ammonites

Leidapo ML-45: Anisian, China

Where & when
Geology
Taphonomy & methods
Metadata & references
Geography
Country:China State/province:Guizhou
Coordinates: 26.9° North, 108.7° East (view map)
Paleocoordinates:18.0° North, 96.4° East
Basis of coordinate:based on nearby landmark
Geographic resolution:small collection
Time
Period:Triassic Epoch:Middle Triassic
Stage:Anisian 10 m.y. bin:Triassic 2
Key time interval:Anisian
Age range of interval:245.0 - 237.0 m.y. ago
Stratigraphy
Formation:Qingyan Member:Leidapo
Stratigraphic resolution:group of beds
Stratigraphy comments: The Qingyan Formation is composed of limestones and mudstones and is about 800m thick. In ascending order, it is subdivided into the Xiaoshan, Mafengpo, Yingshangpo, Leidapo, and Yuqing members. According to palaeontological data, the latter two members are assigned to the upper Anisian, whereas the other three are regarded as lower Anisian in age.
Lithology and environment
Primary lithology: mudstone
Includes fossils?Y
Lithology description: The Leidpo Member discussed in this paper, occupying the lower part of the upper Anisian, is about 200m thick and consists of mudstones, shales and marls. this member is characterized by fossiliferous mudstones and marls. It is grouped into three parts. The lower and upper parts are mainly composed of massive. laminated mudstone with abundant "paper shelled bivalves". The middle part consists of alternating beds of mudstone and marl. The Qingyan Formation is present in the northern part of the Middle Triassic Nanpanjiang Basin (or the Dian-Qian-Gui Basin), which was filled mainly with carbonate platform, bank and siliciclastic basinal deposits. the shallow-water carbonate platform is called the Yangtze Platform and was a stable palaeogeographic element from the Late Proterozoic to the Triassic.
Environment:marine indet.
Taphonomy
Size of fossils:macrofossils
Collection methods and comments
Collection methods:field collection
Reason for describing collection:paleoecologic analysis
Metadata
Database number:42377
Authorizer:D. Bottjer Enterer:N. Bonuso
Modifier:N. Bonuso Research group:marine invertebrate
Created:2004-07-28 12:18:16 Last modified:2004-08-21 14:23:21
Access level:the public Released:2004-07-28 12:18:16
Reference information
Primary reference:
11210 T. Komatsu, J. Chen, M. Cao, F. Stiller, and H. Naruse. 2004. Middle Triassic (Anisian) diversified bivavles: depositional environments and bivalve assemblages in the Leidapo Member of the Qingyan Formation, southern China. Palaeogeography, Palaeoclimatology, Palaeoecology 208:207-223 [D. Bottjer/N. Bonuso/N. Bonuso]