Abstract: Maturity and Thermal History of Sedimentary Basins in Austria

SACHSENHOFER, R.F., H.-J. GAWLICK, Ch. HASENHUTTL, G. RANTITSCH, and B. RUSSEGGER

We present a series of coalification maps based on vitrinite reflectance data of Paleozoic, Mesozoic and Tertiary sediments in Austria and adjacent areas. In addition organic maturation data and numeric modeling techniques are used to reconstruct the thermal histories of some sedimentary basins.

Only Tertiary basins are considered in this abstract. The coalification map of exposed Tertiary sediments is characterized by coalification maxima in Neogene sediments along the rims of metamorphic core complexes (Penninic Tauern and Rechnitz Windows), in the vicinity of early Miocene volcanoes (Styrian Basin), and in the vicinity of the Periadriatic Lineament (Slovenia).

The observed coalification pattern is mainly the result of the Miocene heat flow pattern. This was characterized by low heat flows along the northern margin of the Alps (e.g., 35 to 55 mW/m² in the Eastern Alpine foreland and the Vienna Basin region), a consequence of thickening of the crust, high sedimentation rates and Oligocene to Miocene thrusting. High heat flows occurred along the southeastern margin of the Alps in the Styrian Basin and the Slovenian part of the Pannonian Basin. These were a consequence of thinned crust beneath the Pannonian realm and of magmatic activity in the Styrian Basin and along the Periadriatic Lineament. Heat flows up to more than 300 mW/m² occurred above shallow magma chambers.

Elevated heat flows (up to 150 mW/m²) also occurred in the central Eastern Alps and at their eastern end, a consequence of rapid Miocene uplift of the Penninic core complexes. Extremely elevated vitrinite reflectance values close to the Rechnitz Window may indicate additional hydrothermal activity.

AAPG Search and Discovery Article #90942©1997 AAPG International Conference and Exhibition, Vienna, Austria