Shangshihezi Fm
Type Locality and Naming
The type section is located at the Shihezi Trench in the Chenjia Valley of the East Hills of Taiyuan City, Shanxi Province. It was named by Norin E., in 1922.
Synonym: Upper Shihhotse Fm
Lithology and Thickness
Clastics. In the naming locality area the formation represents a suite of variegated sandstone, siltstone and cherty layer, intercalated with a small amount of thin coal layers and marls. It comprises three lithological members: First member is composed mainly of grey-yellow and yellow-green strata, representing iron-manganese-bearing rocks, and is commonly possessed of 5 sedimentary rhythms. Second member is composed chiefly of yellow-green feldspar-greywacke and quartz-greywacke, intercalated with variegated sandy siltstone, shale and aluminous shale, constituting 5 sedimentary rhythms, with its basal sandstone representing thick-bedded pebbled sandstone. Third member is composed of more variegated, purple or blue-purple siltstone, sandstone and cherty layers, and is possessed of about 6 sedimentary rhythms. In the Datong Coal Mine in the northern part of Shanxi Province the sandstones in the formation represent in most cases pebbled grey-white greywacke and feldspar-rich sandstone.
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Relationships and Distribution
Lower contact
Conformable contact with the underlying Shihezi Fm, but locally being in a disconformable contact with it.
Upper contact
Conformable contact with the overlying Sunjiagou Fm sandstone.
Regional extent
Toward and into the Ningwu-Jingle Basin in the southern part of the province the granularity of the rocks is getting smaller, and up to the Taiyuan, Jiaocheng areas and the southwestern part of Shanxi Province the manganese-iron-bearing strata and cherty layers are getting more and more developed. In the Yangquan area of Shanxi Province, Fengfeng area of Hebei Province, Xinwen area of Shandong Province, Yuzhou and Shuicheng areas of Henan Province, and Huainan area of Anhui Province the formation is intercalated with sponge-spicule-bearing siliceous rocks. In the area of Benxi City, Liaoning Province the formation is composed of interbeds of grey and yellow-green siltstone and siltstone, intercalated with pebbled sandstone, with a thickness of 1110 m. In the area of Tangshan City, Hebei Province it used to be known as the Guye Fm, and is composed of yellow-green and purple sandstone, siltstone and siltstone, with a thickness of 397 m; in the Hancheng area of Shaanxi Province it is composed of interbeds of purple and yellow-green siltstones and siltstones, intercalated with pebbled sandstone, with a thickness of 261-277 m; in the Yuzhou and Pingdingshan areas of Henan Province it is composed of interbeds of yellow-green sandy shale, sandstone and patch shale, containing six, seven and eight coal measures, locally nine coal measures, with a thickness of 252-300 m; in the Zibuo area of Shandong Province it is composed of yellow-green sandstone and siltstone, intercalated with purple siltstone and sandy conglomerate, with its base consisting of grey-colored allite, with a thickness of 525 m; in the Zhengji, Panjia’an and Fengpei areas of Xuzhou City, Jiangsu Province it is composed of variegated shale, sandy shale and sandstone, with a thickness of 250-560 m; in the Huainan and Guaibei areas of Anhui Province, the formation is composed of grey siltstone, sandstone and siltstone, intercalated with purple patch siltstone, with a thickness of 566-700 m; meanwhile in the Huaibei area it contains 1-6 layers of coal, and 25 layers of coal in the Huainan area, among which there occur more stable mineable coal layers. In the Hulusitai area of Helan Mt. the formation is composed of yellow-green sandstone, intercalated with thin-bedded shale and claystone bands, with a thickness of 382 m, containing many layers of brick-red tuffs. The Shanshihezi Fm in the Huainan area contains stable coal seams suitable for mining. As for the Pingdingshan Mt. area, where although many coal-bearing layers occur, nearly no mineable coal seams were formed.
GeoJSON
Fossils
Abundant plant fossils (phytolites), which have been incorporated into the Neuropteridium coreanicum-Lobatannularia ensifolia-Chiropteris reniformis-Pecopteris lativenosa assemblage. The marine animal fossils in the Shangshihezi Fm are rare. In the Yuzhou and Yongcheng areas of Henan Province, the Xuzhou area of Jiangsu Province, the Huainan and Huaibei areas of Anhui Province it yields Brachiopods represented by Lingula sp.; Bivalves represented by Wilkingia sp., Palaeanodonta cf. fischeri, Naiadites sp., Carbonicola sp., etc. In addition, in the Xuzhou area of Jiangsu Province, the Yongcheng and Pingdingshan areas of Hebei Province, the Huainan area of Anhui Province it yields the Paracuneatochara-Gemmichara assemblage of Chareae.
Age
Depositional setting
It is interpreted as terrigenous clastic deposits formed during the marine regression on the North China Landmass, but from north to south and from west to east, there occurred gradual changes from continental facies and paralic transitional facies into the gulf-facies and lagoon-facies in Huainan area of Anhui Province and the southwestern part of Henan Province. With the southerly shifting of the coastline there were formed some locally mineable coal seams, as well as stable mineable coal seams in the coal-forming swamp-environment developed on a constructional delta.
Additional Information