Lushuihe Fm
Type Locality and Naming
The type section is located on the south bank of the Lushui River (Lushui He) in Chengguan, Puqi, Hubei. It was named by Zhang Renjie and others in 1982. The Lushuihe Fm originally refers to the Middle Triassic limestone, sand and mudstone strata between the Lower Triassic Xiaohe Fm and the Upper Triassic Puqi Fm, which is located in the southeast of Hubei. In 1992, Wang Zunzhou and others restricted the Lushuihe Fm to the Lower Member (Limestone Member) of the original Lushuihe Fm, and assigned the Upper Member (Sandstone and Mudstone Member) to the overlying Puqi Fm. This lexicon follows the latter one.
Synonym:
Lithology and Thickness
It is mainly dominated by the gray medium-thick limestone with thin argillaceous limestone. Its thickness is 20 to 134 m and the thickest one can be up to more than 200 m. In the middle and lower reaches of the Yangtze River, this formation contains gypsum-salt-bearing layers.
Relationships and Distribution
Lower contact
Its bottom is characterized by the limestone, which is conformable in contact to the underlying Lower Triassic Xiaohe Fm of the gypsum-bearing pseudo-crystalline dolomite.
Upper contact
Its top with limestone is also conformable in contact to the overlying Puqi Fm with purplish red sandstone and mudstone.
Regional extent
This formation is mainly distributed in the southeast of Hubei and the east of Sichuan.
GeoJSON
Fossils
Bivalves: Asoellaillyrica crassistriata, A. subillyrica, Entolium discites, Lima convexa
Age
Depositional setting
It is interpreted as a shallow sea shelf deposit.
Additional Information