Article
Licensed
Unlicensed Requires Authentication

Extreme channelization of fluid and the problem of element mobility during Barrovian metamorphism

  • EMAIL logo
Published/Copyright: April 2, 2015
Become an author with De Gruyter Brill
Author Information
American Mineralogist
From the journal American Mineralogist Volume 96 Issue 2-3

Abstract

Geochemical profiles across chemically altered zones (selvages) surrounding amphibolite facies quartz+kyanite veins were investigated to determine major, minor, and trace element mass transfer and volume strain due to channelized fluid flow. The three profiles are perpendicular to two veins cutting the Wepawaug Schist, Connecticut, U.S.A., which underwent Barrovian-style metamorphism during the Acadian orogeny. Selvages are highly aluminous with considerably more kyanite, staurolite, and garnet, and less quartz, plagioclase, and mica, than surrounding wallrocks. Kyanite crystals increase in size toward veins, and reach several centimeters in length within veins. Mass balance analysis indicates 50% silica loss and 34% volume loss from selvages, on average. Silica, transferred locally from selvages to veins, accounts for 40 to 80% of the vein silica; the remainder must have been precipitated from fluids that flowed through the veins during regional devolatilization. Fluid flow also transported elements into the rock mass, which were concentrated in the selvages. Gains of Fe, Mn, Y, and HREE were due to the growth of selvage garnet; Fe, Zn, and Li were sequestered into staurolite. Kyanite, staurolite, and garnet growth resulted in Al mass gains. Destruction of mica (particularly muscovite) and of plagioclase in the selvages resulted in losses of K, Na, Ba, Pb, Sn, and volatiles and losses of Na, Sr, and Eu, respectively. Thin Na and Sr enrichment zones associated with increased modal plagioclase are found along the margins between selvages and less altered wallrock and may represent either chemical self-organization produced during diffusive mass transfer and reaction, or are relics from a possible earlier period of Na enrichment in the selvages.

Simple, two-dimensional numerical modeling of flow in a fractured porous medium indicates that fluxes vary significantly over short distances (<1 m) adjacent to veins. Fluids, channelized into the high-permeability fracture conduits, carry the bulk of the fluid flow; mass transfer to and from selvages adjacent to the conduits occurred by some combination of diffusion and flow. In contrast, areas distal to the conduits are impoverished in fluid and undergo much more limited infiltration. As a consequence, different workers can come to vastly different conclusions about the magnitude of fluid fluxes and element transfer depending on the part of a fractured outcrop studied. This extreme spatial variability due to channelization can largely explain contrasting views that have arisen in the literature regarding the nature and intensity of non-volatile element mass transfer during Barrovian metamorphism. Determining “average” time-integrated fluid fluxes and levels of element transport across outcrops remains as important research challenges due to the spatial variability of flow.

Keywords: Fluid flow; metamorphism; Barrovian; veins; element mobility; modeling
Received: 2010-4-18
Accepted: 2010-10-10
Published Online: 2015-4-2
Published in Print: 2011-2-1

© 2015 by Walter de Gruyter Berlin/Boston

Articles in the same Issue

  1. Paulscherrerite from the Number 2 Workings, Mount Painter Inlier, Northern Flinders Ranges, South Australia: “Dehydrated schoepite” is a mineral after all
  2. Atomistic investigation of the pyrophyllitic substitution and implications on clay stability
  3. Application of the two-feldspar geothermometer to ultrahigh-temperature (UHT) rocks in the Khondalite belt, North China craton and its implications
  4. Wüstite in a hydrothermal silver-lead-zinc vein, Lucky Friday mine, Coeur d’Alene mining district, U.S.A.
  5. Gelosaite, BiMo6+(2–5x)Mo5+6xO7(OH)·H2O (0 ≤ x ≤ 0.4), a new mineral from Su Senargiu (CA), Sardinia, Italy, and a second occurrence from Kingsgate, New England, Australia
  6. Improved electron probe microanalysis of trace elements in quartz
  7. Ultra-high residual compressive stress (>2 GPa) in a very small volume (<1 μm3) of indented quartz
  8. Transmission electron microscopy investigation of Ag-free lillianite and heyrovskýite from Vulcano, Aeolian Islands, Italy
  9. Combined inelastic neutron scattering and solid-state density functional theory study of dynamics of hydrogen atoms in muscovite 2M1
  10. Contact metamorphism of a Cretaceous accretionary prism by the 14 Ma Okueyama granite, a single post-kinematic pluton in Central Kyushu, Japan: SVD analysis of metamorphic reactions and thermal release
  11. Origin of crosscutting dissolution surfaces in magmatic plagioclase
  12. Néel transition in (Mg,Fe)O: A possible change of magnetic structure
  13. Extreme channelization of fluid and the problem of element mobility during Barrovian metamorphism
  14. The high-temperature P21/m → C2/m phase transitions in synthetic amphiboles along the richterite–(BMg)–richterite join
  15. The crystal structure of barite, BaSO4, at high pressure
  16. Thermal decomposition of brushite, CaHPO4·2H2O to monetite CaHPO4 and the formation of an amorphous phase
  17. Rhombic-shaped nanodomains in columbite driven by contrasting cation order
  18. High-pressure structural evolution and equation of state of analbite
  19. In-situ dehydration studies of fully K-, Rb-, and Cs-exchanged natrolites
  20. The crystal structures and Raman spectra of aravaipaite and calcioaravaipaite
  21. Temperature dependence of the Fe2+ Mössbauer parameters in triphylite (LiFePO4)
  22. Synthesis and characterization of françoisite-(Nd): Nd[(UO2)3O(OH)(PO4)2]·6H2O
  23. Fluorphosphohedyphane, Ca2Pb3(PO4)3F, the first apatite supergroup mineral with essential Pb and F
  24. A new mineral with an olivine structure and pyroxene composition in the shock-induced melt veins of Tenham L6 chondrite
  25. The WURM project—a freely available web-based repository of computed physical data for minerals
  26. Acid production by FeSO4·nH2O dissolution: Comment
  27. Letter. Crystal chemistry of sodium in the Earth’s interior: The structure of Na2MgSi5O12 synthesized at 17.5 GPa and 1700 °C
  28. Letter. In-situ infrared spectra of OH in olivine to 1100°C
https://doi.org/10.2138/am.2011.3582
Keywords for this article
Fluid flow; metamorphism; Barrovian; veins; element mobility; modeling

Articles in the same Issue

  1. Paulscherrerite from the Number 2 Workings, Mount Painter Inlier, Northern Flinders Ranges, South Australia: “Dehydrated schoepite” is a mineral after all
  2. Atomistic investigation of the pyrophyllitic substitution and implications on clay stability
  3. Application of the two-feldspar geothermometer to ultrahigh-temperature (UHT) rocks in the Khondalite belt, North China craton and its implications
  4. Wüstite in a hydrothermal silver-lead-zinc vein, Lucky Friday mine, Coeur d’Alene mining district, U.S.A.
  5. Gelosaite, BiMo6+(2–5x)Mo5+6xO7(OH)·H2O (0 ≤ x ≤ 0.4), a new mineral from Su Senargiu (CA), Sardinia, Italy, and a second occurrence from Kingsgate, New England, Australia
  6. Improved electron probe microanalysis of trace elements in quartz
  7. Ultra-high residual compressive stress (>2 GPa) in a very small volume (<1 μm3) of indented quartz
  8. Transmission electron microscopy investigation of Ag-free lillianite and heyrovskýite from Vulcano, Aeolian Islands, Italy
  9. Combined inelastic neutron scattering and solid-state density functional theory study of dynamics of hydrogen atoms in muscovite 2M1
  10. Contact metamorphism of a Cretaceous accretionary prism by the 14 Ma Okueyama granite, a single post-kinematic pluton in Central Kyushu, Japan: SVD analysis of metamorphic reactions and thermal release
  11. Origin of crosscutting dissolution surfaces in magmatic plagioclase
  12. Néel transition in (Mg,Fe)O: A possible change of magnetic structure
  13. Extreme channelization of fluid and the problem of element mobility during Barrovian metamorphism
  14. The high-temperature P21/m → C2/m phase transitions in synthetic amphiboles along the richterite–(BMg)–richterite join
  15. The crystal structure of barite, BaSO4, at high pressure
  16. Thermal decomposition of brushite, CaHPO4·2H2O to monetite CaHPO4 and the formation of an amorphous phase
  17. Rhombic-shaped nanodomains in columbite driven by contrasting cation order
  18. High-pressure structural evolution and equation of state of analbite
  19. In-situ dehydration studies of fully K-, Rb-, and Cs-exchanged natrolites
  20. The crystal structures and Raman spectra of aravaipaite and calcioaravaipaite
  21. Temperature dependence of the Fe2+ Mössbauer parameters in triphylite (LiFePO4)
  22. Synthesis and characterization of françoisite-(Nd): Nd[(UO2)3O(OH)(PO4)2]·6H2O
  23. Fluorphosphohedyphane, Ca2Pb3(PO4)3F, the first apatite supergroup mineral with essential Pb and F
  24. A new mineral with an olivine structure and pyroxene composition in the shock-induced melt veins of Tenham L6 chondrite
  25. The WURM project—a freely available web-based repository of computed physical data for minerals
  26. Acid production by FeSO4·nH2O dissolution: Comment
  27. Letter. Crystal chemistry of sodium in the Earth’s interior: The structure of Na2MgSi5O12 synthesized at 17.5 GPa and 1700 °C
  28. Letter. In-situ infrared spectra of OH in olivine to 1100°C
Downloaded on 3.4.2026 from https://www.degruyterbrill.com/document/doi/10.2138/am.2011.3582/html
Scroll to top button