Abstract
The main source rock (SR) of the Aquitaine Basin, the most important oil province in France, corresponds to organic-rich marine limestones of Upper Kimmeridgian age (Lons Formation in the Béarn area and Parnac Formation in the Quercy area). In order to better characterize their depositional environment, in particular the conditions of accumulation and preservation of organic-matter, a sedimentological, micropaleontological and geochemical study of the Crayssac section (Quercy) has been performed. Organic-rich sediments are argillaceous limestones (65 to 99% CaCO3) organized in repetitive beds of up to 1-m thickness. Their total organic matter content reaches up to 15 wt.%, and in this SR kerogen is type of II and immature. Microfauna content, the lack of barrier facies and the control of the wave action base over the depositional environments reflect deposition in an open marine type homoclinal ramp. Strong similarities with Kimmeridgian organic-rich limestones of the Middle East (Hanifa Formation) suggest that the Parnac Formation could act as an analogue of this prolific SR.
Translated title of the contribution | Sedimentary characterization of the carbonate source rock of Upper Kimmeridgian Parnac Formation of the Aquitaine Basin (Quercy area) |
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Original language | French |
Article number | 32 |
Pages (from-to) | 1-16 |
Number of pages | 16 |
Journal | Bulletin de la Socie´te´ Ge´ologique de France |
Volume | 188 |
Issue number | 5 |
Early online date | 15 Nov 2017 |
DOIs | |
Publication status | Published - 2017 |
Bibliographical note
The authors would like to thank Bertrand Fasentieux for the production of thin sections. We would like to express our gratitude to Dr. Alexander Brasier for his contribution to this manuscript. Olivier Ridet and Maryline Castello are acknowledged for their participation to field campaigns. We also thank Frank Haeseler, Claire Fialips and Pierre Hantzpergue for fruitful discussions. This manuscript greatly benefited from the remarks of two anonymous reviewers.Keywords
- Aquitaine Basin
- source rock
- upper Kimmeridgian
- Parnac Formation
- carbonates
- organic matter
- Bassin d’Aquitaine
- roche mère
- Kimméridgien supérieur
- Formation de Parnac
- matière organique