The University of Southampton
University of Southampton Institutional Repository
Warning ePrints Soton is experiencing an issue with some file downloads not being available. We are working hard to fix this. Please bear with us.

Dolomite formation within the methanogenic zone induced by tectonically driven fluids in the Peru accretionary prism

Dolomite formation within the methanogenic zone induced by tectonically driven fluids in the Peru accretionary prism
Dolomite formation within the methanogenic zone induced by tectonically driven fluids in the Peru accretionary prism
Early diagenetic dolomite formation in methanogenic marine sediments is enigmatic because acidification by CO2, a by-product of methanogenesis, should lead to carbonate dissolution and not precipitation. However, petrographic relationships indicate that dolomite breccia layers with {delta}13C values of ~+15{per thousand}, recovered from the lower slope of the Peru continental margin (Ocean Drilling Program Site 1230), formed deep in the methanogenic zone during tectonic activity of a décollement. Based on radiogenic Sr isotope ratios (87Sr/86Sr > 0.711) and positive {delta}18O values (+6{per thousand}), we present evidence that the dolomite breccias mainly formed from fluids originating from deep sedimentary units within the accretionary prism, where they interacted with continental crust and/or siliciclastic rocks of continental affinity. Due to silicate alteration and dehydration, such fluids are likely alkaline and thus have the potential to neutralize the acidification imposed by the high dissolved CO2 concentrations. This scenario provides a potential mechanism by which dolomite formation can be induced deep in a highly active methanogenic zone.
0091-7613
563-566
Meister, Patrick
0b137df2-0719-4946-9927-7ef2a846b206
Gutjahr, Marcus
5babbbc4-2a1a-48df-a2e3-d87b2483ea9c
Frank, Martin
09ec65ac-f62d-41da-86b2-81908973b8a1
Bernasconi, Stefano M.
d60685c9-9440-45e1-a27e-9e9e1c872082
Vasconcelos, Crisógono
461dc67a-ce2e-491e-b238-311f65d0a5c4
McKenzie, Judith A.
189620fe-2c4d-44b7-9c23-601bb3fb5a48
Meister, Patrick
0b137df2-0719-4946-9927-7ef2a846b206
Gutjahr, Marcus
5babbbc4-2a1a-48df-a2e3-d87b2483ea9c
Frank, Martin
09ec65ac-f62d-41da-86b2-81908973b8a1
Bernasconi, Stefano M.
d60685c9-9440-45e1-a27e-9e9e1c872082
Vasconcelos, Crisógono
461dc67a-ce2e-491e-b238-311f65d0a5c4
McKenzie, Judith A.
189620fe-2c4d-44b7-9c23-601bb3fb5a48

Meister, Patrick, Gutjahr, Marcus, Frank, Martin, Bernasconi, Stefano M., Vasconcelos, Crisógono and McKenzie, Judith A. (2011) Dolomite formation within the methanogenic zone induced by tectonically driven fluids in the Peru accretionary prism. Geology, 39 (6), 563-566. (doi:10.1130/G31810.1).

Record type: Article

Abstract

Early diagenetic dolomite formation in methanogenic marine sediments is enigmatic because acidification by CO2, a by-product of methanogenesis, should lead to carbonate dissolution and not precipitation. However, petrographic relationships indicate that dolomite breccia layers with {delta}13C values of ~+15{per thousand}, recovered from the lower slope of the Peru continental margin (Ocean Drilling Program Site 1230), formed deep in the methanogenic zone during tectonic activity of a décollement. Based on radiogenic Sr isotope ratios (87Sr/86Sr > 0.711) and positive {delta}18O values (+6{per thousand}), we present evidence that the dolomite breccias mainly formed from fluids originating from deep sedimentary units within the accretionary prism, where they interacted with continental crust and/or siliciclastic rocks of continental affinity. Due to silicate alteration and dehydration, such fluids are likely alkaline and thus have the potential to neutralize the acidification imposed by the high dissolved CO2 concentrations. This scenario provides a potential mechanism by which dolomite formation can be induced deep in a highly active methanogenic zone.

This record has no associated files available for download.

More information

Published date: June 2011

Identifiers

Local EPrints ID: 189883
URI: http://eprints.soton.ac.uk/id/eprint/189883
ISSN: 0091-7613
PURE UUID: f72feaad-ab28-4629-99b5-08c1cc27be76

Catalogue record

Date deposited: 07 Jun 2011 12:51
Last modified: 08 Nov 2021 19:19

Export record

Altmetrics

Contributors

Author: Patrick Meister
Author: Marcus Gutjahr
Author: Martin Frank
Author: Stefano M. Bernasconi
Author: Crisógono Vasconcelos
Author: Judith A. McKenzie

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×