Precambrian Important Tectonic Events In The Central And West Part Of North Margin, North China Platform

Based on a research project from China Nuclear Industry Geological Bureau, the author described the geological features of the large-scale deposits which occur in the precambrian strata in the central and western part of North Margin in north china platform, and divided four major metallogenic events, they are Neo- archean metallogenic geological events, Paleoproterozoic metallogenic geological events (2500 ~ 1800Ma), Mesoproterozoic metallogenic geological events (1800 ~ 1000Ma) and Paleozoic ~ Mesozoic metallogenic geological events (543~65Ma).(1) Neoarchean metallogenic geological events are mainly for the 2700Ma basic volcanism, 2500Ma acidic magmatism and strong and widely development of metamorphism; this stage mainly formed gold deposits in Archean granite-greenstone belt, banded iron deposits, and the graphite deposits which occur in high-grade metamorphic rocks.(2) Paleoproterozoic metallogenic geological events mainly took place in 2350~2100Ma and 2100~1800Ga orogenic events during the period, with a large number of magmatic activity, the NeoArchean granite-greenstone belt was modificated and superposed, which was bringing gold into the granite-greenstone belt, and gold deposits formed such as the Paishanlou gold deposit; Proterozoic is an important period of forming lead-zinc mineralization, in the region Caijiaying business lead-zinc deposit formation and the period is closely related to tectonic events.(3) Mesoproterozoic metallogenic geological events is the most important metallogenic event in the study area, mainly for the north of ancient continent of cracking events in the early Mesoproterozoic (1800Ma~1300Ma) and the splitting event in the late Mesoproterozoic (1300Ma~1000Ma), and formed two big taphrogenic trough of Langshan-Zha'ertaishan rapture and Bayan Obo rapture. This time produced a large number of deposits, such as the Bayan Obo Nb-Fe deposit, Wolf Mountain-Zha'ertaishan Sulphur polymetallic ore belt, Gao banhe lead and zinc-pyrite deposit, Temple of vanadium and iron deposits and manganese ore bed and so on.(4) Paleozoic ~ Mesozoic metallogenic geological events is mainly formed in the previous structure to transform the substrate, cracking and put together, accompanied by strong magmatic intrusion into the activities and accompanied by the intrusion of minerals, particularly the stage of Yanshanian and Hercynian, the magmatic acted very abnormal and frequently. This period formed Dongping gold deposit, yu'erya gold deposits and so on.The mining area of gold, copper and lead-zinc, manganese, iron ore, rare-earth ore in the Precambrian strata of study area are mainly controlled by deep faults and magmatic rocks. Xinghe graphite mine only closely related with the regional metamorphism of the Precambrian, its formation mainly impacted by sedimentary environmental. Deposits in the region are multi-phase nature, cascade, especially the gold deposit.