Die Ober-Jura bis Unter-Kreide Schichtfolge des Gebietes Hoherstein-Sandling (Salzkammergut, Osterreich) - ImpSikationen zur Rekonstruk-tion des Block-Puzzles der zentralen Nordiichen Kaikalpen, der Glie-derung der Radiolaritflyschbecken und der Plas

摘要

The re-investigation of the late Middle Jurassic to Early Cretaceous sedimentary succession of the lloherstein plateau north of Altaussee including its basement and of the northern Sandling area has shown, that both the original palaeogeographic arrangement of the Middle to Late Jurassic radiolarite basins as well as the Late Jurassic Plassen carbonate platform in the central Salzkammergut area were destroyed by younger tectonism. At the Sandling in the south of the Hoher-stein plateau, the base below the Late Jurassic/Early Cretaceous shallow water carbonates is represented by cherty sediments of Callovian to Oxfordian age with intercalated polymict mass flow deposits containing clasts of the Hallstatt depositional realm (Triassic to Liassic), followed by pelagic micrites (Kimmeridgian to ?Tithonian) and transported reefal debris. The basal series of the Hoher-stein plateau is in contrast to this evolution. Below the Late Tithonian to Early/Middle Berriasian Barmstein limestones, reddish limestones (up to the Callovian/Oxfordian boundary) and cherty sediments with intercalated polymict mass flow deposits occur containing clasts deriving from the Late Triassic lagoon and its overlying series (= Tauglboden Basin, Oxfordian to Early Tithonian), followed by the Late Tithonian Oberalm Formation. Based on these new results, the today generally accepted palaeogeographic reconstructions of one basin in the central Salzkammergut area are discussed and reinterpreted: the sedimentary succession of the Hoherstein plateau is part of the Tauglboden Basin and can be correlated with the Lower Tirolic nappe, the sedimentary succession of the Sandling is part of the new defined Sandlingalm Basin. The Sandlingalm Basin is far traveled from the south and can be correlated with the Hallstatt Melange of the Upper Tirolic nappe. In the central Salzkammergut region the Trattberg-Rise as front of the advancing Upper Tirolic nappe and provenance area for the breccias and slides of the Tauglboden Basin is not more detectable in outcrops and is therefore eroded or overthrusted. The chapter plate tectonic model at the end summarizes the results in a reconstruction of the Middle Jurassic to Early Cretaceous geodynamic evolution and the genesis of the radiolaritic flysch basins and the Plassen carbonate platform.