Molecular indicators of palaeosalinity and depositional environment of small scale basins within carbonate platforms: The Late Triassic Hauptdolomite Wiestalstausee section near Hallein (Northern Calcareous Alps, Austria)

2007 ◽  
Vol 38 (1) ◽  
pp. 92-111 ◽  
Author(s):  
A. Bechtel ◽  
H.-J. Gawlick ◽  
R. Gratzer ◽  
M. Tomaselli ◽  
W. Püttmann
Keyword(s):  
Depositional Environment ◽  
Northern Calcareous Alps ◽  
Late Triassic ◽  
Small Scale ◽  
Carbonate Platforms ◽  
Northern Calcareous ◽  
Molecular Indicators

scholarly journals Dachstein-type Avroman Formation: An indicator of the Harsin Basin in Iraq

GeoArabia ◽  
2015 ◽  
Vol 20 (4) ◽  
pp. 17-36
Author(s):  
Agoston Sasvari ◽  
Laura Davies ◽  
Andrew Mann ◽  
Jawad Afzal ◽  
Gabor Vakarcs ◽  
...  
Keyword(s):  
Depositional Environment ◽  
Carbonate Platform ◽  
Tectonic Setting ◽  
Upper Triassic ◽  
Northern Calcareous Alps ◽  
Late Triassic ◽  
Northern Calcareous ◽  
Marine Sedimentation ◽  
Tectonic Position ◽  
Arabian Platform

ABSTRACT A field survey was carried out in 2012 focusing on the tectonic position and the role of Upper Triassic (Upper Norian–Rhaetian) Avroman Formation outcrops located in the Zalm area of Iraq, close to the Iraq-Iran border. At this location, the Cretaceous chert-bearing strata of the Qulqula Formation are overlain by sheared mafic bodies, which are in turn topped by the cliffs of the megalodontaceae-bearing Upper Triassic Avroman Formation. Similarities in lithology, sequence and tectonics position, suggest that the Triassic section of the Bisotoun Unit from the Kermanshah Zone of Iran can be used as a tectonic analogue of the Avroman Formation. According to our model, both the Avroman and the Bisotoun units formed an intra-oceanic carbonate platform, built-up by a characteristic megalodontaceae-bearing carbonate platform assemblage during the Late Triassic. The Harsin oceanic basin, which separated the Avroman-Bisotoun Platform from the Arabian Platform, was characterised by deep-marine sedimentation, the remnants of which form the Qulqula Formation in Iraq, and the Radiolaritic Nappe and the Harsin Mélange in the Kermanshah Zone. This tectonic setting is not unique; numerous authors suggest the existence of an oceanic rim basin, separating carbonate platform units (e.g. Oman ‘exotics’) from the Arabian Platform. The age of the deformation could be Late Cretaceous (Maastrichtian), but using analogues from Iran, a Palaeogene deformation also seems possible. The Avroman Formation was interpreted to be a Dachstein-type sediment, similar to the well-studied Dachstein Formation of the Northern Calcareous Alps, Austria. Rock units, with similar lithology, or identical depositional environment and macroscopic fauna, were described by numerous authors along the Neo-Tethys suture zone from Austria to Japan, and from several tectonic units along the Panthalassa margin. The implication of this correlation is important for future studies: using well-described type localities of the marine units from the Northern Calcareous Alps as a reference, it is possible to significantly extend the available background knowledge, and to gain better insight into the Triassic regional depositional environment of the Middle East.

Taxonomic affinities and paleogeography of Stromatomorpha californica Smith, a distinctive Upper Triassic reef-adapted demosponge

2009 ◽  
Vol 83 (5) ◽  
pp. 783-793 ◽  
Author(s):  
B. Senowbari-Daryan ◽  
G. D. Stanley
Keyword(s):  
North America ◽  
Shallow Water ◽  
Type Species ◽  
Upper Triassic ◽  
Northern Calcareous Alps ◽  
Late Triassic ◽  
Separate Species ◽  
Northern Calcareous ◽  
Siliceous Spicules ◽  
Horizontal Layers

Stromatomorpha californica Smith is a massive, calcified, tropical to subtropical organism of the Late Triassic that produced small biostromes and contributed in building some reefs. It comes from the displaced terranes of Cordilleran North America (Eastern Klamath terrane, Alexander terrane, and Wrangellia). This shallow-water organism formed small laminar masses and sometimes patch reefs. It was first referred to the order Spongiomorphidae but was considered to be a coral. Other affinities that have been proposed include hydrozoan, stomatoporoid, sclerosponge, and chambered sponge. Part of the problem was diagenesis that resulted in dissolution of the siliceous spicules and/or replaced them with calcite. Well-preserved dendroclone spicules found during study of newly discovered specimens necessitate an assignment of Stromatomorpha californica to the demosponge order Orchocladina Rauff. Restudy of examples from the Northern Calcareous Alps extends the distribution of this species to the Tethys, where it was an important secondary framework builder in Upper Triassic (Norian-Rhaetian) reef complexes. Revisions of Stromatomorpha californica produce much wider pantropical distribution, mirroring paleogeographic patterns revealed for other tropical Triassic taxa. Review of Liassic material from the Jurassic of Morocco, previously assigned to Stromatomorpha californica Smith var. columnaris Le Maitre, cannot be sustained. Species previously included in Stromatomorpha are: S. stylifera Frech (type species, Rhaetian), S. actinostromoides Boiko (Norian), S. californica Smith (Norian), S. concescui Balters (Ladinian-Carnian), S. pamirica Boiko (Norian), S. rhaetica Kühn (Rhaetian), S. stromatoporoides Frech, and S. tenuiramosa Boiko (Norian). Stromatomorpha rhaetica Kühn described from the Rhaetian of Vorarlberg, Austria shows no major difference from S. californica. An example described as S. oncescui Balters from the Ladinian-Carnian of the Rarau Mountains, Romania, is very similar to S. californica in exhibiting similar spicule types. However, because of the greater distance between individual pillars, horizontal layers, and the older age, S. oncescui is retained as a separate species. The net-like and regular skeleton of Spongiomorpha sanpozanensis Yabe and Sugiyama, from the Upper Triassic of Sambosan (Tosa, Japan), suggests a closer alliance with Stromatomorpha, and this taxon possibly could be the same as S. californica.

scholarly journals Development of early calcareous nannoplankton in the late Triassic (Northern Calcareous Alps, Austria)

2020 ◽  
Vol 193 ◽  
pp. 103254
Author(s):  
Isaline Demangel ◽  
Zsófia Kovács ◽  
Sylvain Richoz ◽  
Silvia Gardin ◽  
Leopold Krystyn ◽  
...  
Keyword(s):  
Northern Calcareous Alps ◽  
Late Triassic ◽  
Calcareous Nannoplankton ◽  
Northern Calcareous

scholarly journals Deep-water ostracods from the Middle Anisian (Reifling Formation) of the Northern Calcareous Alps (Austria)

2015 ◽  
Vol 34 (1) ◽  
pp. 71-91 ◽  
Author(s):  
Wolfgang Mette ◽  
Avi Honigstein ◽  
Sylvie Crasquin
Keyword(s):  
New Species ◽  
Deep Water ◽  
Depositional Environment ◽  
Middle Triassic ◽  
Taxonomic Composition ◽  
Northern Calcareous Alps ◽  
Northern Calcareous ◽  
First Time ◽  
Neritic Species

Abstract. A diverse silicified ostracod aassemblage from Middle Anisian, Middle Triassic, intra-shelf basin deposits (Reifling Formation) is described. It comprises 32 species, of which 5 are new species (Bairdia biforis n. sp., B. schneebergiana n. sp., Mirabairdia praepsychrosphaerica n. sp., M. plurispinosa n. sp., Bairdiacypris aequisymmetrica n. sp.). The assemblage consists of both neritic species and deep-water taxa which have been considered as representatives of the ‘Thuringian Ecotype’ or the ‘Palaeopsychrospheric Fauna’. Lithofacies, palaeogeographical setting and taxonomic composition are suggestive of a deep neritic to upper bathyal depositional environment. ‘Archaic’ faunal elements are relatively rare and include the genera Spinomicrocheilinella and Processobairdia, which were formerly known only from the Palaeozoic and are now recorded for the first time from the Mesozoic.

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

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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