TY - JOUR

T1 - Early Kimmeridgian radiolarian fauna from the Sillenkopf Formation near Kronalalm and its evidence for the Late Jurassic geodynamic history of the Eastern Alps (Northern Calcareous Alps, Steinernes Meer, Germany)

AU - Diersche, Volker

AU - Suzuki, Hisashi

AU - Auer, Matthias

AU - Missoni, Sigrid

AU - Gawlick, Hans-Jürgen

PY - 2025

Y1 - 2025

N2 - Forty-eight well-preserved radiolarian species/morphotypes are reported from a siliceous limestone ofthe Kronalalm section in the Berchtesgaden National Park (Northern Calcareous Alps, Germany), whichelucidated an early Kimmeridgian age. The siliceous limestone is attributed to the Oxfordian–TithonianSillenkopf Formation of the upper part of the Ruhpolding Radiolarite Group in the Tirolic Nappe system.Facies comparisons of this Sillenkopf Formation outcrop are made 1) with the more basin-ward depositedtype sections of the Sillenkopf Formation and 2) with adjacent sections to the south, where an Oxfordian-Kimmeridgian basinal facies is missing due to intra-Upper Jurassic erosion. In those sections to thesouth, upper Kimmeridgian–Tithonian bituminous carbonates with intercalated polymictic mass-transportdeposits and bioclastic debris (Ledererkar Formation) were deposited in a slope-basin above an erosionalunconformity, directly on top of Lower Jurassic condensed red limestones. Our findings clearly evidencea today not anymore existing Late Jurassic carbonate platform south of today’s Northern Calcareous Alps,which shed its material northward into the Sillenkopf Basin.

AB - Forty-eight well-preserved radiolarian species/morphotypes are reported from a siliceous limestone ofthe Kronalalm section in the Berchtesgaden National Park (Northern Calcareous Alps, Germany), whichelucidated an early Kimmeridgian age. The siliceous limestone is attributed to the Oxfordian–TithonianSillenkopf Formation of the upper part of the Ruhpolding Radiolarite Group in the Tirolic Nappe system.Facies comparisons of this Sillenkopf Formation outcrop are made 1) with the more basin-ward depositedtype sections of the Sillenkopf Formation and 2) with adjacent sections to the south, where an Oxfordian-Kimmeridgian basinal facies is missing due to intra-Upper Jurassic erosion. In those sections to thesouth, upper Kimmeridgian–Tithonian bituminous carbonates with intercalated polymictic mass-transportdeposits and bioclastic debris (Ledererkar Formation) were deposited in a slope-basin above an erosionalunconformity, directly on top of Lower Jurassic condensed red limestones. Our findings clearly evidencea today not anymore existing Late Jurassic carbonate platform south of today’s Northern Calcareous Alps,which shed its material northward into the Sillenkopf Basin.

M3 - Article

JO - Early Kimmeridgian radiolarian fauna from the Sillenkopf Formation near Kronalalm and its evidence for the Late Jurassic geodynamic history of the Eastern Alps (Northern Calcareous Alps, Steinernes Meer, Germany)

JF - Early Kimmeridgian radiolarian fauna from the Sillenkopf Formation near Kronalalm and its evidence for the Late Jurassic geodynamic history of the Eastern Alps (Northern Calcareous Alps, Steinernes Meer, Germany)

ER -