Karamay Fm
Type Locality and Naming
Fan Chenglong named it in 1956. The named section is located in Karamay, Xinjiang. The reference section is located at the bottom of the Karamay Deep Gully, Xinjiang. Lower formation in the Xiaoquangou Gr.
Synonym: Kelamayi Fm, Karamayi Fm [Note: Used Karamay Fm in this Lexicon, because all other Lexicon entries and most papers (e.g., Tong et al., 2019, Triassic integrated stratigraphy and timescale in China) have that spelling.], Baiyanghe Formation. In 1956, Fan Chenglong named it the Lower Kelamayi Series and the Upper Kelamayi Series. In 1964, Xinjiang Petroleum Bureau renamed it the Kelamayi Group and subdivided it into the upper, middle and lower subgroups. From 1977 to 1981, the compiling group of regional stratigraphic tables in Xinjiang Uygur Autonomous Region renamed the Zhongya Formation as the Karamay Formation, and the age was the Middle and Late Triassic.
Lithology and Thickness
The main lithology is gray, gray green, yellow sandstone, mudstone and conglomerate. Lower part is interbedded with gray-green, gray-green sandy mudstone, gray-green and brownish red sandstone, interbedded with gray-green conglomerate and gravel sandstone. Upper part is interbedded with gray-green sandstone, gravel sandstone, conglomerate, gray-green, dark gray and a small amount of brownish red mudstone. The thickness is 69.1 m.
Relationships and Distribution
Lower contact
The yellow-green and grey-green conglomerate at the bottom of Jimusar to Urumqi is conformable contact with the underlying lower Triassic Shaofangou Fm. In the north Junggar Basin, the underlying unit is the Jianshangou Fm of lower Triassic.
Upper contact
The top of the underlying Karamay Fm (Kelamayi Fm).is in comformable contact with the overlying light-yellow mudstone at the bottom of the overlying Huangshanjie Fm.
Regional extent
From Jimsar County to Fukang area in Junggar Basin, the sediments are relatively thick (507.1~566.5 m). In the Turpan Basin, there are lacustrine deposits with a thickness of 265~375 m from Taoshuyuan to Tuoxun. In the Tarim Basin, it is mainly distributed from Kuqa to Baicheng area, with a thick thickness in the east (572 m in the Kuqa River) and a thin thickness in the west (359.82 m in the Kapushaliang River).
GeoJSON
Fossils
Arthropods (Karamay Deep Bottom Gully): Almatium elongatum, A. guseui; Almatium elongatum, A. guseui; Bivalves: Ferganoconcha sibirica, F. rotunda, F. cf. minor, Sibiriconcha anodontites; Conchostracans: Mesolimnadiopsis karamaica, M. spp., Lioestheria euenkiensis; Plants: Danaeopsis fecunda, Neocalamites hoerensis, N. spp., Chiropteris(?) yuani, Glossophyllum? shensiense, Thinnfeldia nordenskioldi, Todites cf. shensiensis, Sphenobaiera cf. crassinervis, Bernouillia zeilleri; Vertebrates (Fukang Region): Parakannemeyeria brevirostris, Parotosaurus sp.; Microspores (Jimusaer region): Apiculatisporites-Punctatisporites-Aratrisporites- Colpectopollis assemblage zone; Megaspores: Tuberculatisporites humilispinosus-Dijkstraisporites beutleri- Maexisporites magnuszewensis-Trileites (Calamospora) assemblage zone
Age
Depositional setting
This formation is lacustrine and fluvial facies.
Additional Information