Lawula Fm
Type Locality and Naming
The holostratotype located in Lawula County, Mangkang County, Xizang Autonomous Region (Tibet), which was remeasured by the Third Regional Geological Survey Team of Sichuan Province in 1974. Pu Li named the Lawula layer in 1959. The Third Regional Geological Survey Brigade of Sichuan Province renamed it the Lawula formation in 1974.
Synonym: The Lawula Formation was also called Lawula Andesite.
Lithology and Thickness
The Lawula Formation consists of purplish-red, grayish-white and yellowish-green glutenite, mudstone, siltstone and sandstone witch partly contain tuff and interbeded with thin coal seam and coal line. Middle part is intermediate-acid, alkaline trachyte, trachyandesite, biotite quartz rhyolite, interbedded with variegated glutenite. The thickness of exposure ranges from 59 m to 1700 m.
Relationships and Distribution
Lower contact
The Lawula Formation unconformably overlies the Cretaceous Xiangdui Gr (Cret. Column 6c; Markam); but older China Lexicon Strat chart confusingly schematically indicatesd next older regional unit as the Dingqing Fm (Paleogene). See "Age" below.
Upper contact
The upper boundary is unobservable.
Regional extent
Basu County and Mangkang County, Tibet Autonomous Region.
GeoJSON
Fossils
The Lawula Formation contains abundant plant fossils, pollen, charales, gastropods and ostracods. Members of the Palaeoecology Group, Xishuangbanna Tropical Botanical Garden collected four distinct plant-fossil assemblages (MK1–4) witch notably different in composition from this formation.
Age
Depositional setting
Lacustrine and delta facies.
Additional Information
Tao Deng, Sukuan Hou, J.Z. Qigao, Q. Li, Q.Q. Shi, B.Y. Sun, S.Q. Wang, F.X. Wu