Jurassic Oceanic Gateways of the North Atlantic

Jurassic rifting and breakup are still poorly understood in the North Atlantic region, particularly when considering that large swathes of NW Europe record the development of proto-oceanic gateways as early as the Late Triassic-Jurassic (Hesselbo et al., 2007). The first of these proto-oceanic gateways to form, and to effectively link the North and Central Atlantic regions, was the Iberia-Newfoundland gateway with its prolongation towards Ireland and the North Sea.
Following widespread evaporite deposition in the Late Triassic-earliest Jurassic, marine strata were first deposited during the Sinemurian in west Iberia. Black shales are developed episodically during the Pliensbachian-Toarcian and Oxfordian-Kimmeridgian. Outcrop and borehole data provide information on these periods of basinal deoxygenation in Iberia, southern UK, and in extended areas of the North Sea (Pereira and Alves, 2012). However, an integrated analysis of the petrophysical, geochemical and stratigraphic significance of ’North Atlantic’ black shale events is still to be undertaken to unravel the tectonic, climatic, and eustatic controls.
The project will use seismic, borehole and outcrop data from west Iberia, Southern UK and North Sea to investigate conditions in which Jurassic black shales formed. We aim to document at seismic, borehole and outcrop scales the occurrence (and distribution) of these black shale events and to understand the main local and regional controls on their generation, and at what time and length scales these operate.
The student will interpret a suite of 50+ boreholes from the region, tying stratigraphic and petrophysical information to 2D and 3D seismic data. In parallel, field analogues from the Lusitanian Basin (Portugal) and Wessex Basin (England) will be comprehensively studied and sampled. Data from these sites are necessary to correlate petrophysical, seismic and geochemical data at different scales, and to document the stratigraphic architecture of black shales.
Training in seismic interpretation will be provided using state-of-the-art Unix and PC workstations. Following a recent upgrade, Cardiff houses one of the most advanced seismic interpretation laboratories in Europe and the student will have access to leading edge computational facilities, namely Schlumberger’s Petrel@ and CGG-Veritas Hampson-Russell@ for petrophysical modelling and borehole interpretations.