Home Multi-Country Search About Admin Login
Cenozoic
Cretaceous
Jurassic
Triassic
Permian
Carboniferous
Devonian
Silurian
Ordovician
Cambrian
Neoproterozoic
Mesoproterozoic

Search by
Select Region(s) to search
Hold Ctrl (Windows/Linux) or Command (Mac) to select multiple
Jiangzhen Formation
Click to display on map of the Ancient World at:
Jiangzhen Fm base reconstruction

Jiangzhen Fm

Period: 
Cretaceous

Age Interval: 
Early Cretaceous, K1jz, (29c)


Province: 
Anhui

Type Locality and Naming

Huaning Basin; south Anhui. The name of Jiangzhen Formation was given by the 311 Regional Metallurgy Geological Team of Anhui in 1970. The type locality is Jiangjiazui (Jiangzhen Township), Huaining County, Anhui. The key section is the Jiangzhen – Shijiafan section in Huaining.

Synonym: （江镇组）, In this same Huaining County, there were younger volcanics of the Wanggongmaio Fm and older volcanics of the Pengjiakou Fm associated with the Jiangzhen Fm in the previous "red Chinese lexicon" (Jurassic column); but these may have been merged into other formations after new dating showed the Jiangzhen Fm is mid-Early Cretaceous?


Lithology and Thickness

This formation is a group of grayish white, light green and light grey rhyolite and rhyolitic breccias. Lower part is composed of light-grey and grey-violet olivine trachytic basalt, trachyte, amygdaloidal pyroxene basaltic trachyte, intercalated with volcanic breccia and tuff, with a thickness of about 612 m. Upper part is mainly of light violet-grey and grey-white potassium-feldspar rhyolite and pyromeride, intercalated with rhyolitic volcanic breccia, with a thickness of about 104 m.


Lithology Pattern: 
Lava


Relationships and Distribution

Lower contact

It conformably contacts with the underlying Gushan Fm (according to that entry)

Upper contact

Regional extent

The formation is distributed in the Huaining, Jiangzhen and Taihu Lake areas. It is distributed essentially in the areas of Jiangjiazui (Jiangzhen Township) and the Xiangming Mt of Huaining County, with a changeable lithology, especially on both the east and west sides of the Wanhe River the difference in lithology of the rocks is so significant that they are difficultly to be correlated. For instance, in the area of Sunjiawu Village at the Xiangming Mt the rock types there are represented chiefly by trachyte, trachytic basalt, basaltic trachyte and potassium-feldspar rhyolite, with a thickness of 103-716 m. As for the area on the eastern side of the Wanhe River the rock types there are such as are mentioned in the description of the naming section. It is 103 to 716 m thick in the Huaining area, 32 to 612 m in the Jiangzhen area.


GeoJSON

{"type":"Feature","geometry":{"type":"MultiPolygon","coordinates":[[[[117.47,31.15],[117.57,31.16],[117.63,31.11],[117.68,31],[117.64,30.95],[117.58,30.89],[117.48,30.82],[117.37,30.73],[117.16,30.62],[117.04,30.58],[117.01,30.62],[117.05,30.66],[117.09,30.71],[117.14,30.8],[117.23,30.89],[117.36,31.07],[117.47,31.15]]]]}}

Fossils

No fossils have been found.


Age 

It is very difficult to confirm the age of this formation, as there is no fossil record. Schematic strat column in the previous "red Chinese Lexicon" had implied that the Jiangzhen Fm spanned the early Tithonian. However, radiometric dates of ca. 128 Ma => mid-Late Hauterivian (Guangfu Xing, Jianqing Li, Zheng Duan, Mingxuan Cao, Minggang Yu, Pingli Chu, Rong Chen. Mesozoic–Cenozoic Volcanic Cycle and Volcanic Reservoirs in East China. Journal of Earth Science, 2021, 32(4): 742-765. doi: 10.1007/s12583-021-1476-1). Zhou Taofa et al. (2008, Geochronology of the volcanic rocks in the Lu-Zong basin and its significance. Sci. China Ser. D-Earth Sci. 51, 1470–1482 (2008). https://doi.org/10.1007/s11430-008-0111-7) had also concluded from SHRIMP (LA-ICP MS) U-Pb dating that :"There were no Jurassic volcanic activities in all the volcanic basins including the Lu-Zong basin in the middle and lower reaches of the Yangtze River area."

Age Span: 

    Beginning stage: 
Hauterivian

    Fraction up in beginning stage: 
0.7

    Beginning date (Ma): 
128.33

    Ending stage: 
Hauterivian

    Fraction up in the ending stage: 
1.0

    Ending date (Ma):  
126.50

Depositional setting

The formation belongs to accumulation of volcanic-eruption facies


Depositional pattern:  


Additional Information


Compiler:  

Wan Xiaoqiao; with additional details from Jingeng Sha (coordinator for Jurassic lexicon)