Zortashkol Limestone Fm
Period:
Cretaceous
Age Interval:
Berriasian – Hauterivian (K2), Z1
Province:
East Tajik (NE Pamir)
Type Locality and Naming
Synonym:
Reference section:
Lithology and Thickness
Limestone, sandstone, conglomerate at base. Thickness is 500-600 m.
Lithology Pattern:
Sandy limestone
Relationships and Distribution
Lower contact
The schematic stratigraphic column indicates the next formation is Silty limestone
Upper contact
Regional extent
This unit is part of the Eastern Pamir Plateau. The Zortashkol thrust sheet (sometimes called the Zortashkul nappe) lies in the Rangkul–Shorkul area, NE Tajikistan, not far from the Karakul basin.
GeoJSON
{"type":"Feature","geometry":{"type":"MultiPolygon","coordinates":[[[[73,38.6],[73.1,38.59],[73.18,38.65],[73.2,38.66],[73.31,38.69],[73.51,38.71],[73.52,38.59],[73.43,38.59],[73.38,38.56],[73.3,38.54],[73.26,38.55],[73.23,38.53],[73.19,38.54],[73.09,38.58],[72.99,38.59],[73,38.6]]]]}}
Fossils
fossil algae
Age
The stratigraphic age of the ~2.5 km thick strata of the Tuzguny-Terezki and Zortashkol thrust sheets - based on fossil algae is debated; Dronov et al. [2006] suggested a Meso-Neoproterozoic (Riphean) age; Vlasov et al. [1991] posited a Cambrian-Silurian age. The youngest detrital Zrn U-Pb age group of ~605 Ma in one sample supports the presence of Ediacaran strata. The Zortashkol thrust sheet contains >3 km of Silurian to Cretaceous strata. Strata that unconformably cover the Tuzguny-Terezki and Zortashkol thrust sheets were originally classi ed as Cretaceous and Paleogene [Yushin et al., 1964] but revised to Cretaceous by Vlasov et al. [1991]. Dronov et al. [2006] questioned all evidence for Paleogene deposits. (Rutte et al., 2017) Hence adjusted in Berriasian – Hauterivian for schematic stratigraphic column purpose.
Age Span:
Beginning stage:
Berriasian
Fraction up in beginning stage:
0.0
Beginning date (Ma):
143.10
Ending stage:
Hauterivian
Fraction up in the ending stage:
1.0
Ending date (Ma):
126.50
Depositional setting
Depositional pattern:
Additional Information
Compiler:
Extracted from Rutte, D., L. Ratschbacher, S. Schneider, K. Stübner, M. A. Stearns, M. A. Gulzar, and B. R. Hacker (2017), Building the Pamir-Tibetan Plateau—Crustal stacking, extensional collapse, and lateral extrusion in the Central Pamir: 1. Geometry and kinematics, Tectonics, 36, 342–384, doi:10.1002/2016TC004293.