In the sub-Alpine chains of Haut Provence, SE France, a very well-exposed Mesozoic sequence showing rapid thickness and facies changes associated with Jurassic and Cretaceous extension on the margin of the Ligurian Tethys has been deformed by ‘Alpine’ compression which occurred from the Late Cretaceous to the Pliocene. Although the geology has been very well known for decades, aspects of the structure remain enigmatic and cannot be explained by either Mesozoic extension or Alpine shortening alone. We infer that some deformation resulted from salt tectonics. A completely overturned, highly condensed Jurassic section near Barles village resembles the elevated roof of a Triassic salt body in a deep-marine basin. This carapace became overturned as a flap in the Middle Jurassic when salt broke out at the seafloor and overran the inverted flap as an allochthonous extrusion, comparable to those in the deepwater Gulf of Mexico or Angola. Later, Alpine compression exploited the weakness of the salt sheet as the Digne Thrust moved over the inverted flap. Although the flap is in the footwall of the thrust, evidence of soft-sediment deformation and other anomalous structures within the flap suggest that it did not originate as an overturned footwall syncline.

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The Guyana Basin formed during the Jurassic opening of the North Atlantic. The basin margins vary in tectonic origin and include the passive extensional volcanic margin of the Demerara Plateau in Suriname, an oblique extensional margin inboard at the Guyana-Suriname border, a transform margin parallel to the shelf in NW Guyana, and an ocean-ocean margin to the northeast which morphed from transform to oblique extension. Plate reconstructions suggest rifting and early seafloor spreading began with NNW/SSE extension (∼190-160Ma) but relative plate motion later changed to NW/SE. The fraction of magmatic basin floor decreases westwards and the transition from continental to oceanic crust narrows from 200km in Suriname to less than 50km in Guyana. The geometry and position of the onshore Takutu Graben suggest it formed a failed arm of a Jurassic triple junction that likely captured the Berbice river during post-rift subsidence and funneled sediment into the Guyana Basin. Berriasian to Aptian shortening caused crustal scale folds and thrusts in the NE margin of the basin along with minor inversions of basin margin and basin segmenting faults. Stratigraphically trapped Liza trend hydrocarbon discoveries are located outboard of inverted basement faults, suggesting a link between transform margin structure and their formation.