An integrated study of Permo-Triassic basins along the North Atlantic passive margin: implication for future exploration

Abstract

Permo-Triassic rift basins offer important hydrocarbon targets along the Atlantic margins. Their fill is dominated by continental red beds, comprising braided fluvial, alluvial fan, aeolian, floodplain and lacustrine facies. These relatively lightly explored basins span both the Atlantic and Tethyan domains and developed above a complex basement with inherited structural fabrics. Sparse data in offshore regions constrain understanding of depositional geometries and sedimentary architecture, further impeded by their deep burial beneath younger strata, combined with the effects of later deformation during continental breakup. This paper provides results from a multidisciplinary analysis of basins along the Atlantic margin. Regional seismic and well data, combined with geochemical provenance analysis from the European North Atlantic margins, are integrated with detailed outcrop studies in Morocco and Nova Scotia. The research provides new insights into regional basin tectonostratigraphic evolution, sediment fill, and reservoir distribution, architecture and quality at a range of scales. Regional seismic profiles, supported by key well data, indicate the presence of post-orogenic collapse basins, focused narrow rifts and low-magnitude multiple extensional depocentres. Significantly, Permo-Triassic basin geometries are different and more varied than the overlying Jurassic and younger basins. Provenance analysis using Pb isotopic composition of detrital K-feldspar yields new and robust controls on the sediment dispersal patterns of Triassic sandstones in the NE Atlantic margin. The evolving sedimentary architecture is characterized by detailed sedi-mentological studies of key outcrops of age equivalent Permian-Triassic rifts in Morocco and Nova Scotia. The interplay of tectonics and climate is observed to influence sedimentation, which has significant implications for reservoir distribution in analogue basins. New digital outcrop techniques are providing improved reservoir models, and identification of key marker horizons and sequence boundaries offers a potential subsurface correlation tool. Future work will address source and seal distribution within the potentially petroliferous basins.

Microbes, mud and methane: cause and consequence of recurrent Early Jurassic anoxia following the end‐Triassic mass extinction

“…Palaeogeographic map of the E uropean E picontinental S eaway (modified after Redfern et al . ) showing main basins and sites mentioned in the text. NGB , north G erman B asin; SGB , south G erman B asin; CWB , C leveland– W essex B asin; PB , P aris B asin; LUX , L uxemburg; SJM , S wiss J ura M ountains; GCB , G rands C ausses B asin; BCB , B asque‐ C antabrian B asin; LB , L usitanian B asin.…”

Reconstructing Extensional Basin Architecture and Provenance in the Marrakech High Atlas of Morocco: Implications for Rift Basins and Inversion Tectonics

“…The High Atlas preserves two main rift‐related Triassic subbasin regions (Redfern et al, ): the Western High Atlas that includes the Argana Basin and offshore, and the MHA that includes multiple basins to the east (Tirknit, Tizi n'Test, Tizi n'Tacht‐Imlil, Setti‐Fadma, Oukaimeden‐Ourika, and Eç Çour; Domènech et al, ). These two subbasin regions are separated by the “Massif Ancien” basement uplift, which may have exerted control on the sediment provenance and dispersal patterns of the rift subbasins (Mattis, ; Petit & Beauchamp, ; Figure ).…”

Geometry and kinematics of the Triassic rift basin in Jameson Land (East Greenland)

“…The complexity of the Permian‐Triassic rift basins along the North Atlantic passive continental margin is influenced by the inherited basement framework [ Redfern et al ., ]. The inheritance of basement structural grain is widely considered to be an important factor in the structural development of the northwest European Atlantic margin that is somehow considered to follow the old Caledonian suture line [ Surlyk , ; Coward , ; Doré et al ., ].…”