Daan Fm
Type Locality and Naming
Songliao Basin. The type section is well ZK103 section located at the Laifu Village in Da’an County, Jilin Province. It was named by the Songliao Petroleum Exploration Bureau in 1960 (unpublished) and introduced by Jilin Bureau of Geology and Mineral Resources in 1988. Geographical coordinates of the type section: 45°34′00″N—123°00′00″E (GPS).
Synonym: Da'an Fm
Lithology and Thickness
It is characterized by the greyish-green, yellowish-green, greyish-white and grey sandstones, conglomerates, and mudstones. The rocks are coarse-grained in the lower part and fine-grained in the upper part and show a pronounced rhythm. The thickness is 82 m in the type section and varies from 48 m to 126 m in the district.
Relationships and Distribution
Lower contact
The Da’an Fm is in conformable contact with the underlying Yi’an Fm (Yian Fm) or in faulted contact with the underlying Mingshui Fm.
Upper contact
It is in faulted contact with the overlying Taikang Fm [Not in English Lexicon entries].
Regional extent
The Da’an formation is distributed in the Songnen Plain in Jilin and Heilongjiang Province.
GeoJSON
Fossils
Ostracodes (including Ilyocypris and Candona), Sporopollen assemblages (Caryapollenites simplex- Momipites coryloides- Celtispollenites sp.- Tsugaepollenites igniculus), and plants (including Castanea miomollissim) are found in this formation.
Age
Depositional setting
Fluvio-lacustrine deposits.
Additional Information