Hepingxiang Fm

Yunnan

Jingeng Sha (coordinator) Group for the Regional Stratigraphic Chart of Yunnan Province, 1978), and was first cited publicly by the Nanjing Institute of Geology and Palaeontology, Academia Sinica and others in 1975. The reference section is situated in the area of Huakaizuo of Yangbi County, Yunnan Province. It was named by the No. 16 Geological Party under the Geological Bureau of Yunnan Province in 1968.

Synonym: （和平乡组）

Lithology and Thickness:

It is composed essentially of alternating layers of yellow, yellow-green, purple and grey-violet mudstones and calcareous mudstones together with yellow-green and purple siltstones and fine-grained sandstones, intercalated with marls and bioclastic limestones. It is with a thickness of 613 m.

Lithology-pattern: Shallow-marine marl

Relationships and Distribution:

Lower contact:

Its basal part with a 24.2 m thick layer of yellow-green massive coarse-grained sandstone is in a conformable contact with the underlying Huakaizuo Fm

Upper contact:

It is in an unconformable contact with the overlying Bazhulu Fm

Regional extent:

The formation is distributed in the Lanping-Simao area, with a similar lithology in various regions. In the eastern part of its distribution region the marine deposits are less than those in the western part of the region. It is overlain conformably by the Bazhulu Formation of the upper Jurassic. Meanwhile, the marine deposits are more intensively developed in the western part of its distribution region. In the areas of Mojiang and Luchun it contains gypsum and salt locally. Its total thickness varies commonly from 200 m to 800 m, and is getting greater in the areas of Jinggu, Jinghong and Menghai, being of 2400-3600 m.

GeoJSON:

Fossils:

It yields abundant various kinds of fossils, of which there are found bivalves as represented by Protocardia stricklandi, Thracia extensa, Quenstedtia quadrata, Isognomon latoconvexa minor, and Liostrea birmanica; Ostracods, by Aglaiocypris subelliptica, Schuleridea triebeli; Gastropods, by Vanikoropsis minuta; continental bivalves, by Psilunio thailandi, P. ovalis, Lamprotula (Eolamprotula) guangyuanensis, cuneopsis sichuanensis and etc.; Ostracods, by Darwinula lufengensis, D. impudica, Metacypris monosulcata, as well as charophyte fossils. In the northern part of its distribution region it yields ammonites fossils as well.

Age:

Schematic strat column in previous "red Chinese Lexicon" had implied that the Hepingxiang Fm spanned the late-Middle Jurassic.

Age span:

Beginning stage: Bathonian

Fraction up in beginning stage: 0.0

Beginning date (Ma):

Ending stage: Callovian

Fraction up in ending stage: 1.0

Ending date (Ma):

Depositional setting:

Depositional-pattern:

Additional Information

Compiler

Jingeng Sha (coordinator)