The dasycladalean algae of the Plassen Carbonate Platform (Kimmeridgian-Early Berriasian) and the Barmstein Limestone (Late Tithonian): taxonomic inventory and palaeogeographical implications within the platform-basin-system of the Northern Calcareous Alp

Abstract The causes for the Middle to Late Jurassic tectonic processes in the Northern Calcareous Alps are still controversially discussed. There are several contrasting models for these processes, formerly designated “Jurassic gravitational tectonics”. Whereas in the Dinarides or the Western Carpathians Jurassic ophiolite obduction and a Jurassic mountain building process with nappe thrusting is widely accepted, equivalent processes are still questioned for the Eastern Alps. For the Northern Calcareous Alps, an Early Cretaceous nappe thrusting process is widely favoured instead of a Jurassic one, obviously all other Jurassic features are nearly identical in the Northern Calcareous Alps, the Western Carpathians and the Dinarides. In contrast, the Jurassic basin evolutionary processes, as best documented in the Northern Calcareous Alps, were in recent times adopted to explain the Jurassic tectonic processes in the Carpathians and Dinarides. Whereas in the Western Carpathians Neotethys oceanic material is incorporated in the mélanges and in the Dinarides huge ophiolite nappes are preserved above the Jurassic basin fills and mélanges, Jurassic ophiolites or ophiolitic remains are not clearly documented in the Northern Calcareous Alps. Here we present chrome spinel analyses of ophiolitic detritic material from Kimmeridgian allodapic limestones in the central Northern Calcareous Alps. The Kimmeridgian age is proven by the occurrence of the benthic foraminifera Protopeneroplis striata and Labyrinthina mirabilis, the dasycladalean algae Salpingoporella pygmea, and the alga incertae sedis Pseudolithocodium carpathicum. From the geochemical composition the analysed spinels are pleonastes and show a dominance of Al-chromites (Fe3+–Cr3+–Al3+ diagram). In the Mg/(Mg+ Fe2+) vs. Cr/(Cr+ Al) diagram they can be classified as type II ophiolites and in the TiO2 vs. Al2O3 diagram they plot into the SSZ peridotite field. All together this points to a harzburgite provenance of the analysed spinels as known from the Jurassic suprasubduction ophiolites well preserved in the Dinarides/Albanides. These data clearly indicate Late Jurassic erosion of obducted ophiolites before their final sealing by the Late Jurassic–earliest Cretaceous carbonate platform pattern.

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Anatomy of a synrift Jurassic pelagic carbonate platform and basin system, Rossa Mountains, Central Apennines, Italy: ABSTRACT

AAPG Bulletin ◽

10.1306/a25ffe77-171b-11d7-8645000102c1865d ◽

1994 ◽

Vol 78 ◽

Author(s):

Fabrizio Galluzzo, Massimo Santanto

Keyword(s):

Carbonate Platform ◽

Central Apennines ◽

Basin System

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Sequence stratigraphy of a Mesozoic carbonate platform-to-basin system in western Sicily

Open Geosciences ◽

10.2478/v10085-009-0021-8 ◽

2009 ◽

Vol 1 (3) ◽

Cited By ~ 3

Author(s):

Luca Basilone

Keyword(s):

Continental Margin ◽

Carbonate Platform ◽

Late Eocene ◽

Late Triassic ◽

Sedimentary Evolution ◽

Subaerial Exposure ◽

Platform Margin ◽

Western Sicily ◽

Physical Stratigraphy ◽

Basin System

AbstractSequence stratigraphic studies of the Triassic through Paleogene carbonate successions of platform, slope and basin in western Sicily (Palermo and Termini Imerese Mountains) have identified a sedimentary cyclicity mostly caused by relative oscillations of sea level. The stratigraphic successions of the Imerese and Panormide palaeogeographic domains of the southern Tethyan continental margin were studied with physical-stratigraphy and facies analysis to reconstruct the sedimentary evolution of this platform-to-basin system.The Imerese Basin is characterized by a carbonate and siliceous-calcareous succession, 1200–1400m thick, Late Triassic to Eocene in age. The strata display a typical example of a carbonate platform margin, characterized by resedimented facies with progradational stacking patterns. The Panormide Carbonate Platform is characterized by a carbonate succession, 1000–1200 m thick, Late Triassic to Late Eocene, mostly consisting of shallow-water facies with periodic subaerial exposure.The cyclic arrangement has been obtained by the study of the stratigraphic signatures (unconformities, facies sequences, erosional surfaces and stratal geometries) found in the slope successions. The recognized pattern has been compared with coeval facies of the shelf. This correlation provided evidence of sedimentary evolution, influenced by progradation and backstepping of the shelf deposits.The stratigraphic architecture of the platform-to-basin system is characterized by four major transgressive/regressive cycles during the late Triassic to late Eocene.These cycles, framed in a chronostratigraphic chart, allows the correlation of the investigated shelf-to-basin system with the geological evolution of the African continental margin during the Mesozoic, showing tectono-eustatic cycles. The first cycle, encompassing the late Triassic to early Jurassic, appears to be related to the late syn-rift stage of the continental margin evolution. The following three cycles, spanning from the Jurassic to Eocene, can be related to the post-rift evolution and to thermal subsidence changes.

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Neomeris mokragorensis sp. Nov. (Calcareous alga, Dasycladales) from the cretaceous of Serbia, Montenegro and the Northern calcareous Alps, (Gosau group, Austria)

Geoloski anali Balkanskog poluostrva ◽

10.2298/gabp0701039r ◽

2007 ◽

pp. 39-51 ◽

Cited By ~ 5

Author(s):

Rajka Radoicic ◽

Felix Schlagintweit

Keyword(s):

New Species ◽

Carbonate Platform ◽

Northern Calcareous Alps ◽

Northern Calcareous ◽

Calcareous Alga ◽

Gosau Group ◽

Mirdita Zone

The new species of the genus Neomeris - Neomeris mokragorensis sp. nov. described in this paper from western Serbia originates: from the Albian of Mokra Gora (the succession transgrading on the serpentinite) and from the Turonian of the Skrapez-Kosjeric area (the succession transgrading on the Carboniferous). The presence of this species has been noted in the Turonian of the Kukes and in the Santonian of the Metohija Cretaceous Unit (Mirdita Zone). In the surrounding of Podgorica (Dinaric Carbonate Platform, Montenegro), the same species previously was presented as Neomeris cf cretacea STEINMANN. Well preserved Neomeris specimens from the Turonian to the Santonian strata of the Northern Calcareous Alps (Gosau Group, Austria) previously described as Neomeris circularis BADVE & NAYAK, is assigned to Neomeris mokragorensis sp. nov. Neomeris mokragorensis is characterized by a thin loosed skeleton formed only around ampullae, by which, besides the form of the ampullae, this species is clearly distinct from Neomeris cretacea (Steinmann).

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Growth of carbonate platforms controlled by salt tectonics (Northern Calcareous Alps, Austria)

10.5194/egusphere-egu2020-11176 ◽

2020 ◽

Author(s):

Philipp Strauss ◽

Jonas Ruh ◽

Benjamin Huet ◽

Pablo Granado ◽

Josep Anton Muñoz ◽

...

Keyword(s):

Boundary Conditions ◽

Carbonate Platform ◽

Northern Calcareous Alps ◽

Rheological Parameters ◽

Basin Evolution ◽

Controlled Growth ◽

Carbonate Platforms ◽

Vienna Basin ◽

Northern Calcareous ◽

Salt Mines

<p>The Mid Triassic section of the Northern Calcareous Alps (NCA) is dominated by carbonate platforms, which grew diachronously on the Neo-Tethys shelf beginning in the Middle Anisian and ending in Lower Carnian times. The platforms grew isolated in previous deeper marine settings with high growth rates reaching 1.5 to 2 mm per year. The concept of self-controlled growth of carbonate systems on salt changes the understanding of Mid-Triassic NCA sedimentology. Conceptual models of the carbonate platform growth were done based on field observations, construction of cross-sections and subsidence analysis of selected carbonate mini-basins. To satisfy the observed boundary conditions of platforms growth in respect of timing, water depth and basin evolution, fast accumulation rates have to be assumed best represented by salt deflation and down-building of carbonate minibasins. A feedback loop of carbonate growth (creating a load gradient) and subsidence by salt evacuation initiates once the pre-kinematic layer reaches the sea level and the first layer of carbonate is produced. An initial phase of fast carbonate aggradation ends once the salt below the platform is fully evacuated and the minibasin is primary welded.</p><p>To further analyse and quantify boundary conditions necessary for the observed carbonate mini basin evolution, a series of thermo-mechanical numerical experiments were conducted. The density and rheological parameters for rock salt applied in the experiments were mainly gathered from observations and mechanical experiments on salt from salt mines and from an exploration well by OMV in the Vienna Basin. The numerical simulations essentially support the concept of down-building carbonate platforms. Self-controlled growth of carbonate systems on salt allows a completely new perspective to understand Mid-Triassic NCA carbonate platforms and their boundary conditions, such as the accumulation of thick carbonates (>1.5 km) without basement faulting, the isolated growth of platforms, or the transition of aggradational to progradational growth.</p>

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