TY  - JOUR
A1  - Scheffler, Franziska
A1  - Immenhauser, Adrian
A1  - Pourteau, Amaury
A1  - Natalicchio, Marcello
A1  - Candan, Osman
A1  - Oberhänsli, Roland
T1  - A lost Tethyan evaporitic basin
BT  - Evidence from a Cretaceous hemipelagic meta-selenite - red chert association in the Eastern Mediterranean realm
JF  - Sedimentology : the journal of the International Association of Sedimentologists
N2  - Ancient evaporite deposits are geological archives of depositional environments characterized by a long‐term negative precipitation balance and bear evidence for global ocean element mass balance calculations. Here, Cretaceous selenite pseudomorphs from western Anatolia (‘Rosetta Marble’) — characterized by their exceptional morphological preservation — and their ‘marine’ geochemical signatures are described and interpreted in a process‐oriented context. These rocks recorded Late Cretaceous high‐pressure/low‐temperature, subduction‐related metamorphism with peak conditions of 1·0 to 1·2 GPa and 300 to 400°C. Metre‐scale, rock‐forming radiating rods, now present as fibrous calcite marble, clearly point to selenitic gypsum as the precursor mineral. Stratigraphic successions are recorded along a reconstructed proximal to distal transect. The cyclical alternation of selenite beds and radiolarian ribbon‐bedded cherts in the distal portions are interpreted as a two type of seawater system. During arid intervals, shallow marine brines cascaded downward into basinal settings and induced precipitation. During more humid times, upwelling‐induced radiolarian blooms caused the deposition of radiolarite facies. Interestingly, there is no comparable depositional setting known from the Cenozoic world. Meta‐selenite geochemical data (δ13C, δ18O and 87Sr/86Sr) plot within the range of reconstructed middle Cretaceous seawater signatures. Possible sources for the 13C‐enriched (mean 2·2‰) values include methanogenesis, gas hydrates and cold seep fluid exhalation. Spatially resolved component‐specific analysis of a rock slab displays isotopic variances between meta‐selenite crystals (mean δ13C 2·2‰) and host matrix (mean δ13C 1·3‰). The Cretaceous evaporite‐pseudomorphs of Anatolia represent a basin wide event coeval with the Aptian evaporites of the Proto‐Atlantic and the pseudomorphs share many attributes, including lateral distribution of 600 km and stratigraphic thickness of 1·5 to 2·0 km, with the evaporites formed during the younger Messinian salinity crisis. The Rosetta Marble of Anatolia may represent the best‐preserved selenite pseudomorphs worldwide and have a clear potential to act as a template for the study of meta‐selenite in deep time.
KW  - Blueschist metamorphism
KW  - depositional environment
KW  - evaporites
KW  - Neotethys
KW  - pseudomorphism
KW  - sedimentology
Y1  - 2019
U6  - https://doi.org/10.1111/sed.12606
SN  - 0037-0746
SN  - 1365-3091
VL  - 66
IS  - 7
SP  - 2627
EP  - 2660
PB  - Wiley
CY  - Hoboken
ER  -