Yingebulak Gr
Type Locality and Naming
The reference section is situated in the An’nanbar area in the eastern part of Xinjiang. It was named by Gao Zhisheng et al. in 1960, and was cited officially by the Compiling Group for the Regional Stratigraphic Chart of the Xinjiang Uygur Autonomous Region (1981). Zhong Jian et al. (1991) made a detailed elucidation of the lithostratigraphy and biostratigraphic sequence of the formation.
Lithology and Thickness
Clastics and Limestone. Representing a suite of alternating deposits of carbonate and clastic rocks, and containing coal beds. It is divisible into four members: The lower part of the First member is composed of dark-grey quartz-sandstone, massive in association with fine-grained and coarse-grained quartz-sandstones, intercalated with carbonaceous shale, thin coal layers and coal seams; the middle part of the first member is composed of grey-black carbonaceous siltstone, intercalated with thick-bedded fine-crystalline dolomite, shelly limestone and coal seams; and the upper part of the First member represents interbeds of grey thin- and thick-bedded medium- and fine-grained quartz-sandstones, grey-black carbonaceous siltstone and siltstone; with a thickness of 102 m.
Second member is composed of limestone, sandy conglomerate, clayey shale and coal layers, and is subdivisible into three submembers, with the first submember being complicated in lithology and consisting of sectional interbeds of grey to dark-grey thin-bedded to massive micrites, black-grey carbonaceous siltstone and carbonaceous and clayey siltstones, intercalated often with coal layers of varying thickness; with a total thickness of over 166 m; with the middle and upper parts of the second submember consisting in descending order of light-grey to grey-green medium-bedded siltstones, dark-grey to black-grey carbonaceous shales and silty siltstones, and with the lower part of the second submember consisting of grey, massive boulder-rich quartzite and coarse conglomerate, intercalated with a small amount of coarse-grained sandstone, carbonaceous shale and coal seams in its lower part, yielding plant fossils (phytolites) such as Lepidodendron, Syriangodendron, Neuropteris, etc. in its upper part, with a thickness of 296 m; and with the third submember consisting of interbeds mainly of grey and dark-grey medium-, and thick-bedded, locally massive, micritic fusulinid bio-limestones, calcareous and siliceous dolomites, parts of lithoclastic limestone, spinal limestone, marl and carbonaceous siltstone, intercalated with thin coal layers at its base. The Second member has a total thickness of 126 m.
Third member represents unequal thickness interbeds of grey-green medium-, and thick-bedded silty and fine-grained clayey quartz-sandstones, clayey siltstones, medium-, and thick-bedded clayey pebbled coarse-grained sandstones, coarse-grained clayey quartz-sandstones, pebbled unequigranular quartz-sandstones, intercalated with silty siltstone, with a thickness of 92 m.
The lower part of the Fourth member representing interbeds of light-grey and grey sandstones, siltstones and sandy siltstones, intercalated with dark-grey medium-bedded micrite; and with the middle and upper parts of the Fourth member consisting of purplish red and dark-purplish red massive silty siltstones, intercalated with many layers of medium-grained lithoclastic sandstones, fine-grained lithoclastic sandstones and fine-grained sandstone lenses, with its. The Fourth member has a thickness of 210 m. The entire formation has a visible thickness of 403-990 m.
Relationships and Distribution
Lower contact
The lower part is in a fault contact with the Jixianian System of the Proterozoic Era at different stratigraphic horizons, or is overlapping the latter.
Upper contact
The upper part has been cut by fault and is short of its top part because of its occurrence inside a synclinal axis.
Regional extent
Distributed in a sphere of about 200 km extending from the Annan Dam to the Suorkuli area, and is getting thinner from east to west; with the first member being found only in the area of the Annan Dam on its eastern flank; the second member occurs in the Suishishan area on its western flank, with a thickness of 104-61 m; and the third member of the particular group is changing in its thickness from being of 92 m in the area of the Annan Dam to being of 266 m in the Suishishan area.
GeoJSON
Fossils
The First member yields Fusulinids represented by Ozawainella pseudotingi, Triticites sp.; conodonts such as Streptognathodus elegantulus, S. alekseevi and a great amount of spore-pollens, among which the trilete spore makes up 70%, the monolete spore makes up 24%, and the pollen makes up 6%.
The Second member yields Fusulinids represented by Pseudofusulina, Quasifusulina, Eoparafusulina, Zellia; corals such as Lophophyllum, Artheria; brachiopods such as Dictyoclostus taiyuanfuensis, D. geuenewalati; conodonts such as Streptognathodus wabaunsensis, S. elongatus, S. barskovi, etc.
The Third member yields Fusulinids represented by Eoparafusulina subashiensis, etc.
The Fourth member yields spore-pollen fossils such as Vitreisporites sp., Vittatina sp., Protohaploxypinus sp., Platysaccus sp., Punctatisporites sp., Lycospora sp., etc.,
Age
Depositional setting
Additional Information