Ermaying Fm

The Shanxi Stratigraphy Team of the Chinese Academy of Sciences, Liu Hongyun, was named in 1959. The named profile is located in Nanliang Mountain, Ermaying, Ningwu, Shanxi; the reference profile is located in Xileshi, Heshun County, Shanxi.

Synonym: Zhifang Fm, Zhifang Gr, Zhifeng Fm (see Additional Information)

It is composed of gray-green, yellow-green, gray-white feldspar sandstone and purple-red and dark purple sandy mudstone with a complete sedimentary cycle. It can be divided into two sections: Lower section is gray-green, yellow-green, light gray-green thick layer to medium-thin layer, medium fine-grained feldspar sandstone with gray-green shale, purple-red mudstone, thin sandy mudstone and gray-purple conglomerate lens. Upper section is light gray-green, gray, gray-white, light flesh red thick layer, medium-thick layer of fine-grained feldspar sandstone and purple sandy mudstone interbedded or mudstone interbedded with sandstone.

The upper section is rich in fossils of the "Chinese Kenshi Fauna" Ordosia, Sinokannemeyeria, Parakannemeyeria, Shansiodon, Shansisuchus; plant fossils Todites, Neocalamites, Voltzia, Aipteris wuziwanensis, Pleuromeia wuziwanensis, Nilssonia, Ginkgorisites, Protoblerattispunctum, etc.; Combination still contains leaf limbs fossils.

This group is a semi-dry hot-semi-temperature humid climate inland river facies deposits.

Lithology and Thickness:

It is composed of gray-green, yellow-green, gray-white feldspar sandstone and purple-red and dark purple sandy mudstone with a complete sedimentary cycle. It can be divided into two sections: Lower section is gray-green, yellow-green, light gray-green thick layer to medium-thin layer, medium fine-grained feldspar sandstone with gray-green shale, purple-red mudstone, thin sandy mudstone and gray-purple conglomerate lens. Upper section is light gray-green, gray, gray-white, light flesh red thick layer, medium-thick layer of fine-grained feldspar sandstone and purple sandy mudstone interbedded or mudstone interbedded with sandstone.

Lithology-pattern: Clayey sandstone

Relationships and Distribution:

Lower contact:

At the bottom, a thick layer of gray-green feldspar sandstone is in integrated contact with the underlying Heshanggou Fm, and there are short-term interruptions locally.

Upper contact:

It is in integrated contact with the overlying Tongchuan Fm, 550 m thick.

Regional extent:

Widely distributed in the Ordos Basin and surrounding areas, the lithology is basically stable, but the single layer of sandstone and mudstone changes greatly, and the sandstone and mudstone interchange and change. The bifurcation tip goes out.

GeoJSON:

Fossils:

The upper section is rich in fossils of the "Chinese Kenshi Fauna" Ordosia, Sinokannemeyeria, Parakannemeyeria, Shansiodon, Shansisuchus; plant fossils Todites, Neocalamites, Voltzia, Aipteris wuziwanensis, Pleuromeia wuziwanensis, Nilssonia, Ginkgorisites, Protoblerattispunctum, etc.; Combination still contains leaf limbs fossils.

Age:

Tong et al. (2019; Triassic integrative stratigraphy and timescale of China; Science China: Earth Sciences, 82: 189-222) indicate that it as early through middle Anisian.

Age span:

Beginning stage: Anisian

Fraction up in beginning stage: 0.0

Beginning date (Ma):

Ending stage: Anisian

Fraction up in ending stage: 0.75

Ending date (Ma):

Depositional setting:

This group is a semi-dry hot-semi-temperature humid climate inland river facies deposits.

Depositional-pattern:

Additional Information

The Ermaying Formation referred to at the time of naming represents “the upper part is covered by the Yanchang Series, and the lower part is a layer of gray-yellow mixed red-green medium-grained quartz sandstone and the boundary between Shiqianfeng Series and Shanggou Fm. The upper part contains abundant vertebrate fossils. Groups and plant fossils represent the deposits from the late Early Triassic to the early Middle Triassic". In 1959, Gan Kewen and others formally proposed the establishment of the "Zhifang System". Compared with the "Er Ma Ying System" in Shanxi, it belongs to the Middle and Lower Triassic. Since 1962, the Chinese Academy of Geological Sciences in the eastern Ordos Basin has confirmed that the "Zhifang Group" and the "Ermaying Group" in Shanxi are basically the same set of strata, and both produce "Chinese Ken's Animal Group Fossils"; according to the spine, plant and spore In the study of fossils such as powder, the "Ermaying Group (Tong)" was renamed the "Ermaying Group", the "Zhifang Group" was abandoned, and its age was determined to be the early Middle Triassic.