Silicate–Carbonate Reactions in Sedimentary Systems: Fluid Composition Control and Potential for Generation of Overpressure

  1. Richard H. Worden3 and
  2. Sadoon Morad4
  1. I. Hutcheon1 and
  2. S. Desrocher2

Published Online: 17 MAR 2009

DOI: 10.1002/9781444304336.ch8

Clay Mineral Cements in Sandstones

Clay Mineral Cements in Sandstones

How to Cite

Hutcheon, I. and Desrocher, S. (1999) Silicate–Carbonate Reactions in Sedimentary Systems: Fluid Composition Control and Potential for Generation of Overpressure, in Clay Mineral Cements in Sandstones (eds R. H. Worden and S. Morad), Blackwell Publishing Ltd., Oxford, UK. doi: 10.1002/9781444304336.ch8

Editor Information

  1. 3

    Department of Earth Sciences, University of Liverpool, Brownlow Street, Liverpool L69 3GP, UK

  2. 4

    Department of Earth Sciences, Uppsala University, Villa vägen 16, S-752 36 Uppsala, Sweden

Author Information

  1. 1

    Geology and Geophysics, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N IN4, Canada

  2. 2

    Golder and Associates, 2180 Meadowvale Blvd., Mississauga, Ontario L5N 5S3, Canada

Publication History

  1. Published Online: 17 MAR 2009
  2. Published Print: 7 OCT 1999

ISBN Information

Print ISBN: 9781405105873

Online ISBN: 9781444304336

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Keywords:

  • silicate–carbonate reactions in sedimentary systems;
  • silicate–carbonate reactions - in hydrothermal and sedimentary systems;
  • hydrogen from organic reactions and pH;
  • silicate–carbonate reactions and overpressure;
  • silicate–carbonate reactions - potential source of overpressure

Summary

Silicate–carbonate reactions have been identified as probable controls on two trends of Pmath image and temperature, one observed in sedimentary basins and the other in geothermal fluids associated with mafic volcanic rocks. These trends probably reflect equilibrium between the fluids and silicate–carbonate minerals, primarily clay minerals and feldspars in sediments, and clay minerals, feldspars, zeolites and zoisite in mafic rocks. Silicate–carbonate mineral reactions have been identified as pH buffering systems with the capacity to set pH in organic acid-bearing waters, but it is possible that hydrogen released by organic maturation reactions also could influence pH and lead to development of secondary porosity. Computer simulation of these processes suggests that hydrogen from such reactions would have to be highly focused by fluid flow to develop significant porosity in pH buffered silicate–carbonate systems or in unbuffered carbonate rock systems. Silicate–carbonate reactions can lead to the formation of a free vapour phase containing CO2. Potentially, continued progress of such reactions could lead to pressures above hydrostatic (overpressure). Simulations based on silicate–carbonate reactions observed in sedimentary basins suggest that these reactions could account for as much as a 77% increase in hydrostatic pressure. The transfer of CO2 from a carbonate mineral phase, when present, to the gas phase by silicate–carbonate reactions could be a previously unrecognized mechanism for the generation of overpressure during progressive burial of siliciclastic sand and shale.