Zhenjiang Fm

Changchun Institute of Geology Heilongjiang area survey team in 1960 named. The named section is located at 3-4 sub-field of 851 Farm in the north section of Dumu River Highway, Hulin, Heilongjiang, to Dadonggou, east of Dahe town, Heilongjiang. In 1960, according to the naming section of Heilongjiang area survey team of Changchun Institute of Geology, the Upper Triassic, which is dominated by siliceous rocks and tuff, was named Zhenjiang Fm. In 1979, the Regional Stratigraphic Table Compilation Group of Heilongjiang Province publicly quoted one name of Zhenjiang Fm for the first time, and maintained the original meaning.

Synonym: Wang Xiuzhang (1959) named the Marine Upper Triassic in the Nadan Hadaling area in the eastern Heilongjiang Province as "Qingjiang Group" according to the comprehensive sequence. In 1982, Zhao Jinke et al proposed elevating the Zhenjiang Formation to a group ranking.

It is mainly composed of black siliceous rock, tuff with dark gray basalt and gray limestone. Its thickness is 1500 m. In 1986, Wang Chengyuan et al. took the Chigangshan quarry section of Shengli Ranch, Raohe County, Heilongjiang Province as the named section and named the Shengli Fm. That formation, which is placed here as part of the Zhenjiang Fm, is mainly composed of thin- and medium-bedded gray dense phanocrytic or fine crystalline limestone, which is interbedded with thin siliceous rocks. The thickness is tens of meters, and is rich in conodonts.

Conodonts: (1) Epigondolella bidentate zone; (2) E. postera zone; (3) E. multidentata zone; (4) E. abneptis zone