THE MAIN CHARACTERISTICS OF THE UPPER PALAEOZOIC STRATIGRAPHY AT THE NORTH NADANHADA RANGE,HEILONGJIANG PROVINCE, CHINA
Li Wenkang;Han Jianxiu;Zhang Shuxin;Meng Fanyi Shenyang Institute of geology and mineral resources
In The Nadanhada Range, there crops out a thick sequence of marine sediments with in-terbedded volcanic rocks, which in 1959 was named as Erdaohezi Group and assigned to Meso-zoic on the ground of some Radiolaria collectes by M. G. Organov, I.N. Grolov and Wang Xi-uzhang. Since then, this region was considered tectonically a Mesozoic geosyclinal folding belt.However, during their field work carried out in the last two years in this region, the writersfound besides Radiolaria many Fusulinids and Corals in the sediments. A thorough study of the-se has proved that the strata containing these fossils are of late Paleozoic age. Therefore, anew column is proposed as shown in tab1e 1 (in Chinese). The oldest Paleozoic strata, namedas Dadaihe group, distributed in the axial part of anticlinorium along the Wusuli River, aresupposed to be of Devonian to lower Carboniferous age without convincing paleontological evi-dence. Conformably overlying them is the Erlianqiao Formation of middle Carboniferous, carry-ing in addition to Radiolaria also corals and abundant fusulinids such as Profusulinella, Fusuli-nella, Eostaffella. Further upward is the upper Carboniferous Banmiaogou Formation containingcorals and fusulinids such as Triticites, Pseudoschwagerina, Paraschwagerina, Chalaroschwagerinaetc. The uppermost is Dondagou Formation lower Permian. containing Nagatoella, Misellina inits lower part and Neoschwagerina, Reichelina, Kahlerina, Rauserella, Pseudodoliolina in the upperpart. The so-called Nadanhada Mesozoic Geosyncline Folding Belt is no longer supported byany evidence.