Wennan Fm

Shandong

Jingeng Sha (coordinator) Commission on the《Regional Stratigraphic Charts of China (Draft)》in 1956. The naming section is located in the Wennan region of Xintai City, Shandong Province, with its reference section being situated to the south of the Fenshuiling Village, Xintai City.

Synonym: （汶南组）

Lithology and Thickness:

It is composed mainly of purple conglomerate, sandy conglomerate and sandstone, intercalated with grey-green siltstone and grey-black shale, with a thickness varying in a range from over a hundred meters to 400 m.

Lithology-pattern: Aus conglomerate

Relationships and Distribution:

Lower contact:

Its basal part is in an unconformable contact with the underlying Paleozoic Erathem.

Upper contact:

Regionally, the schematic strat column indicates the next younger unit as Fangzi Fm. In 1989, Liu Dezheng placed the stratigraphic position of the Wennan Formation above the Fangzi Fm. However, owing to the fact that the direct contact relations between the two formations have not been seen anywhere in one and the same section, in this lexicon the Wennan Fm has been placed below the Fangzi Fm for the time being just on the basis of the younger-and-older relationship between the two formations as indicated by the biotic fossils yielded there.

Regional extent:

It is distributed largely in some faulted basins of central Shandong, including the Yiyuan, Laiwu, Xintai-Mongyin and Pingyi Basins. In the Fenshui section of Xintai City the formation yields “conchostracan” and spore-pollen fossils, and with a thickness of only 123 m; of about 128 m in the area of the Erlang Mts of the Hebeizhuang Village to the Guanzhuang Village of the Wujia region, Yiyuan County; and a visible thickness of the formation in the drilling wells being of 159 m in the Tianchen area of Tengzhou City.

GeoJSON:

Fossils:

It yields “conchostracan” fossils such as Palaeolimnadia baitainbaensis, P. longmenshanensis, P. chuanbeiensis, Euestheria taniiformis, E. aff. shandanensis and E. shandongensis; and spore-pollen fossils predominated by Classopollis spp.

Age:

Schematic strat column in the previous "red Chinese Lexicon" had implied that the Wennan Fm spanned Toarcian.

Age span:

Beginning stage: Toarcian

Fraction up in beginning stage: 0.0

Beginning date (Ma):

Ending stage: Toarcian

Fraction up in ending stage: 1.0

Ending date (Ma):

Depositional setting:

The formation belongs to fluvio-lacustrine-facies deposits.

Depositional-pattern:

Additional Information

Compiler

Jingeng Sha (coordinator)