Maladun Fm

Songpan region, eastern Tibet Plateau. The holostratotype is the Hongtupo section which locates on the east side of Maladun, Hongtupo Town, 30 km southwest of Songpan County, Sichuan Province. Maladun coal measure was named by the Ganzi Regional Geological Survey Team of Sichuan Geological Bureau in 1959; it was described by the Second Regional Geological Survey Team of Sichuan in 1975. It was measured by the Ganzi Regional Geological Survey Team of Sichuan Geological Bureau in 1959.

Synonym: Gu et al. (1997) of the Stratigraphy Cleaning Group of Sichuan Provincial Bureau of Geology and Mineral Resources believed that this group was a synonym of the Changtai Fm.

The Maladun Formation consists of light yellow or grayish-white thin-layered fine-grained conglomerate, clayey siltstone, claystone and marl, which rhythmically interbedded with multiple layers of inferior lignite. The thickness of the exposure is 186 m.

The Maladun Formation yielded abundant plant fossils, pollen, and gastropods. The flora is mainly Quercus-Cyperacites assemblage. The palynoflora is characterized by rich presence of Ulmaceae, Betulaceae and abundant Pinaceae pollen with rare spores.

Inland lacustrine facies. The conglomerates at the base are interpreted to have been deposited in an alluvial-fluvial channel environment, and the coal with laminated siltstone was produced in a swamp on the alluvial/fluvial fans in a temperate and wet climate.