SRC, in association with IGI Limited, has recently completed the initial phases of the Eastern Atlantic Oceanic Crust Project (EAOCP). This long term exploration research study is investigating the occurrence and maturity of source rocks in the West African ‘Distal Domain’, and will include an investigation of the stratigraphic development, geochemistry, thermal and maturity history of source rocks as a guide to future exploration of the deep water basins overlying oceanic crust.
The overall objectives of the Eastern Atlantic Oceanic Crust Project are to investigate and elucidate the:
- main controls on stratigraphic development in the ‘Distal Domain’.
- controls/influences on the development and occurrence of organic-rich intervals (ORIs) i.e. global v regional v local, in the ‘Distal Domain’.
- occurrence/distribution of ORIs in the ‘Distal Domain’ along the West Africa Margin.
- potential of ORIs as commercial source rocks along the West Africa margin and the significance of OAEs.
- thermal history of sedimentary section overlying oceanic crust.
- maturity history of source rocks adjacent to the ‘landward limit of oceanic crust’ (LLOC) leading to a recognition of areas favourable for successful exploration on oceanic crust along the West Africa Margin.
- effects of oceanic crust deformation contributing to the formation of trap-forming structures.
The initial database compilation and review has been completed, with the creation of biostratigraphic and geochemical databases for interpretation as part of the research has been completed and is available to license from SRC. A technical seminar to present the interim results of the research study was held in London in July 2018, with presentations by SRC, IGI and Weston Stratigraphic project team. Selected slides from the seminar and details of interim deliverables of the research are available on request, please contact SRC.
A suitable seismic and potential field database connecting the ‘Distal Domain’ control points and extending from the control points to the proximal continental margin is ongoing. The seismic and potential field data will be used to:
- Further control the stratigraphy by seismic-stratigraphic interpretation and form the framework for the recognition and extrapolation of key ORIs/potential ‘drift’ source rocks.
- Constrain 1D (+ 2D) basin modelling away from the control points towards the LLOC.
- Further constrain the structural interpretation of the transitional-to-oceanic crustal zone.
- Integration of seismic and potential field data for modelling
- To investigate “reactivation structures”
New regional seismic data have shed light on crustal uplift, deformational history and structural geometry along the NW African passive margin, including new insights into oceanic crust deformation (OCD). As part of the Oceanic Crust project, SRC is undertaking a new thermal history study based on AFTA/VR from samples collected from DSDP holes over oceanic crust offshore Morocco. The regional Base Tertiary (‘Atlantis’) Unconformity (BTU) is penetrated by DSDP 397 where Miocene lies directly on Hauterivian sediments. The same unconformity can be seen clearly on new seismic data to the north and extends from stretched continental crust out over oceanic crust where it cuts deep down into the Cretaceous stratigraphy. Tying to the stratigraphy of DSDP holes 370, 415 & 416 gives a consistent Paleocene age for the oldest section above the unconformity with a significant time gap of 30 to 40 Ma. Further work, to incorporate the new AFTA/VR data, will be undertaken to better understand the nature of uplift and erosion and OCD along the Moroccan passive margin. Potentially the implications are critical for thermal history and petroleum systems analysis. This work will be presented at the PESGB-HGS Africa conference in London in early October 2019.
Collaboration with Geoex Limited
SRC cooperates with Geoex to help plan and promote Geoex’s various multi-client seismic projects. Our role has been to provide insights into the regional geology and prospectivity of the various areas in which Geoex has acquired multi-client 2D and 3D surveys and to assist Geoex in the promotion of the multi-client data and provision of data rooms for interested companies.