Kensay Fm
Type Locality and Naming
No type section was assigned originally when the Kensay Formation was proposed, either by the above-mentioned Joint Team or by Cheng (1979). An auxiliary section, the Kendaketas XXXIII section, Huocheng County, Xinjiang Uygur Autonomous Region, was proposed by Cai (1999) as representative section of the formation (80°54’40”E, 44°31’35”N). The section lies about 53 km north of the seat of Huocheng County, Xinjiang Uygur Autonomous Region and was measured by the No. 6 Brigade of the Second Regional Geological Survey Team of Xinjiang Bureau of Geology in 1988. The Kensay Formation was first published by Cheng (1979). The name is derived from Kensaysi Mountain Pass in Houcheng County, Ili Kazak Autonomous Prefecture, Xinjiang Uygur Autonomous Region. The name was originally appeared a 1974 manuscript by the Joint Team of the Institute of Geology, Chinese Academy of Geological Sciences, and the Stratigraphic Brigade of the Second Regional Geology Survey Team of Xinjiang Uygur Autonomous Region.
Synonym: （肯萨依组）; Based on the biostratigraphic contents, Wang and Cheng (1985) named the middle part and the upper part of the Kensay Formation as Akqat Fm and Jiangjungou Fm respectively, both of which are forms of lithological units with biostratigraphic meanings. To return to the property of lithological unit, Cai (1999) merged the Akqat and the Jiangjungou formations back into the Kensay Formation.
Lithology and Thickness
The Kensay Formation is a clastic sequence with minor interbeds of carbonate rocks. It consists of dark grey to black, thin-bedded siliceous and argillaceous siltstone, siltstone, clastic sandstone, intercalated with limestone and sandy limestone, and with phosphoric siliceous rock and siltstone at the base.
Relationships and Distribution
Lower contact
The Kensay Fm is commonly in disconformable in conformable contact with the underlying Linkuanggou Fm or in in a few of cases in conformable contact with the latter formation. The lower boundary of the Kensay Fm is defined by lithologic change from the limestone of the Linkuanggou Fm to the shale at the base of the Kensay Fm.
Upper contact
It is conformably overlain by the Guozigou Fm. The upper boundary is marked by the appearance of thin-bedded limestone at the base of overlying Guozigou Fm.
Regional extent
The Kensay Formation is exposed in the west of Middle Tianshan-Beishan Region, distributed at Guozigou of Houcheng County, at Kokirqin (Keguqin) and Ahechat (Akqat) of Jinghe County, and in the area of Mengjikur River. The Kensay Formation varies from 21 to 68 m in thickness.
GeoJSON
Fossils
The Kensay Formation is well fossiliferous, embracing five trilobite zones, from bottom up: (1) Xystridura Zone with Galahetes, Jinghediscus, Keguqinia, Kootenia, Pagetia, Xystridura, and Yukonides; (2) Goniagnostus nathorsti-Ptychagnostus punctuosus Zone with Amphoton, Baltagnostus, Cotalagnostus, Cyclolorenzella, Diplagnostus, Doryagnostus, Elrathia, Goniagnostus, Huochengella, Huzhwia, Hypagnostus, Iniospheniscus, Kootenia, Lisaniella, Myrmecomimus, Nepea, Oedorhachis, Onymagnostus, Pagetia, Palella, Peromopsis, Protohedina, Pseudoperonopsis, Ptychagnostus, Rhodotypiscus, Sunia, and Teratokoputura; (3) Lejopyge laevigata-Centropleura Zone with Centropleura, Lejopyge, Phalacroma, and Yakutiana; (4) Agnostascus orientalis Zone with Aistagnostus, Clavagnostus, Connagnostaus, Homagnostus, Idolagnostus, and Schmalenseeia; (5) Glyptagnostaus stolidotus-G. reticulatus Zone with Aspidagnostus, Corynexochus, Glyptagnostaus, Innitagnostus, Jegorowia?, Onchonotellus, Peratagnostus, Pianaspis?, Proceratopyge and Pseudagnostus.
Age
Depositional setting
Additional Information