Characteristics And Genesis Of Magmatic Rocks Of Laoheishan And Jinchang Area, Heilongjiang Province

The study area was located in the southeast of Heilongjiang Province and in the southwest of Jiamusi- Xingkai Block, and located in the second uplift belt in the Laoye mountain uplift tectonic position-the east Pacific ridge uplift which was in shore of ancient Asia ocean tectonic domain and the Pacific tectonic domain superimposed transformation. The magmatic activity was strong, and ore-forming condition was superior in this study area because of the multiphase tectonic activities. So this area was significant vision of gold and polymetallic metallogenic province.The ore types and structures and the characteristics of paragenetic associations in the study area were found out in this research. The connection between strata and magmatic rocks were analyzed, and quantitative analysis for the intrusive rock in the study area was studied by combined petrology, geochemistry and relevant tests. And the nature of the ore-forming fluid the material source and genesis of evolution were carried on by comprehensive analysis.Comparing the magmatic evolution of the Laoheishan area and the Jinchang area, the research showed the following conclusions.(1) Intrusive rocks in the Laoheishan area should be divided into late Indosinian period and Yanshan period, and the late Indosinian period was subdivided into diorite, granodiorite, and monzonitic granite three phases, and middle Yanshan period was subdivided into monzonitic granite and orthoclase granite.(2) Diorites in the Laoheishan area of late Indosinian period were derived from the mantle, which was a more basic mantle magmatic injection acid fast cooling crystallization of magma which formed in the ancient Asia ocean tectonic domain closed stretch after collision tectonic environment. The granodiorite and monzonitic of late Indosinian period were derived from the mantle and the crust. The granodiorite was formed under the environment of subduction extrusion and monzonitic was formed under the environment after tectonic transformation system. Middle Yanshan period magmatic material derived from the primitive mantle and crustal material contamination in magma evolution, which was formed in the squeezing tectonic environment.(3) The Laoheishan area and the Jinchang area had same magmatic evolution and formed under the same tectonic environment. But in the middle of Yanshan period, the two areas had different magmatic material sources.