Mushirabuka Gr
Type Locality and Naming
The type section is located on the southwest side of Mushirabuka, 170 km northeast of Gê’gyai County, Tibet. It was named by the Regional Geological Survey Party of Tibetan Bureau of Geology in 1987.
Lithology and Thickness
Pebbly Claystone and Sandstone, Volcaniclastics and Limestone. Lower part comprises a suite of slightly metamorphosed gray-green and gray-black thin- to moderately thick-bedded pebbly slate, pebbly sandstone, platy siltstone, siltstone (with ripple marks and diagonal bedding), sandstone, as well as volcanic brecciated tuff and gray acid tuff, thickness >1047.3 m. Upper part consists of gray-black, gray-white and purple-gray bioclastic limestone, sandy limestone and crystalline limestone, rich in fossils, with thickness >148.7 m. Thickness generally 2000−5000 m.
Relationships and Distribution
Lower contact
Unknown: The bottom is not exposed at type section.
Upper contact
Conformable contact with the overlying Lower Permian Cainaha Fm (= Tunlonggongba Fm of Kungurian age) at the type section.
Regional extent
Exposed in the areas such as Kongkala Mt. and Doima of Rutog County, Mushirabuka of Gê’gyai County, as well as Gangmaco and Tuohepingco of Chabug District of Gerze County.
GeoJSON
Fossils
Lower part has Ammonoids Agathiceras sp., Metalegoceras sp., Pseudofusulina sp. and Schwagerina sp.; Brachiopod Terebratuloidea cf. beta and trilobite Phacopidae. Upper part includes Brachiopods Stepanoviella sp., Stenoscisma cf. amoenus, Notothyris cf. mapingensis, Dictyoclostus tenuireticulatus, Dielasma juresanense minor, Neoplicatifera lipoensis, Plicochonetes cf. chaoi and Punctospirifer sp., and Coral Lonsdaleiastraea sp.
Age
Depositional setting
It is interpreted as a deltaic (Lower part; but "pebbly slate" suggests glacial-marine, similar to coeval Cameng Fm in adjacent region?) and neritic (Upper part)
Additional Information