A1: Demise and aftermath of Triassic shallow-water carbonate ramps/platforms in the Western Tethys realm

3 days, 20-22 June 2020, Austria; Trip leaders: Missoni S.1, Gawlick H.J.1
1Montanuniversitaet Leoben, Austria
Contact: s.missoni@daad-alumni.de
Price: 490 EUR
Transportation: bus; Participants: Minimum 25, Maximum 50
Departure: Prague, Hotel Diplomat (5:00); Return: Prague, Hotel Diplomat
Includes: field trip guidebook, transportation, accommodation, breakfasts, lunch packets, snacks and dinners.
Degree of physical difficulty: Proper clothing and supplies are needed for the outdoors, mostly in mountainous areas (e.g., mountain boots, hat, wind breaker and sunscreen). Notify that it can be cold. The trip includes hiking in mountainous areas. Participants are advised to check local weather forecasts.
In the central Northern Calcareous Alps, the Triassic passive continental margin evolution of the Western Tethyan realm is characterized by the demise and aftermath of three shallow-water carbonate ramp/platform cycles. Beyond the siliciclastic dominated Early Triassic sedimentation, intense shallow-water carbonate production started around the Early/Middle Triassic boundary, deposited first under restricted and later under more open-marine conditions. The Late Anisian break-up of the Neo-Tethys Ocean led to the drowning of this shallow-water ramp. In the Late Ladinian shallow-water carbonates re-established and resulted in the complex Ladinian to early Carnian platform - basin pattern. Later in the Carnian, after the partial drowning of this platform by siliciclastic input the shallow-water carbonate production restarted and established the huge Norian Hauptdolomit/Dachstein Carbonate Platform with its classical lagoonal sediments, reef belt, and its transition to the open shelf area. In the Rhaetian the carbonate factories were influenced by siliciclastic input, forming a deep lagoon. At the Triassic/Jurassic-boundary shallow-water carbonate production ended, the platform drowned. Beside all sedimentological features, controlling factors of platform demise can be discussed as ocean acidification, climate changes, stepwise mass extinctions and sea-level fluctuations.
Left: View on the Dachstein Glacier, type locality of the Dachstein Formation; Right: Megalodon limestone in Lofer facies.
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