Methane-Derived High-Mg Calcite Submarine Cement in Holocene Nodules from the Fraser Delta, British Columbia, Canada
- Maurice E. Tucker2,
- Robin G. C. Bathurst3
Published Online: 29 APR 2009
DOI: 10.1002/9781444304510.ch7
Copyright © 1990 The International Association of Sedimentologists
Book Title
Carbonate Diagenesis
Additional Information
How to Cite
Nelson, C. S. and Lawrence, M. F. (2009) Methane-Derived High-Mg Calcite Submarine Cement in Holocene Nodules from the Fraser Delta, British Columbia, Canada, in Carbonate Diagenesis (eds M. E. Tucker and R. G. C. Bathurst), Blackwell Publishing Ltd., Oxford, UK. doi: 10.1002/9781444304510.ch7
Editor Information
- 2
Department of Geological Sciences, University of Durham, UK
- 3
Derwen Deg Fawr, Llanfair DC, Ruthin, Clwyd, North Wales, UK
Publication History
- Published Online: 29 APR 2009
- Published Print: 21 AUG 1990
ISBN Information
Print ISBN: 9780632029389
Online ISBN: 9781444304510
- Summary
- Chapter
Keywords:
- methane-derived high-Mg calcite submarine cement in Holocene nodules from Fraser Delta;
- carbonate nodules and slabs in late Holocene shelly terrigenous deposits;
- methane-derived Mg-calcite;
- microbiological degradation of organic matter in deltaic deposits;
- anaerobic bacterial fermentation
Summary
Carbonate nodules and slabs in late Holocene shelly terrigenous deposits of the modern Fraser River delta (∼ 49°N) are formed close to the seafloor by precipitation from saline pore waters of mainly fibrous to bladed crystals of high-Mg (∼ 10–20 mol% MgCO3) calcite cement as coalescing isopachous crusts on grains. Previous reports that the cement is low-Mg calcite are not supported by this study. Highly negative δ13C values of −7 to −59‰ for the cements indicate that the bulk of their carbonate carbon was derived from the microbiological degradation of organic matter in the deltaic deposits during shallow burial. In particular, the production of biogenic methane (CH4) by anaerobic bacterial fermentation, its upward migration, chemical or biological oxidation to CO2 and neutralization in the near-surface sediment, and diffusion to microenvironments relatively enriched in organic components, are a possible set of conditions influencing the process and sites of carbonate cementation. Methane-derived Mg-calcite appears also to be the major submarine cement in several other modern occurrences of lithified shallow-water terrigenous sands and muds at non-tropical latitudes.