Abstract We investigate the evolution of the Iberia–Newfoundland margin from Permian post-orogenic extension to Early Cretaceous break-up. We used a Quantitative Basin Analysis approach to integrate seismic stratigraphic interpretations and drill-hole data of two representative sections across the Iberia–Newfoundland margin with kinematic models for lithospheric thinning and subsequent flexural readjustment. We model the distribution of extension and thinning, palaeobathymetry, crustal structure, and subsidence and uplift history as functions of space and time. We start our modelling following post-orogenic extension, magmatic underplating and thermal re-equilibration of the Permian lithosphere. During the Late Triassic–Early Jurassic, broadly distributed, depth-independent lithospheric extension evolved into Late Jurassic–Early Cretaceous depth-dependent thinning as crustal extension progressed from distributed to focused deformation. During this time, palaeobathymetries rapidly deepened across the margin. Modelling of the southern and northern profiles highlighted the rapid development of crustal deformation from south to north over a 5–10 myr period, which accounts for the rapid change in Tithonian–Valanginian, deep- to shallow-water sedimentary facies between the Abyssal Plain and the adjacent Galicia Bank, respectively. Late-stage deformation of both margins was characterized by brittle deformation of the remaining continental crust, which led to exhumation of subcontinental mantle and, eventually, continental break-up and seafloor spreading.

Abstract Coastal exposures of Mesozoic sediments in the Wessex basin and Channel subbasin (southern UK), and the Lusitanian basin (Portugal) provide keys to the petroleum systems being exploited for oil and gas offshore Atlantic Canada. These coastal areas have striking similarities to the Canadian offshore region and provide insight to controls and characteristics of the reservoirs. Outcrops demonstrate a range of depositional environments from terrigenous and non-marine, shallow siliciclastic and carbonate sediments, through to deep marine sediments, and clarify key stratigraphic surfaces representing conformable and non-conformable surfaces. Validation of these analog sections and surfaces can help predict downdip, updip, and lateral potential of the petroleum systems, especially source rock and reservoir.

Abstract The Grand Banks of Newfoundland is a broad continental shelf that extends 450 km into the North Atlantic Ocean. A sequence of Mesozoic rift-events and subsequent break-ups associated with the North Atlantic rift are recorded in a series of complex basins. From the onset of exploration in the 1960’s, regional exploration on the Grand Banks has been primarily focused on the Early Cretaceous Ben Nevis and Hibernia formations shallow marine sandstone reservoirs. This early phase of exploration resulted in the discovery of the Hibernia, White Rose, and Hebron fields in the southern Jeanne d’Arc Basin. Collectively, these fields contain approximately 2.5 billion barrels of oil resources. The Terra Nova Field in the southern Jeanne d’Arc basin is the exception to this Early Cretaceous play trend, producing from Late Jurassic braided fluvial reservoirs (Jeanne d’Arc Formation) and contains approximately 500 million barrels of oil resources. This presentation is focused on recognizing and delineating a now proven petroleum system in the North Flemish Pass basin.

In eastern Canada, two periods of magmatism were associated with early Mesozoic continental rifting. Triassic dikes in southwest Nova Scotia and the Northumberland Strait F-25 well geochemically resemble alkaline dikes of the coastal New England (CNE) igneous province. Widespread Hettangian tholeiitic magmatism of the eastern North America (ENA) province is represented in eastern Canada by extensive multiple basalt flows around the Bay of Fundy and on the Scotian Shelf and Grand Banks and by several dikes hundreds of kilometers long. The total volume of observed Mesozoic magmatic products on the eastern Canadian margin is small. They were probably emplaced over relatively short time intervals, indicating the importance of tectonic pathways in permitting rise of magma to the surface. Samples from the CNE province and the Glooscap well on the west Scotian Shelf have more highly radiogenic Pb isotope compositions. Samples from southwestern Nova Scotia are enriched in LILE, and have higher Hf/Lu and lower Y/Nb compared with samples from Newfoundland and northern New Brunswick. Such geochemical trends are interpreted to result from the Permian-Triassic hotspot responsible for resetting of K-Ar dates and plutonic activity in New England. The progression from alkalic to tholeiitic magmatism through time is related to this plume. Other early Mesozoic basaltic rocks in eastern Canada have isotopic composition (low ɛ Nd and high 207 Pb/ 204 Pb) and trace element features (such as high La/Ta and low Ti/V) that reflect incorporation of crustal-type material in subcontinental mantle, perhaps by previous subduction. Geochemical comparison with Carboniferous tholeiites suggests that the early Mesozoic tholeiites have not been generally contaminated by continental crust, except for some local fluid phase interaction. The magmas resulted from adiabatic decompression of asthenosphere as a result of continental extension and subsequent plagioclase and pyroxene fractionation in mid-crustal reservoirs. Three major tectonic and igneous phases are distinguished: (1) Anisian to early Hettangian rifting, accompanied by minor alkalic dikes (CNE province), when basins formed by extension and were filled by thick terrigenous clastics and evaporites; (2) a postrifting phase (late Hettangian to Bajocian), separated by a postrift unconformity from underlying strata. This Hettangian unconformity is not a breakup unconformity. ENA magmatic activity (tholeiitic plateau basalts and linear composite dikes, up to 400 km landward of the hinge line) was localized along major deeply penetrating faults. The change in tectonic regime resulted in accelerated lithospheric attenuation accompanied by uplift landward of the hinge zone and an increase in subsidence seaward. (3) The final separation of continental crust and onset of oceanic rifting took place in the Bajocian and was accompanied by only limited igneous activity near the ocean-continent boundary.