Tuntianying Fm
Type Locality and Naming
Yanji Basin. Yang Xuelin erected the Tuntianying volcanic rock formation in 1959. The section for the designation is at Nantun of Tuntianying of Sandao township of the Yanji City, Jilin.
Synonym: sometimes merged as the lower part of the Changcai Fm (see that entry)
Lithology and Thickness
The Tuntianying Formation is characterized by dark-purple and greyish-purple conglomerates, acidic lavas and andesitic volcanic breccias, associated with yellowish and grey-black shaly mudstones, silty mudstones and fine-grained sandstones with quartz and feldspar debris, locally with a layer of rhyolites (Tianqiaoling Fm). The volcanic component include andesite, agglomerate, andesitic tuff, tuffaceous sandstone, dacite and tuff. The formation is 1515.3 m thick.
Relationships and Distribution
Lower contact
Its base marked by andesitic agglomerate contacts by fault with the underlying Paleozoic granite, or the metamorphic Tumen Gr.
Upper contact
It top is contacted by the overlying Changcai Fm.
Regional extent
The present formation is mainly distributed in Tuntianying of the Yanji basin, the Mingyue town of the Antu basin, Chengqianglazi, Shajingou, Miaogou and Bahaoguaizi of the Wufeng and Yingou basins. In the Chengqianglazi-Qinhetun area, it is dominated by intermediate and acidic volcanic rocks with a small amount of intermediate lava, ranging from 320 to 520 m in thickness. In the Shajingou area, it is represented by intermediate lava interbedded with intermediate pyroclastic rocks, constituting four eruptive rhythmic beds, with a thickness in excess of 800 m. In the Ciweigou area, it consists of two major intermediate volcanic eruptive cycles, with a thickness of more than 1578 m. In the Antu basin, it is mainly built up by andesitic breccia and andesite, with a thickness of more than 1000 m. As exposed by borehole, the top of the formation lies conformably under the Changcai Fm in the Yanji basin.
Based on rock associations (effusive rocks, lavas and sediments), it can be roughly correlated with the Didao Fm of the JBM areas and the Yixian Fm, Huoshiling Fm and probably the Shahezi Fm (Sha, 2007a).
GeoJSON
Fossils
The sedimentary intervals contain rare plant fossils; with floras Coniopteris cf. burejensis, Acanthopteris gothani, Onychiopsis sp.
Age
Depositional setting
It belongs to volcanic facies.
Additional Information
Enhanced with Igor N. Kosenko, Jingeng Sha and Boris N. Shurygin (2021). Upper Mesozoic stratigraphy of Sikhote-Alin (Russian Far East) and northeastern China: Non-marine and marine correlations. Part 1: Upper Jurassic-Hauterivian AND 2. Barremian-Aptian. Cretaceous Research, 124: articles 104811 (https://doi.org/10.1016/j.cretres.2021.104811) AND 104812 (https://doi.org/10.1016/j.cretres.2021.104812)