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Poly-phased fluid flow in the giant fossil pockmark of Beauvoisin, SE basin of France

Authors :
Gay Aurélien
Favier Alexiane
Potdevin Jean-Luc
Lopez Michel
Bosch Delphine
Tribovillard Nicolas
Ventalon Sandra
Cavailhes Thibault
Neumaier Martin
Revillon Sidonie
Travé Anna
Bruguier Olivier
Delmas Doriane
Nevado Christophe
Source :
BSGF - Earth Sciences Bulletin, Vol 191, p 35 (2020)
Publication Year :
2020
Publisher :
EDP Sciences, 2020.

Abstract

The giant Jurassic-aged pockmark field of Beauvoisin developed in a 800 m wide depression for over 3.4 Ma during the Oxfordian; it formed below about 600 m water depth. It is composed of sub-sites organized in clusters and forming vertically stacked carbonate lenses encased in marls . This fine-scale study is focused on a detailed analysis of petrographical organization and geochemical signatures of crystals that grew up in early to late fractures of carbonate lenses, surrounding nodules, and tubes that fed them. The isotopic signature (C, O and Sr) shows that at least three different episodes of fluid migration participated to the mineralization processes. Most of the carbonates precipitated when biogenic seepage was active in the shallow subsurface during the Oxfordian. The second phase occurred relatively soon after burial during early Cretaceous and thermogenic fluids came probably from underlying Pliensbachian, Late Toarcian or Bajocian levels. The third phase is a bitumen-rich fluid probably related to these levels reaching the oil window during Mio-Pliocene. The fluids migrated through faults induced by the emplacement of Triassic-salt diapir of Propiac during the Late Jurassic and that remained polyphased drain structures over time.

Details

Language :
English, French
ISSN :
17775817
Volume :
191
Database :
Directory of Open Access Journals
Journal :
BSGF - Earth Sciences Bulletin
Publication Type :
Academic Journal
Accession number :
edsdoj.04c3ec47a38e4305ab36fcb813d3d01c
Document Type :
article
Full Text :
https://doi.org/10.1051/bsgf/2020036