Luoling Fm
Type Locality and Naming
It was named by the No. 4 Team of the Regional Survey Party of Anhui Province. The naming section is located in between the Yangting area of Huaining County and the Luoling Ridge of Tongcheng County, Anhui Province.
Synonym: （罗岭组）
Lithology and Thickness
Lower member is composed mainly of purple, grey-violet, yellow-green and dark-yellow feldspar-quartz sandstones, feldspar-sandstones, siltstones and silty shales, with its basal part consisting of grey-white pebble-bearing gritstones or conglomerates, with a thickness of about 1017 m. Upper part is purple, dark-grey, grey-green feldspar-quartz sandstones, calcareous siltstones, silty shales, intercalated locally with conglomerates and marls, with a thickness of about 1151 m.
Relationships and Distribution
Lower contact
Its basal part is in a disconformable contact with the underlying Moshan Fm
Upper contact
Regionally (in Huaining county), the next younger unit are the mid-Early Cretaceous volcanics of the Shuangmiao Fm
Regional extent
It is distributed essentially in the Huaining, Lujiang-Zhengyang and Ma’anshan regions. The lithology and thickness of the formation are changeable slightly in various regions. As in the area of the Luoling Ridge easterly till the Laozhuang Village and Hengbu area of Zhongyang County the rock grains are getting finer, the amount of yellow-green concretion-bearing marl intercalations are increasing, and the thickness is getting smaller, being of about 665 m, yielding abundant bivalve fossils. Still easterly till the area of the Hengshan Mt of Chuxian County the lower member of the formation represents an alternating layer of a set of purple and grey-white feldspar-quartz sandstones in association with muscovite-bearing argillaceous siltstone and coarse-grained feldspar-quartz sandstone, with a thickness of about 507 m, while its upper member is composed mainly of variegated pebble-bearing medium-grained sandstones, calcareous siltstones and silty mudstones, intercalated with tuffaceous conglomerates, marls, locally with quartz-trachyandesites, with a thickness of 618 m. In the vicinity of the Pengzhuang Village the thickness of the formation is over 475 m, and in general there is a tendency of a gradual thickening from west to east.
GeoJSON
Fossils
It yields bivalves as represented by the Lamprotula (Eolamprotula) cremeri-Pseudocardinia kweichouensis assemblage; Gastropods whose major members are Biomphalaria depressa, B. altaica, Amnicola cf. zhejiangensis, Aphanotylus sp., Bithynia sp., and etc.; Spinicaudata such as “Nestoria” cf. pissovi, N. spp.; Ostracods as represented by Darwinula impudica, D. changxinensis, D. cf. oblanga; insects fossils such as Samaroblatta turanica, Mesoblattina sp.; and plant fossils as represented by Onychiopsis cf. elongata, Coniopteris sp., cladophlebis sp. and Elatocladus sp.
Age
Depositional setting
The formation belongs to fluvial-lacustrine deposits.
Additional Information