关键词: 中国东北部陆缘, 金矿床, 成因类型, 成矿时代, 地球动力学背景

Abstract:

Numberous endogenetic gold deposits are found in the epicontinental region in Northeast China, and they have attracted more attention and research efforts from both domestic and international economic geologists. These deposits are featured by the characteristic of complex and obviously multistage mineralization. Based on systematic study on geological features and metallogenic epoch of these endogenetic gold deposits in the area, the present paper has divided the gold deposits into four main types: mesothermal, contact-metamorphic, porphyry gold-copper and epithermal gold deposits. They were formed in three important ore-forming epochs at 170-160 Ma, 130-110 Ma and 110-90 Ma. Based on isotope geochemistry, we concluded that that the metallogenic material of the mesothermal gold deposit was derived from  the lower crustal source and its mineralization was closely related to lithospheric thinning and delamination of the continental margin, a processes triggered by the subduction of the PaleoPacific plate in the Early Mesozoic Yanshanian orogeny. The metallogenic material of the contactmetamorphic gold deposit was derived from the younger crust and the mineralization was relevant to contact metasomatism of magmatic process under extensional setting of the lithospheric thinning and delamination, which caused by the subduction of Paleo-Pacific plate. However, metallogenic material of porphyry gold-copper deposit and epithermal gold deposit manifested as crust-mantle mixture. Their mineralization occurred in the tectonic transition period from Asian continent subducted by the Paleo-Pacific plate towards the due north to the Izanagi-Farallon plate subduction toward west.

Key words: the continental margin of Northeast China, gold deposits, genetic type, metallogenic epoch, geodynamic settings