Abstract A coupled study of the kinematics of thrusting and hydrocarbon maturation has been carried out in the northern and central sub-Andean belt of Bolivia to define the petroleum potential of the area. In addition to the classic Devonian source rock (Tomachi-Tequeje formations to the north and Iquiri-Limoncito formations in the central area), two other source rock intervals are recognized: the Retama Formation (Upper Devonian-Lower Carboniferous) and the Copacabana Formation (Upper Carboniferous-Lower Permian). These are the most prospective units in northern Bolivia and are of marine origin. The structural style varies from north to south due to variations in the sedimentary column involved in the thrusts. The orogenic front was guided by the northern boundary of a Paleozoic sedimentary wedge. In the Boomerang area, this boundary is oriented obliquely to the regional shortening and controlled the development of a prominent transfer zone. To the north, the thrusts are wider and the amount of shortening increases. The western part of the northern sub-Andean zone is characterized by a very thick Tertiary piggyback basin fill. Two phases of hydrocarbon maturation are recognized. The first began in Early Carboniferous and affected mostly Devonian strata. Formation of structural traps during this period occurred rarely. The entire basin was then deeply eroded in Permian-Jurassic time, causing any hydrocarbons that may have formed to be lost. The second phase of maturation was contemporaneous with Andean deformation and with the resulting burial under the Tertiary cover in the foreland basin and in piggyback basins on thrust structures. The hydrocarbon expelled during this period may fill the Andean anticlines. The known source rocks are not proven to be gas prone, but current discoveries indicate a high gas to oil ratio that may be due to secondary cracking in the source rock. Because the initial potential of the source rocks is low, expulsion of heavy compounds is expected to be weak.

Abstract In the Devonian, the Falkland Islands were part of the high-latitude Cape Basin. West Falkland palynological assemblages are at a low thermal maturity level but also very low in diversity and dominated by simple spores with rare chitinozoans and acritarchs. The South Harbour Member contains rare verrucate and sculptured trilete spores, and is early Lochkovian. The Fish Creek Member palynofloras are late Lochkovian. The best correlative datum is the transgressive Fox Bay Formation where the palynological assemblage includes Ramochitina magnifica and is equivalent to the Sequence B transgression in Brazil (dated as late Pragian–earliest Emsian). The early Eifelian upper Fox Bay Formation spore assemblage is comparable to the Sequence C transgression in Brazil and the ?Choteč Event. The facies and position of the base Port Philomel Formation prasinophyte-rich black shale suggests the late Eifelian transgression (Kačák Event). Above this level is the inception of Geminospora lemurata (base Givetian). The upper Port Stanley Formation contains a late (but not latest) Famennian assemblage. Comparisons with both South Africa and South America indicate a number of correlative transgressive and regressive events that match to Euramerica. These correlations are at a continental scale and confirm eustatic control of these Devonian events.