.Search in Google Scholar

[29] Dumont JF. Étude structurale des bordures nord et sud du plateau de l’Adamaoua: influence du contexte atlantique. Géodynamique. 1987;2(1):56–68.Search in Google Scholar

[30] Le Maitre RW, editor. Igneous rocks, a classification and glossary of terms. (Recommendations of the IUGS subcommission on the systematics of igneous rocks). Cambridge: Cambridge University Press; 2002. p. 252.10.1017/CBO9780511535581Search in Google Scholar

[31] Wandji P, Tsafack JPF, Bardintzeff JM, Nkouathio DG, Kagou Dongmo A, Bellon H, et al. Xenoliths of dunites, wehrlites and clinopyroxenites in the basanites from Batoke volcanic cone (Mount Cameroon, Central Africa): petrogenetic implications. Mineral Petrol. 2009;96(1):81–98.10.1007/s00710-008-0040-3Search in Google Scholar

[32] Shaw CSJ, Eyzaguirre J, Fryer B, Gagnon J. Regional variations in the mineralogy of metasomatic assemblages in mantle xenoliths from the West Eifel volcanic field, Germany. J Petrol. 2005;46(5):945–72.10.1093/petrology/egi006Search in Google Scholar

[33] Villaseca C, Ancochea E, Orejana D, Jeffries TE. Composition and evolution of the lithospheric mantle in central Spain: inferences from peridotite xenoliths from the Cenozoic Calatrava volcanic field. In: Coltorti M, Downes H, Grégoire M, O’Reilly SY, editors. Petrological evolution of the European lithospheric mantle. Geological Society. 337, London: Special Publications; 2010. p. 125–51.10.1144/SP337.7Search in Google Scholar

[34] Mercier JCC, Nicolas A. Textures and fabrics of upper-mantle peridotites as illustrated by xenoliths from basalts. J Petrol. 1975;16(2):454–87.10.1093/petrology/16.1.454Search in Google Scholar

[35] Njankouo Ndassa ZN. 2019. Pétrologie et géochimie des péridotites en enclaves dans les basaltes de Ngaoundéré et ses environs: nature du manteau subcontinental sous le plateau de l’Adamaoua (Plateau de l’Adamaoua, Cameroun, Afrique centrale). Thèse Université de Ngaoundéré, 232 pp + annexes.Search in Google Scholar

[36] Njankouo Ndassa ZN, Nkouandou OF, Bardintzeff JM, Ganwa AA, Fagny MA, Tizi A. Petrology of peridotite host basaltic lavas of northern Ngaoundéré (Adamawa plateau, Cameroon, Central Africa). Int J Adv Geosci. 2019;7(2):85–94.10.14419/ijag.v7i2.28941Search in Google Scholar

[37] Wandji P, Bardintzeff JM, Ménard JJ, Tchoua FM. The alkaline fassaite-bearing volcanic province of the Noun Plain (West-Cameroon). Neues Jahrbuch für Mineralogie. Monatshefte. 2000;1:1–14.Search in Google Scholar

[38] Embey-Isztin A. The role of melt depletion versus refertilization in the major element chemistry of four-phase spinel peridotite xenoliths. Central European. Geology. 2016;59(1–4):60–86.10.1556/24.59.2016.002Search in Google Scholar

[39] Rudnick RL, McDonough WF, Chappell BW. Carbonatite metasomatism in the northern Tanzanian mantle: petrographic and geochemical characteristics. Earth Planet Sci Lett. 1993;114:463–75.10.1016/0012-821X(93)90076-LSearch in Google Scholar

[40] Morimoto N, Fabries J, Ferguson AK, Ginzburg IV, Ross M, Seifert FA, et al. Nomenclature of pyroxenes. Mineral Mag. 1988;52:535–50.10.1180/minmag.1988.052.367.15Search in Google Scholar

[41] Carswell DA. Mantle derived lherzolite nodules associated with kimberlite, carbonatite and basalt magmatism: A review. Lithos. 1980;13(2):121–38.10.1016/0024-4937(80)90013-4Search in Google Scholar

[42] Arai S. Characterization of spinel peridotites by olivine-spinel compositional relationships: review and interpretation. Chem Geol. 1994;113(3–4):191–204.10.1016/0009-2541(94)90066-3Search in Google Scholar

[43] Putirka KD, Perfit M, Ryerson FJ, Jackson MG. Ambient and excess mantle temperatures, olivine thermometry, and active vs. passive upwelling. Chem Geol. 2007;241(3–4):177–206.10.1016/j.chemgeo.2007.01.014Search in Google Scholar

[44] Putirka KD, Mikaelian H, Ryerson FJ, Shaw H. New clinopyroxene-liquid thermobarometers for mafic, evolved, and volatile-bearing lava compositions, with applications to lavas from Tibet and the Snake River Plain, Idaho. Am Mineral. 2003;88(10):1542–54.10.2138/am-2003-1017Search in Google Scholar

[45] Lindsley DH. Pyroxene thermometry. Am Mineral. 1983;68(5–6):477–93.Search in Google Scholar

[46] Mercier JCC. Single-pyroxene thermobarometry. Tectonophysics. 1980;70:1–37.10.1016/0040-1951(80)90019-0Search in Google Scholar

[47] Wells PRA. Pyroxene thermometry in simple and complex systems. Contrib Mineral Petrol. 1977;62:129–39.10.1007/BF00372872Search in Google Scholar

[48] Brey GP, Köhler T. Geothermobarometry in four phase lherzolites II. New thermobarometers, and practical assessment of existing thermometers. J Petrol. 1990;31:1353–78.10.1093/petrology/31.6.1353Search in Google Scholar

[49] O’Neill HStC, Wall VJ. The olivine–orthopyroxene–spinel oxygen geobarometer, the nickel precipitation curve, and the oxygen fugacity of the Earth’s upper mantle. J Petrol. 1987;28:1169–91.10.1093/petrology/28.6.1169Search in Google Scholar

[50] Putirka KD. Thermometers and barometers for volcanic systems. Rev Mineral Geochem. 2008;69(1):61–120.10.1515/9781501508486-004Search in Google Scholar

[51] Glaser SM, Foley SF, Günther D. Trace element compositions of minerals in garnet and spinel peridotite xenoliths from the Vitim volcanic field, Transbaikalia, eastern Siberia. Lithos. 1999;48(1–4):263–85.10.1016/S0024-4937(99)00032-8Search in Google Scholar

[52] Medaris Jr,GL, Wang HF, Fournelle JH, Zimmer JH, Jelínek E. A cautionary tale of spinel peridotite thermobarometry: an example from xenoliths of Kozákov volcano. Czech Repub Geolines. 1999;9:92–6.Search in Google Scholar

[53] Köhler TP, Brey GP. Calcium exchange between olivine and clinopyroxene calibrated as a geothermobarometer for natural peridotites from 2 to 60 kb with applications. Geochim Cosmochim Acta. 1990;54:2375–88.10.1016/0016-7037(90)90226-BSearch in Google Scholar

[54] O’Reilly SY, Chen D, Griffin WL, Ryan CG. Minor elements in olivine from spinel lherzolite xenoliths: implications for thermobarometry. Mineral Mag. 1997;61:257–69.10.1180/minmag.1997.061.405.09Search in Google Scholar

[55] Christensen NI, Medaris JrLG, Wang HF, Jelinek E. Depth variation of seismic anisotropy and petrology in central European lithosphere: a tectonothermal synthesis from spinel lherzolites. J Geophys Res. 2001;160(B1):645–64.10.1029/2000JB900333Search in Google Scholar

[56] Nimis P. Clinopyroxenes from plagioclase peridotites (Zabargad Island, Red Sea) and comparison between high- and low-pressure mantle clinopyroxenes. Mineral Petrol. 1995;53(1–3):49–61.10.1007/BF01171946Search in Google Scholar

[57] O’Neill HStC. The transition between spinel lherzolite and garnet lherzolite, and its use as a geobarometer. Contrib Mineral Petrol. 1981;77(2):185–94.10.1007/BF00636522Search in Google Scholar

[58] Njombie MPW, Temdjim R, Foley SF. Petrology of spinel lherzolite xenoliths from Youkou volcano, Adamawa Massif, Cameroon Volcanic Line: mineralogical and geochemical fingerprints of sub-rift mantle processes. Contrib Mineral Petrol. 2018;173:173–193.10.1007/s00410-018-1438-5Search in Google Scholar

[59] Meshesha D, Shinjo R, Orihashi Y. Geochemical and Sr-Nd-Pb isotopic compositions of lithospheric mantle: Spinel lherzolites in alkaline basalts from the northwestern Ethiopian plateau. J Mineral Petrol Sci. 2014;109(6):241–57.10.2465/jmps.140529Search in Google Scholar

[60] Nkouandou OF, Ngounouno I, Déruelle B, Ohnenstetter D, Montigny R, Demaiffe D. Petrology of the Mio-Pliocene Volcanism to the North and East of Ngaoundéré (Adamawa-Cameroon). Comptes Rendus Géosci. 2008;340:27–38.10.1016/j.crte.2007.10.012Search in Google Scholar

[61] Nkouandou OF, Ngounouno I, Déruelle B. Géochimie des laves basaltiques récentes des zones Nord et Est de Ngaoundéré (Plateau de l’Adamaoua, Cameroun, Afrique Centrale): pétrogenèse et nature de la source. Int J Biol Chem Sci. 2010;4(4):984–1003.10.4314/ijbcs.v4i4.63038Search in Google Scholar

[62] Lippard SJ, Shelton AW, Gass LG. ophiolite North Oman Mem Geol Soc Lond. 1986;11:178.Search in Google Scholar

[63] Girardeau J, Francheteau J. Plagioclase-wehrlites and peridotites on the East Pacific Rise (Hess Deep) and the Mid-Atlantic Ridge (DSDP Site 334): Evidence for magma percolation in the oceanic upper mantle. Earth Planet Sci Lett. 1993;115:137–49.10.1016/0012-821X(93)90218-XSearch in Google Scholar

[64] Xu YG, Menzies MA, Bodinier J-L, Bedini RM, Vroon P, Mercier JCC. Melt percolation and reaction atop a plume: evidence from the poikiloblastic peridotite xenoliths from Borée (Massif Central, France). Contrib Mineral Petrol. 1998;132(1):65–84.10.1007/s004100050405Search in Google Scholar

[65] Kaczmarek MA, Bodinier JL, Bosch D, Tommasi A, Dautria JM, Kechid SA. Metasomatized Mantle Xenoliths as a Record of the Lithospheric Mantle Evolution of the Northern Edge of the Ahaggar Swell, In Teria (Algeria). J Petrol. 2016;57(2):345–82.10.1093/petrology/egw009Search in Google Scholar

[66] Simkin T, Smith JV. Minor-element distribution in olivine. J Geol. 1970;78(3):304–25.10.1086/627519Search in Google Scholar

[67] Roeder PL, Emslie RF. Olivine-liquid equilibrium. Contrib Mineral Petrol. 1970;29:275–89.10.1007/BF00371276Search in Google Scholar

[68] Lenaz D, Kamenetsky VS, Crawford AJ, Princivalle F. Melt inclusions in detrital spinels from the SE Alps (Italy–Slovenia): a new approach to provenance studies of sedimentary basins. Contrib Mineral Petrol. 2000;139:748–58.10.1007/s004100000170Search in Google Scholar

[69] Dawson JB, Smith JV. Upper-mantle amphiboles: a review. Mineral Mag. 1982;45:35–46.10.1180/minmag.1982.045.337.04Search in Google Scholar

[70] Wallace ME, Green DH. The Effect of Bulk Rock Composition on the Stability of Amphibole in the upper Mantle: Implications for solidus positions and mantle metasomatism. Mineral Petrol. 1991;44:1–19.10.1007/BF01167097Search in Google Scholar

[71] Mercier JCC. Natural peridotites: chemical and rheological heterogeneity of the upper mantle. USA: PhD, University of New York Stony Brook; 1976.Search in Google Scholar

[72] Benn K, Nicolas A, Reuber I. Mantle-crust transition zone and origin of wehrlitic magmas: Evidence from the Oman ophiolite. Tectonophysics. 1988;151:75–85.10.1016/0040-1951(88)90241-7Search in Google Scholar

[73] Chen CH, Presnall DC, Stern RJ. Petrogenesis of Ultramafic Xenoliths from the 1800 Kaupulehu Flow, Hualalai Volcano, Hawaii. J Petrol. 1992;33:163–202.10.1093/petrology/33.1.163Search in Google Scholar

[74] Aulbach S, Lin A-B, Weiss Y, Yaxley GM. Wehrlites from continental mantle monitor the passage and degassing of carbonated melts. Geochem Perspect Lett. 2020;15:30–4.10.7185/geochemlet.2031Search in Google Scholar

[75] Temdjim R. Ultramafic xenoliths from Lake Nyos area, Cameroon volcanic line, West-central Africa: Petrography, mineral chemistry, equilibration conditions and metasomatic features. Geochemistry - Chemie der. Erde. 2012;72(1):39–60.10.1016/j.chemer.2011.07.002Search in Google Scholar

[76] Caldeira R, Munhá JM. Petrology of ultramafic nodules from São Tomé Island, Cameroon Volcanic Line (oceanic sector). J Afr Earth Sci. 2002;34(3–4):231–46.10.1016/S0899-5362(02)00022-2Search in Google Scholar

[77] Rocco I, Lustrino M, Zanetti A, Morra V, Melluso L. Petrology of ultramafic xenoliths in Cenozoic alkaline rocks of northern Madagascar (Nosy Be Archipelago). J South Am Earth Sci. 2013;41:122–39.10.1016/j.jsames.2012.06.012Search in Google Scholar

[78] Falloon TJ, Green DH, O’Neill HS, Hibberson WO. Experimental tests of low degree peridotite partial melt compositions: implications for the nature of anhydrous near-solidus peridotite melts at 1 GPa. Earth Planet Sci Lett. 1997;152(1–4):149–62.10.1016/S0012-821X(97)00155-6Search in Google Scholar
Received: 2022-01-27
Revised: 2022-08-24
Accepted: 2022-09-15
Published Online: 2022-10-17

© 2022 Oumarou Faarouk Nkouandou et al., published by De Gruyter

This work is licensed under the Creative Commons Attribution 4.0 International License.

Articles in the same Issue

  1. Regular Articles
  2. Study on observation system of seismic forward prospecting in tunnel: A case on tailrace tunnel of Wudongde hydropower station
  3. The behaviour of stress variation in sandy soil
  4. Research on the current situation of rural tourism in southern Fujian in China after the COVID-19 epidemic
  5. Late Triassic–Early Jurassic paleogeomorphic characteristics and hydrocarbon potential of the Ordos Basin, China, a case of study of the Jiyuan area
  6. Application of X-ray fluorescence mapping in turbiditic sandstones, Huai Bo Khong Formation of Nam Pat Group, Thailand
  7. Fractal expression of soil particle-size distribution at the basin scale
  8. Study on the changes in vegetation structural coverage and its response mechanism to hydrology
  9. Spatial distribution analysis of seismic activity based on GMI, LMI, and LISA in China
  10. Rock mass structural surface trace extraction based on transfer learning
  11. Hydrochemical characteristics and D–O–Sr isotopes of groundwater and surface water in the northern Longzi county of southern Tibet (southwestern China)
  12. Insights into origins of the natural gas in the Lower Paleozoic of Ordos basin, China
  13. Research on comprehensive benefits and reasonable selection of marine resources development types
  14. Embedded deformation of the rubble-mound foundation of gravity-type quay walls and influence factors
  15. Activation of Ad Damm shear zone, western Saudi Arabian margin, and its relation to the Red Sea rift system
  16. A mathematical conjecture associates Martian TARs with sand ripples
  17. Study on spatio-temporal characteristics of earthquakes in southwest China based on z-value
  18. Sedimentary facies characterization of forced regression in the Pearl River Mouth basin
  19. High-precision remote sensing mapping of aeolian sand landforms based on deep learning algorithms
  20. Experimental study on reservoir characteristics and oil-bearing properties of Chang 7 lacustrine oil shale in Yan’an area, China
  21. Estimating the volume of the 1978 Rissa quick clay landslide in Central Norway using historical aerial imagery
  22. Spatial accessibility between commercial and ecological spaces: A case study in Beijing, China
  23. Curve number estimation using rainfall and runoff data from five catchments in Sudan
  24. Urban green service equity in Xiamen based on network analysis and concentration degree of resources
  25. Spatio-temporal analysis of East Asian seismic zones based on multifractal theory
  26. Delineation of structural lineaments of Southeast Nigeria using high resolution aeromagnetic data
  27. 3D marine controlled-source electromagnetic modeling using an edge-based finite element method with a block Krylov iterative solver
  28. A comprehensive evaluation method for topographic correction model of remote sensing image based on entropy weight method
  29. Quantitative discrimination of the influences of climate change and human activity on rocky desertification based on a novel feature space model
  30. Assessment of climatic conditions for tourism in Xinjiang, China
  31. Attractiveness index of national marine parks: A study on national marine parks in coastal areas of East China Sea
  32. Effect of brackish water irrigation on the movement of water and salt in salinized soil
  33. Mapping paddy rice and rice phenology with Sentinel-1 SAR time series using a unified dynamic programming framework
  34. Analyzing the characteristics of land use distribution in typical village transects at Chinese Loess Plateau based on topographical factors
  35. Management status and policy direction of submerged marine debris for improvement of port environment in Korea
  36. Influence of Three Gorges Dam on earthquakes based on GRACE gravity field
  37. Comparative study of estimating the Curie point depth and heat flow using potential magnetic data
  38. The spatial prediction and optimization of production-living-ecological space based on Markov–PLUS model: A case study of Yunnan Province
  39. Major, trace and platinum-group element geochemistry of harzburgites and chromitites from Fuchuan, China, and its geological significance
  40. Vertical distribution of STN and STP in watershed of loess hilly region
  41. Hyperspectral denoising based on the principal component low-rank tensor decomposition
  42. Evaluation of fractures using conventional and FMI logs, and 3D seismic interpretation in continental tight sandstone reservoir
  43. U–Pb zircon dating of the Paleoproterozoic khondalite series in the northeastern Helanshan region and its geological significance
  44. Quantitatively determine the dominant driving factors of the spatial-temporal changes of vegetation-impacts of global change and human activity
  45. Can cultural tourism resources become a development feature helping rural areas to revitalize the local economy under the epidemic? An exploration of the perspective of attractiveness, satisfaction, and willingness by the revisit of Hakka cultural tourism
  46. A 3D empirical model of standard compaction curve for Thailand shales: Porosity in function of burial depth and geological time
  47. Attribution identification of terrestrial ecosystem evolution in the Yellow River Basin
  48. An intelligent approach for reservoir quality evaluation in tight sandstone reservoir using gradient boosting decision tree algorithm
  49. Detection of sub-surface fractures based on filtering, modeling, and interpreting aeromagnetic data in the Deng Deng – Garga Sarali area, Eastern Cameroon
  50. Influence of heterogeneity on fluid property variations in carbonate reservoirs with multistage hydrocarbon accumulation: A case study of the Khasib formation, Cretaceous, AB oilfield, southern Iraq
  51. Designing teaching materials with disaster maps and evaluating its effectiveness for primary students
  52. Assessment of the bender element sensors to measure seismic wave velocity of soils in the physical model
  53. Appropriated protection time and region for Qinghai–Tibet Plateau grassland
  54. Identification of high-temperature targets in remote sensing based on correspondence analysis
  55. Influence of differential diagenesis on pore evolution of the sandy conglomerate reservoir in different structural units: A case study of the Upper Permian Wutonggou Formation in eastern Junggar Basin, NW China
  56. Planting in ecologically solidified soil and its use
  57. National and regional-scale landslide indicators and indexes: Applications in Italy
  58. Occurrence of yttrium in the Zhijin phosphorus deposit in Guizhou Province, China
  59. The response of Chudao’s beach to typhoon “Lekima” (No. 1909)
  60. Soil wind erosion resistance analysis for soft rock and sand compound soil: A case study for the Mu Us Sandy Land, China
  61. Investigation into the pore structures and CH4 adsorption capacities of clay minerals in coal reservoirs in the Yangquan Mining District, North China
  62. Overview of eco-environmental impact of Xiaolangdi Water Conservancy Hub on the Yellow River
  63. Response of extreme precipitation to climatic warming in the Weihe river basin, China and its mechanism
  64. Analysis of land use change on urban landscape patterns in Northwest China: A case study of Xi’an city
  65. Optimization of interpolation parameters based on statistical experiment
  66. Late Cretaceous adakitic intrusive rocks in the Laimailang area, Gangdese batholith: Implications for the Neo-Tethyan Ocean subduction
  67. Tectonic evolution of the Eocene–Oligocene Lushi Basin in the eastern Qinling belt, Central China: Insights from paleomagnetic constraints
  68. Geographic and cartographic inconsistency factors among different cropland classification datasets: A field validation case in Cambodia
  69. Distribution of large- and medium-scale loess landslides induced by the Haiyuan Earthquake in 1920 based on field investigation and interpretation of satellite images
  70. Numerical simulation of impact and entrainment behaviors of debris flow by using SPH–DEM–FEM coupling method
  71. Study on the evaluation method and application of logging irreducible water saturation in tight sandstone reservoirs
  72. Geochemical characteristics and genesis of natural gas in the Upper Triassic Xujiahe Formation in the Sichuan Basin
  73. Wehrlite xenoliths and petrogenetic implications, Hosséré Do Guessa volcano, Adamawa plateau, Cameroon
  74. Changes in landscape pattern and ecological service value as land use evolves in the Manas River Basin
  75. Spatial structure-preserving and conflict-avoiding methods for point settlement selection
  76. Fission characteristics of heavy metal intrusion into rocks based on hydrolysis
  77. Sequence stratigraphic filling model of the Cretaceous in the western Tabei Uplift, Tarim Basin, NW China
  78. Fractal analysis of structural characteristics and prospecting of the Luanchuan polymetallic mining district, China
  79. Spatial and temporal variations of vegetation coverage and their driving factors following gully control and land consolidation in Loess Plateau, China
  80. Assessing the tourist potential of cultural–historical spatial units of Serbia using comparative application of AHP and mathematical method
  81. Urban black and odorous water body mapping from Gaofen-2 images
  82. Geochronology and geochemistry of Early Cretaceous granitic plutons in northern Great Xing’an Range, NE China, and implications for geodynamic setting
  83. Spatial planning concept for flood prevention in the Kedurus River watershed
  84. Geophysical exploration and geological appraisal of the Siah Diq porphyry Cu–Au prospect: A recent discovery in the Chagai volcano magmatic arc, SW Pakistan
  85. Possibility of using the DInSAR method in the development of vertical crustal movements with Sentinel-1 data
  86. Using modified inverse distance weight and principal component analysis for spatial interpolation of foundation settlement based on geodetic observations
  87. Geochemical properties and heavy metal contents of carbonaceous rocks in the Pliocene siliciclastic rock sequence from southeastern Denizli-Turkey
  88. Study on water regime assessment and prediction of stream flow based on an improved RVA
  89. A new method to explore the abnormal space of urban hidden dangers under epidemic outbreak and its prevention and control: A case study of Jinan City
  90. Milankovitch cycles and the astronomical time scale of the Zhujiang Formation in the Baiyun Sag, Pearl River Mouth Basin, China
  91. Shear strength and meso-pore characteristic of saturated compacted loess
  92. Key point extraction method for spatial objects in high-resolution remote sensing images based on multi-hot cross-entropy loss
  93. Identifying driving factors of the runoff coefficient based on the geographic detector model in the upper reaches of Huaihe River Basin
  94. Study on rainfall early warning model for Xiangmi Lake slope based on unsaturated soil mechanics
  95. Extraction of mineralized indicator minerals using ensemble learning model optimized by SSA based on hyperspectral image
  96. Lithofacies discrimination using seismic anisotropic attributes from logging data in Muglad Basin, South Sudan
  97. Three-dimensional modeling of loose layers based on stratum development law
  98. Occurrence, sources, and potential risk of polycyclic aromatic hydrocarbons in southern Xinjiang, China
  99. Attribution analysis of different driving forces on vegetation and streamflow variation in the Jialing River Basin, China
  100. Slope characteristics of urban construction land and its correlation with ground slope in China
  101. Limitations of the Yang’s breaking wave force formula and its improvement under a wider range of breaker conditions
  102. The spatial-temporal pattern evolution and influencing factors of county-scale tourism efficiency in Xinjiang, China
  103. Evaluation and analysis of observed soil temperature data over Northwest China
  104. Agriculture and aquaculture land-use change prediction in five central coastal provinces of Vietnam using ANN, SVR, and SARIMA models
  105. Leaf color attributes of urban colored-leaf plants
  106. Application of statistical and machine learning techniques for landslide susceptibility mapping in the Himalayan road corridors
  107. Sediment provenance in the Northern South China Sea since the Late Miocene
  108. Drones applications for smart cities: Monitoring palm trees and street lights
  109. Double rupture event in the Tianshan Mountains: A case study of the 2021 Mw 5.3 Baicheng earthquake, NW China
  110. Review Article
  111. Mobile phone indoor scene features recognition localization method based on semantic constraint of building map location anchor
  112. Technical Note
  113. Experimental analysis on creep mechanics of unsaturated soil based on empirical model
  114. Rapid Communications
  115. A protocol for canopy cover monitoring on forest restoration projects using low-cost drones
  116. Landscape tree species recognition using RedEdge-MX: Suitability analysis of two different texture extraction forms under MLC and RF supervision
  117. Special Issue: Geoethics 2022 - Part I
  118. Geomorphological and hydrological heritage of Mt. Stara Planina in SE Serbia: From river protection initiative to potential geotouristic destination
  119. Geotourism and geoethics as support for rural development in the Knjaževac municipality, Serbia
  120. Modeling spa destination choice for leveraging hydrogeothermal potentials in Serbia
https://doi.org/10.1515/geo-2022-0408
Keywords for this article
wehrlite; metasomatism; Hosséré Do Guessa; Adamawa plateau; Cameroon
Creative Commons
BY 4.0

Articles in the same Issue

  1. Regular Articles
  2. Study on observation system of seismic forward prospecting in tunnel: A case on tailrace tunnel of Wudongde hydropower station
  3. The behaviour of stress variation in sandy soil
  4. Research on the current situation of rural tourism in southern Fujian in China after the COVID-19 epidemic
  5. Late Triassic–Early Jurassic paleogeomorphic characteristics and hydrocarbon potential of the Ordos Basin, China, a case of study of the Jiyuan area
  6. Application of X-ray fluorescence mapping in turbiditic sandstones, Huai Bo Khong Formation of Nam Pat Group, Thailand
  7. Fractal expression of soil particle-size distribution at the basin scale
  8. Study on the changes in vegetation structural coverage and its response mechanism to hydrology
  9. Spatial distribution analysis of seismic activity based on GMI, LMI, and LISA in China
  10. Rock mass structural surface trace extraction based on transfer learning
  11. Hydrochemical characteristics and D–O–Sr isotopes of groundwater and surface water in the northern Longzi county of southern Tibet (southwestern China)
  12. Insights into origins of the natural gas in the Lower Paleozoic of Ordos basin, China
  13. Research on comprehensive benefits and reasonable selection of marine resources development types
  14. Embedded deformation of the rubble-mound foundation of gravity-type quay walls and influence factors
  15. Activation of Ad Damm shear zone, western Saudi Arabian margin, and its relation to the Red Sea rift system
  16. A mathematical conjecture associates Martian TARs with sand ripples
  17. Study on spatio-temporal characteristics of earthquakes in southwest China based on z-value
  18. Sedimentary facies characterization of forced regression in the Pearl River Mouth basin
  19. High-precision remote sensing mapping of aeolian sand landforms based on deep learning algorithms
  20. Experimental study on reservoir characteristics and oil-bearing properties of Chang 7 lacustrine oil shale in Yan’an area, China
  21. Estimating the volume of the 1978 Rissa quick clay landslide in Central Norway using historical aerial imagery
  22. Spatial accessibility between commercial and ecological spaces: A case study in Beijing, China
  23. Curve number estimation using rainfall and runoff data from five catchments in Sudan
  24. Urban green service equity in Xiamen based on network analysis and concentration degree of resources
  25. Spatio-temporal analysis of East Asian seismic zones based on multifractal theory
  26. Delineation of structural lineaments of Southeast Nigeria using high resolution aeromagnetic data
  27. 3D marine controlled-source electromagnetic modeling using an edge-based finite element method with a block Krylov iterative solver
  28. A comprehensive evaluation method for topographic correction model of remote sensing image based on entropy weight method
  29. Quantitative discrimination of the influences of climate change and human activity on rocky desertification based on a novel feature space model
  30. Assessment of climatic conditions for tourism in Xinjiang, China
  31. Attractiveness index of national marine parks: A study on national marine parks in coastal areas of East China Sea
  32. Effect of brackish water irrigation on the movement of water and salt in salinized soil
  33. Mapping paddy rice and rice phenology with Sentinel-1 SAR time series using a unified dynamic programming framework
  34. Analyzing the characteristics of land use distribution in typical village transects at Chinese Loess Plateau based on topographical factors
  35. Management status and policy direction of submerged marine debris for improvement of port environment in Korea
  36. Influence of Three Gorges Dam on earthquakes based on GRACE gravity field
  37. Comparative study of estimating the Curie point depth and heat flow using potential magnetic data
  38. The spatial prediction and optimization of production-living-ecological space based on Markov–PLUS model: A case study of Yunnan Province
  39. Major, trace and platinum-group element geochemistry of harzburgites and chromitites from Fuchuan, China, and its geological significance
  40. Vertical distribution of STN and STP in watershed of loess hilly region
  41. Hyperspectral denoising based on the principal component low-rank tensor decomposition
  42. Evaluation of fractures using conventional and FMI logs, and 3D seismic interpretation in continental tight sandstone reservoir
  43. U–Pb zircon dating of the Paleoproterozoic khondalite series in the northeastern Helanshan region and its geological significance
  44. Quantitatively determine the dominant driving factors of the spatial-temporal changes of vegetation-impacts of global change and human activity
  45. Can cultural tourism resources become a development feature helping rural areas to revitalize the local economy under the epidemic? An exploration of the perspective of attractiveness, satisfaction, and willingness by the revisit of Hakka cultural tourism
  46. A 3D empirical model of standard compaction curve for Thailand shales: Porosity in function of burial depth and geological time
  47. Attribution identification of terrestrial ecosystem evolution in the Yellow River Basin
  48. An intelligent approach for reservoir quality evaluation in tight sandstone reservoir using gradient boosting decision tree algorithm
  49. Detection of sub-surface fractures based on filtering, modeling, and interpreting aeromagnetic data in the Deng Deng – Garga Sarali area, Eastern Cameroon
  50. Influence of heterogeneity on fluid property variations in carbonate reservoirs with multistage hydrocarbon accumulation: A case study of the Khasib formation, Cretaceous, AB oilfield, southern Iraq
  51. Designing teaching materials with disaster maps and evaluating its effectiveness for primary students
  52. Assessment of the bender element sensors to measure seismic wave velocity of soils in the physical model
  53. Appropriated protection time and region for Qinghai–Tibet Plateau grassland
  54. Identification of high-temperature targets in remote sensing based on correspondence analysis
  55. Influence of differential diagenesis on pore evolution of the sandy conglomerate reservoir in different structural units: A case study of the Upper Permian Wutonggou Formation in eastern Junggar Basin, NW China
  56. Planting in ecologically solidified soil and its use
  57. National and regional-scale landslide indicators and indexes: Applications in Italy
  58. Occurrence of yttrium in the Zhijin phosphorus deposit in Guizhou Province, China
  59. The response of Chudao’s beach to typhoon “Lekima” (No. 1909)
  60. Soil wind erosion resistance analysis for soft rock and sand compound soil: A case study for the Mu Us Sandy Land, China
  61. Investigation into the pore structures and CH4 adsorption capacities of clay minerals in coal reservoirs in the Yangquan Mining District, North China
  62. Overview of eco-environmental impact of Xiaolangdi Water Conservancy Hub on the Yellow River
  63. Response of extreme precipitation to climatic warming in the Weihe river basin, China and its mechanism
  64. Analysis of land use change on urban landscape patterns in Northwest China: A case study of Xi’an city
  65. Optimization of interpolation parameters based on statistical experiment
  66. Late Cretaceous adakitic intrusive rocks in the Laimailang area, Gangdese batholith: Implications for the Neo-Tethyan Ocean subduction
  67. Tectonic evolution of the Eocene–Oligocene Lushi Basin in the eastern Qinling belt, Central China: Insights from paleomagnetic constraints
  68. Geographic and cartographic inconsistency factors among different cropland classification datasets: A field validation case in Cambodia
  69. Distribution of large- and medium-scale loess landslides induced by the Haiyuan Earthquake in 1920 based on field investigation and interpretation of satellite images
  70. Numerical simulation of impact and entrainment behaviors of debris flow by using SPH–DEM–FEM coupling method
  71. Study on the evaluation method and application of logging irreducible water saturation in tight sandstone reservoirs
  72. Geochemical characteristics and genesis of natural gas in the Upper Triassic Xujiahe Formation in the Sichuan Basin
  73. Wehrlite xenoliths and petrogenetic implications, Hosséré Do Guessa volcano, Adamawa plateau, Cameroon
  74. Changes in landscape pattern and ecological service value as land use evolves in the Manas River Basin
  75. Spatial structure-preserving and conflict-avoiding methods for point settlement selection
  76. Fission characteristics of heavy metal intrusion into rocks based on hydrolysis
  77. Sequence stratigraphic filling model of the Cretaceous in the western Tabei Uplift, Tarim Basin, NW China
  78. Fractal analysis of structural characteristics and prospecting of the Luanchuan polymetallic mining district, China
  79. Spatial and temporal variations of vegetation coverage and their driving factors following gully control and land consolidation in Loess Plateau, China
  80. Assessing the tourist potential of cultural–historical spatial units of Serbia using comparative application of AHP and mathematical method
  81. Urban black and odorous water body mapping from Gaofen-2 images
  82. Geochronology and geochemistry of Early Cretaceous granitic plutons in northern Great Xing’an Range, NE China, and implications for geodynamic setting
  83. Spatial planning concept for flood prevention in the Kedurus River watershed
  84. Geophysical exploration and geological appraisal of the Siah Diq porphyry Cu–Au prospect: A recent discovery in the Chagai volcano magmatic arc, SW Pakistan
  85. Possibility of using the DInSAR method in the development of vertical crustal movements with Sentinel-1 data
  86. Using modified inverse distance weight and principal component analysis for spatial interpolation of foundation settlement based on geodetic observations
  87. Geochemical properties and heavy metal contents of carbonaceous rocks in the Pliocene siliciclastic rock sequence from southeastern Denizli-Turkey
  88. Study on water regime assessment and prediction of stream flow based on an improved RVA
  89. A new method to explore the abnormal space of urban hidden dangers under epidemic outbreak and its prevention and control: A case study of Jinan City
  90. Milankovitch cycles and the astronomical time scale of the Zhujiang Formation in the Baiyun Sag, Pearl River Mouth Basin, China
  91. Shear strength and meso-pore characteristic of saturated compacted loess
  92. Key point extraction method for spatial objects in high-resolution remote sensing images based on multi-hot cross-entropy loss
  93. Identifying driving factors of the runoff coefficient based on the geographic detector model in the upper reaches of Huaihe River Basin
  94. Study on rainfall early warning model for Xiangmi Lake slope based on unsaturated soil mechanics
  95. Extraction of mineralized indicator minerals using ensemble learning model optimized by SSA based on hyperspectral image
  96. Lithofacies discrimination using seismic anisotropic attributes from logging data in Muglad Basin, South Sudan
  97. Three-dimensional modeling of loose layers based on stratum development law
  98. Occurrence, sources, and potential risk of polycyclic aromatic hydrocarbons in southern Xinjiang, China
  99. Attribution analysis of different driving forces on vegetation and streamflow variation in the Jialing River Basin, China
  100. Slope characteristics of urban construction land and its correlation with ground slope in China
  101. Limitations of the Yang’s breaking wave force formula and its improvement under a wider range of breaker conditions
  102. The spatial-temporal pattern evolution and influencing factors of county-scale tourism efficiency in Xinjiang, China
  103. Evaluation and analysis of observed soil temperature data over Northwest China
  104. Agriculture and aquaculture land-use change prediction in five central coastal provinces of Vietnam using ANN, SVR, and SARIMA models
  105. Leaf color attributes of urban colored-leaf plants
  106. Application of statistical and machine learning techniques for landslide susceptibility mapping in the Himalayan road corridors
  107. Sediment provenance in the Northern South China Sea since the Late Miocene
  108. Drones applications for smart cities: Monitoring palm trees and street lights
  109. Double rupture event in the Tianshan Mountains: A case study of the 2021 Mw 5.3 Baicheng earthquake, NW China
  110. Review Article
  111. Mobile phone indoor scene features recognition localization method based on semantic constraint of building map location anchor
  112. Technical Note
  113. Experimental analysis on creep mechanics of unsaturated soil based on empirical model
  114. Rapid Communications
  115. A protocol for canopy cover monitoring on forest restoration projects using low-cost drones
  116. Landscape tree species recognition using RedEdge-MX: Suitability analysis of two different texture extraction forms under MLC and RF supervision
  117. Special Issue: Geoethics 2022 - Part I
  118. Geomorphological and hydrological heritage of Mt. Stara Planina in SE Serbia: From river protection initiative to potential geotouristic destination
  119. Geotourism and geoethics as support for rural development in the Knjaževac municipality, Serbia
  120. Modeling spa destination choice for leveraging hydrogeothermal potentials in Serbia
Sign up now to receive a 20% welcome discount
Institutional Access
How does access work?
Have an idea on how to improve our website?
Please write us.
© 2025 De Gruyter Brill
Downloaded on 11.9.2025 from https://www.degruyterbrill.com/document/doi/10.1515/geo-2022-0408/html
Scroll to top button