Lushanxian Fm
Type Locality and Naming
The naming locality is the Miaoxi Tea Farm to Yaquekou, Xinhua Township, 75 km northwest of Lushan County, Sichuan. Named by Wang Zhi and Lin Yuancan in 1975.
Synonym: originally called Lushan Fm
Lithology and Thickness
Primarily brownish red and brown mudstone and orange-red siltstone, occasionally with thin marlstone beds. Lower part is mainly siltstone with minor medium- to coarse-grained, lithic sandstone and limestone gravels, showing fine bedding. Middle and Upper parts are dominated by mudstone, occasionally intercalated with muddy siltstone and grayish green, small spots or small gypsum lenses. The age is Eocene–Oligocene and the thickness is 550 m.
The formation is thick in the west and thin in the east, being 687 m thick at Shiyang, Tianquan, 623 m thick at Luojiaba, Tianquan, 416 m thick at Dashibangou, Lushan, 311 m thick at Guanhua, Ya’an, 112 m thick at Baizhimiao, Ya’an, 205 m thick west of the seat of Mingshan County, and only 5 m at Yuguanpo, Mingshan County.
Relationships and Distribution
Lower contact
Its base is marked by 6 m thick alternating beds of brownish red, medium-bedded, muddy siltstone and silty mudstone, which has a conformable contact with the mudstone at the top of the underlying Paleocene–Eocene Mingshan Fm.
Upper contact
It is overlain with slightly angular unconformity by the Neogene (Liangshuijian Fm) or covered by the Quaternary.
Regional extent
The strata are distributed in a NE-trending zone on both limbs of the Lushan syncline.
GeoJSON
Fossils
This formation yields fishes, gastropods, ostracods and charophytes.
Age
Depositional setting
Additional Information