Kelasu Gr
Type Locality and Naming
It was named by Yao Guofan, Tao Ruiming in 1957. The naming locality is situated in the area stretching from Kuqa to Baicheng. Upward succession of the Ahe Fm, Yangisar Fm and Kezilenur Fm.
Synonym: （克拉苏群）
Lithology and Thickness
Lower part (the Ahe Fm) of the group is composed of grey-green pebbly sandstone with the developed cross-beddings, while its Middle and Upper parts (the Yangxia Fm and the Kezilesu Fm) are composed respectively of grey-green fine-grained sandstone, grey-black mudstone, carbonaceous shale and grey-white quartz-sandstone, intercalated with coal beds, with a total thickness of about 1700 m.
Relationships and Distribution
Lower contact
It is in a conformable contact with the underlying upper Triassic Talichik Fm (Taliqik Fm)
Upper contact
Regionally, the schematic strat column indicates the next younger unit as Sanjianfang Fm
Regional extent
The present group is distributed essentially on the northern margin of the Kuche Basin, namely in between the Taklake gully of the Kuche-Baicheng region and the Kezilenar gully, as well as in the area of Kurchu. In the areas of Takelake and Tugelming of Luntai County and Kezilenur of Kuche County the present group is intercalated with mineable coal beds, with scattered exposures of it being seen on the northeastern margin of the Tarim Basin or on the margin of the Kuruktag Mts. It is distributed only to the north of Robu Nor, with a thickness of 300-400 m. On the southern foothill of the Tianshan Mts the particular group is found to occur in such small-scale basins as the Taigelash and Yanqi Basins, also in the area north of the Bosteng Lake (Wushitara), as well as in the areas southwest (Tashdian), and east (Gancao Lake) of the Bosteng Lake, with the lithological salient features of the group being similar to those found in the Kuche area. The thickness of the particular group is of 2000 m.
GeoJSON
Fossils
It yields abundant plant and bivalve fossils.
Age
Depositional setting
The present group represents a set of fluvial and lacustrine-swamp deposits, containing coal and oil shale.
Additional Information