Geochronology of volcanically associated hydrocarbon charge in the pre-salt carbonates of the Namibe Basin, Angola
Rochelle-Bates, N.; Roberts, N.M.W.; Sharp, I.; Freitag, U.; Verwer, K.; Halton, A.; Fiordalisi, E.; van Dongen, B.E.; Swart, R.; Ferreira, C.H.; Dixon, R.; Schröder, S.. 2021 Geochronology of volcanically associated hydrocarbon charge in the pre-salt carbonates of the Namibe Basin, Angola. Geology, 49 (3). 335-340. 10.1130/G48019.1
Before downloading, please read NORA policies.Preview |
Text (Open Access Paper)
335.pdf - Published Version Available under License Creative Commons Attribution 4.0. Download (4MB) | Preview |
Abstract/Summary
In volcanic rifted margins, the timing of hydrocarbon charge is difficult to predict, but is important in understanding fluid genesis. We investigated whether igneous activity was linked to hydrocarbon charge in the prolific South Atlantic pre-salt petroleum system. To do this, we applied in situ carbonate U-Pb geochronology, a relatively novel tool for dating hydrocarbon migration, to bituminous veins in pre-salt travertines from the rifted onshore Namibe Basin (Angola). To test if fluid flow was synchronous with known volcanic pulses, we also obtained new 40Ar/39Ar geochronology from a nearby volcanic complex. Bitumen is associated with calcite in a first generation of veins and vugs, and with dolomite in younger veins. The dated calcite veins yielded a pooled U-Pb age of 86.2 ± 2.4 Ma, which overlaps the volcanism 40Ar/39Ar age of 89.9 ± 1.8 Ma. The overlapping dates and the localized bitumen occurrence around the dated volcanic center show a clear genetic relationship between Late Cretaceous igneous activity and hydrocarbon charge. The dolomite was dated at 56.8 ± 4.8 Ma, revealing a previously unknown Paleocene/Eocene fluid-flow phase in the basin.
Item Type: | Publication - Article |
---|---|
Digital Object Identifier (DOI): | 10.1130/G48019.1 |
ISSN: | 0091-7613 |
Date made live: | 01 Apr 2021 14:41 +0 (UTC) |
URI: | https://nora.nerc.ac.uk/id/eprint/529999 |
Actions (login required)
View Item |
Document Downloads
Downloads for past 30 days
Downloads per month over past year