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Mechanism and timing of the Pliocene- Pleistocene foredeep migration in the Abruzzo Offshore area (Central Adriatic).
No full textSedimentology of the Section Peak Formation (Jurassic), Northern Victoria Land, Antarctica.
No full textAbstract: Models of Gondwana reconstruction agree in linking South Africa and Antarctica in Devonian to Triassic times, with an overall slow accumulation of shallow-water and alluvial deposits on a craton. In the Transantarctic Mountains, this sedimentary context, with the Gondwanide uplift, is well represented up to the Triassic by the rocks of the Beacon Supergroup; later similar alluvial deposition is recorded in northern Victoria Land (Priestley and Campbell Valleys) by the ‘Beacon-like’ sandstones of the Section Peak Formation, which interfingers with and is capped by basalt flows of the Ferrar Group. In this study, sedimentological observations of these sandstones, previously ascribed to the upper part of the Beacon Supergroup, are described.
The Section Peak Formation shows variously stratified alluvial facies associations with aeolian trough cross- bedding. Several sections have been measured and studied, leading to interpretations of the vertical evolution of the deposits, the lateral variations of the sedimentary environments and the provenance framework of clastic sediments and their palaeogeographical interpretation.
A sandy braided-stream environment is envisaged, composed of channels with dunes and foreset macroforms associated with both slip-faces and lee sides with descending dunes and rare plane beds. The abundance of thin sandstone beds with aeolian sedimentary structures indicates common aeolian reworking. Thicker sandstone bodies can be interpreted as the deposits of relatively persistent fluvial channels.
An aeolian environment, different from that described above, has been observed locally in the upper part of the area studied; large-scale, cross-bedded, fine-grained sandstones show foresets close to the angle of repose.
The palaeogeographical evolution, from Triassic to Middle Jurassic, indicates a low-gradient slope with mean- dering channels, grading into a more complex river system with braided streams (Section Peak Formation). Sandstone petrology proves that it drained mostly high-grade granulite-facies metamorphic and plutonic rocks of the basement (Wilson Terrane), but also intermittently reworked volcanic debris. These were eroded from coeval basaltic lava flows, erupted in the Section Peak basin during the initiation of lithospheric stretching, which preceded the Gondwana break-up
The sandstone of the Beacon Supergroup near Terra Nova Bay (Northern Victoria Land, Antarctica): preliminary results of facies and petrographic analyses.
No full textSandstone petrography of the Bowers Supergroup and Robertson Bay Group (Mariner Glacier area, Antarctica): preliminary report and remarks on paleotectonics.
No full textTectonic setting of the Plio - Pleistocene Periadriatic foredeep in the Abruzzo area (Italy)
No full textTectonic and sedimentary evolution of the Lower Pliocene Periadriatic foredeep in Central Italy.
No full textThe Periadriatic foredeep (Italy) was generated by Neogene downbending of the Adria Plate under the Apennine Chain. The basin is filled with Plio-Pleistocene siliciclastic turbidites. Its substratum consists of the carbonate succession of the southwestern Adria Plate margin. The influence of the basin’s morphology on sedimentation and subsequent tectonic evolution is investigated in the Abruzzo sector of the foredeep (Cellino Basin). The substratum is composed of Messinian evaporites that dip towards the Apennines (W). A NNW component along the depocentral axis is divided into four blocks with different depths. The substratum was also affected by a Messinian extensional fault system, not involving the overlying Pliocene sequence. This morphology controlled the distribution of the turbidites in the lower part of the Cellino Basin. The Plio-Pleistocene compressional deformation of the foredeep produced an inner complex structure (Internal Structure), involving the foredeep substratum and an outer imbricate thrust system (Coastal Structure), detached over the faulted Messinian evaporites. This thrust system is parallel to the extensional faults, suggesting a strong influence of the substratum morphology on the development of the compressional structures. The overall structural setting was validated with a balanced cross-section. Ou tof- sequence thrusting and non-coeval deformation within each thrust sheet characterize the local tectonic history
Sandstone composition of the Section Peak Formation (Beacon Supergroup, Northern Victoria Land, Antarctica) and relations with the Ferrar Group volcanics.
No full textCompressional tectonics overprinting extensional structures in the Abruzzo Periadriatic Foredeep (Central Italy) during Pliocene times
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