Hurleg Fm

The type section is located near the Huaitoutala Coal Mine, Delingha, Qinghai. It was named by Mu Enzhi et al. in 1963.

Synonym: Keluke Fm (translation as given on Carboniferous strat column chart)

Siltstone, Limestone and Sandstone. Lower subformation is composed of gray and gray-black siltstone, silty shale, carbonaceous shale, marl and organic limestone, intercalated with cone-in-cone limestone and thin coal seams, with pebbled grit and quartzose sandstone at bottom, 79.2 m thick. The upper member of the Lower subformation consists of gray moderately thick to thick-bedded clayey organic limestone and silty shale, intercalated with organic limestone, bioclastic limestone and fine-grained sandstone, and locally with siderite nodule layers, thin coal seams or coal streaks, 185.6−394 m thick. Upper subformation is characterized by development of rhythmic layers of gray-white to gray quartzose sandstone, shale and limestone, 296.1−515.3 m thick.

Around Zhabusagaxiu in the eastern part, it comprises gray-yellow, gray-white and gray-green sandstones, gray shale and carbonaceous shale, intercalated with coal streaks or coal seams and limestone, thickness >212−295 m.

The Lower subformation biota is dominated by Plants, namely Rhodea chinghaiense, etc., plant Rhodeopteridium chinghaiense-Lepidodendron aolungpylukense assemblage, brachiopod Choristites, etc. There are two Fusulinid zones, the Pseudostaffella sphaeroides and Pseudowedekindellina prolixa zones ascending. Brachiopods are especially well developed, containing almost all genera and species of the Yanghugou Fm at Qingyuan, Gansu.

The Upper subformation biota is dominated by Fusulinids, followed by brachiopods and corals, with minor cephalopods and bryozoans. The Fusulinids comprise the ascending Fusulina-Fusulinella and Profusulinella-Pseudostaffella qinghaiensis assemblage zones.

It is interpreted as marine-continental deposits