HR: 1330h
AN: OS52A-0898    [PDF]
TI: The Upper Cretaceous Gosau Basins Of The Apuseni Mts./Romania; Basin Analysis, Provenance Analysis And Thermal History
AU: * Schuller, V
EM: volker.schuller@uni-tuebingen.de
AF: Volker Schuller, University of Tuebingen, Sigwartstr. 10, Tuebingen, 72074 Germany
AU: Frisch, W
EM: , wolfgang.frisch@uni-tuebingen.de
AF: Volker Schuller, University of Tuebingen, Sigwartstr. 10, Tuebingen, 72074 Germany
AB: The remnants of the Upper Cretaceous Gosau basins of the Apuseni Mts. record a similar sedimentary succession as the Gosau basins of the Eastern Alps: the Lower Gosau subgroup, represented by shallow marine sediments, and the Upper Gosau subgroup (turbiditic flysch and pelagic sediments). The controlling tectonic process of the Austroalpine Gosau basins is proposed to be subduction tectonic erosion, which led to the strong subsidence within these basins. Investigations on heavy minerals and the maturation of organic matter can help to understand the sudden subsidence which took place in Campanian/Maastrichtian time. The Lower Gosau subgroup reflects a predominantly metamorphic clastic source. In the Upper Gosau subgroup the metamorphic influence becomes less important. In some samples Chrome Spinel and Glaucophane has been identified. Both minerals in one assemblage show that a former accretional wedge with high-pressure rocks and obducted oceanic crust was eroded. The vitrinite reflectance data show a range of 0,8 to 1,8 % Rr within the Upper Cretaceous sequence. Increased coalification was measured close to large Banatitic and Neogene intrusions (up to 5.0 % Rr). For basin modeling, an erosion of 1600 m of Late Cretaceous sediments has been computed. Together with the measured and interpreted field data, the entire Gosau succession had a max. thickness of 2800 m. This thickness values are also reported from the Eastern Alps. Fission track dating was used to determine the age of the dedritic Zirkons. With this age-population-method a dynamic evolution of the hinterland concerning its exhumation and erosion can be modeled. Combined with models based on Apatit fission track length, a rapid uplift of the crystalline basement can be shown. All these results prove the similarity to the Gosau Basins of the Eastern Alps and the assumption that a direct connection to the Basins in the Apuseni Mts. existed during the Upper Cretaceous time. The main mechanism for the generating of the basins is inferred to be subduction errosion caused by a low-angle Benioff plane, an isostatic imbalance caused by the nappe stack produced during the collisional process and a simultaneous uplift of the crystalline basement.
DE: 8105 Continental margins and sedimentary basins
SC: Ocean Sciences [OS]
MN: 2003 Fall Meeting