Thrust sequence and syntectonic sedimentation in a piggy-back basin: the Oligo-Aquitanian Mula–Pliego Basin (Internal Betic Zone, SE Spain)
The Oligo-Aquitanian deposits of the Mula–Pliego basin consist of a marine carbonate platform assemblage (bottom), transitioning into a turbidite wedge (top). This evolution was controlled by tectonics in a piggy-back basin by means of three main mechanisms: first, a flexural tectonic event created the basin; later on, blind-fault-propagation folds deformed it progressively from south to north; finally a tectonic event destroyed the basin. To cite this article: M. Martin-Martin, A. Martin-Algarra, C. R. Geoscience 334 (2002) 363–370.
Is the northwestern Betic Cordillera mountain front active in the context of the convergent Eurasia–Africa plate boundary?
The present relief of the Betic‐Rif Cordillera has been mainly developed since the Late Miocene in the context of the Eurasia–Africa NW–SE oblique convergence and other interacting processes like slab roll‐back or delamination. However, seismicity distribution and field observations reveal that most of the external mountain front of the Betics is not clearly active at Present and tectonic activity is generally concentrated towards the innermost zones (Alborán Domain). New seismological data and recent faulting evidence from the northwesternmost front – the one best oriented with respect to the plate convergence – allow to discuss the present behaviour. Surface observations mainly indicate a N–S extensional tectonic regime, contrasting with the shallow reverse NW–SE compressive and the strike‐slip earthquake focal mechanisms. Altogether, these data suggest the activity of a tectonic wedge with top‐to‐the‐NW tectonic transport, bounded by a NW–SE transfer fault that separates the active western from the inactive eastern segments of the mountain front.
Observations Concerning the Relationship Between Stratigraphic Elements and Supranormal Pressures in the Alberta “Deep Basin” with Emphasis on Mesozoic Units
The hydrocarbon exploration require a detained understanding in foreland basins of the synchronous evolution between the foredeep and the forebulge: their lateral shifts may control either the size, the nature and the post depositional evolution of such good traps as carbonate buidups. This study describes the stepwise drowning of the Russian carbonate Platform located on the foreland margin of the prograding West Uralian foredeep during the Upper Paleozoic and the synchronous evolution of giant slope reef mounds. The Urals are a long, linear fold-thrust belt (2500 km long, 200 km wide and 1800 m high) at the boundary of Europe and Asia corresponding to the Upper Paleozoic suture of the Laurussian, Siberian and Kazakh cratons. The sedimentary cover of the Russian Platform that constitutes the Late Paleozoic foreland (Mid Carboniferous-Permian) of the Uralian fold belt is ca 3000 metres-thick. A typical section in the foreland basin exhibits from base to top: (1) deepening upward, wave-dominated to turbiditic carbonate ramp deposits from late Visean to Late Artinskian-Kungurian times bordered by slope reefs mounds from the Kasimovian and huge ones in the lower Permian. (2) shaly condensed section with volcaniclastics, radiolarites, glauconite and phosphorites, (3) shallowing upward section of polymictic turbidites ending to coarse-grained fan deltas, evaporites and meandering rivers red beds by the late Permian. Westward, towards the Russian Platform, the terrigenous deposits thin out, the carbonate ramps become lacunar and evolve towards emersion. Weathering and karstification processes are the rule. From the Kasimovian to early Artinskian four reef mounds end-members are recognised: (1)- Kasimovian- Ghzelian biostroms and banks, to 50 in made up of Paleoaplysina, phylloid algae, corals and bryozoans; Asselian-Sakmarian of Tubiphytes and Archaeolithoporella; (3)- Artinskian bioherms and banks, 10 50 thick, with bryozoans, Tubiphytes, sponges and brachiopods; (4)- Kungurian biostroms and with stromatolites. An integrated geological and hydrodynamic study of Mesozoic reservoirs in the deepest portion of the Alberta Basin illustrates the relationship between geological architecture and fluid types and pressures, contrasts the nature of regional fluid systematics within select units of economic importance and tests published models of fluid behavior in the Alberta Basin. Two Mesozoic (Jurassic Rock Creek Member/Niton Sandstone, Lower Cretaceous Viking Formation) intervals and one Paleozoic unit (Devonian Nisku Formation) are discussed. The main findings are: the