Querquek Fm
Type Locality and Naming
The type section is in the east segment of Querquek Mountain, Xinjiang (88°18′50″E, 40°54′50″N), Toli County, Xinjiang. The Querquek Fm was named by Norin (1937).
The Querquek Fm had previously been referred to the Ordovician in west part of the northeastern Tarim. No.1 Team of No.13 Party of Geology (1957) restricted the Querquek Fm to the carbonate rock yielding cephalopod Sinoceras chinense in the vicinity of the Xidashan, which was renamed the Wuligeztag Fm by the Xinjiang Compiling Group for Regional Stratigraphic Scale (1981). At the same time, the Xinjiang Compiling Group for Regional Stratigraphic Scale (1981) divided the Ordovician in Querquek into Xiangguletag Fm, Querquek Fm and Wuligeztag Fm, in ascending order. Because the difference in Ordovician lithology in the southern part and the northern part of the Kuruktag, Lai et al. (1982) considered the Ordovician in the northern part as the Querquek Gr. In 1979-1981, Xinjiang Party of Regional Geological Survey found a clastic sequence equivalent to the Linxiagnian-Wufengian sediments of South China in Querqueke-Nanyadang Hill, which was named the Wuligeztag Fm by Xiao Bing (1990) and the Yuanbaoshan Fm by Zhong Rui et al. (1990). Considering its lithology and fauna similar to those of the Querquek Fm, the present book includes the clastic sequence in the Querquek Fm. And the previously defined Xiangguletag Fm is maintained in this book due to its different lithology from the Querquek Fm.
Synonym: (却尔却克组); Charchaq Fm (spelling)
Lithology and Thickness
The Querquek Fm is divided into two parts. The lower part is 650-960 m thick, and is composed of interbedded mudstone, siltstone, sandstone and limestone; the upper part is characterized by a 1000 m thick flyschiod sequence of sandstone, siltstone and silty mudstone.
Relationships and Distribution
Lower contact
With a covered lower boundary. Regionally, the next older unit is the Xiangguletag Fm of early Ordovician, or the Torsuqtagh Fm of late Cambrian.
Upper contact
The Querquek Fm is disconformably overlain by the Lower Silurian (Tuxbulak Fm)
Regional extent
The Querquek Fm is exposed in Querquek Hill and Yuanbao Hill in south part of Kuruktag.
GeoJSON
Fossils
It yields graptolite, trilobite and cephalopod. The graptolite fauna includes Undulograptus austrodentatus assemblage, Amplexograptus confertus assemblage, Pterograptus elegans assemblage, Glossograptus hincksii assemblage, Nemagraptus gracilis assemblage, Climacograptus (D.) bicornis assemblage, Climacograptus (D.) spiniferus assemblage, Orthograptus quadrimucronatus assemblage and Dicellograptus complanatus assemblage, in ascending order (Zhou Zhiyi et al., 1990; Wang Pu et al., 1992).
Age
Depositional setting
It represents deeper marginal basin to submarine fan environment. The upper part is flysch.
Additional Information