Abstract <p>According to U‒Pb dating of zircon from granodiorites of the Brusnichnyi pluton of the Albazino gold deposit, the age of the pluton is 85.1 ± 0.6 Ma. According to the petrochemical peculiarities, the rocks belong to Na granitoids of the ilmenite series. The composition of rocks and the character of ore mineralization allow us to ascribe the Albazino deposit to reduced intrusion-related gold deposits with the adakitic type of ore-generating granitoids. The model of the formation of rocks suggests melting of metabasites at a pressure of &gt;10 kbar in the presence of garnet and amphibole/clinopyroxene in restite, as well as the involvement of carbon-bearing terrigenous rocks of an accretionary complex. Reduced granitoid magmas were the source of the fluid, which mobilized gold from the host rocks. The asthenospheric flows, which penetrated a broken subducted slab, could be an additional energy source necessary for melting of metabasites. The available data on similar Kutyn and Chulbatkan gold deposits allows us to distinguish a zone of gold-productive Turonian–Santonian granitoids of the ilmenite series in the region.</p>

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Ore-Generating Reduced Granitoids of the Albazino Gold Deposit, Khabarovsk Krai: Age, Geochemistry, and Petrogenesis

  • M. V. Kiselev,
  • I. A. Alexandrov,
  • V. V. Ivin,
  • V. V. Ratkin

摘要

Abstract

According to U‒Pb dating of zircon from granodiorites of the Brusnichnyi pluton of the Albazino gold deposit, the age of the pluton is 85.1 ± 0.6 Ma. According to the petrochemical peculiarities, the rocks belong to Na granitoids of the ilmenite series. The composition of rocks and the character of ore mineralization allow us to ascribe the Albazino deposit to reduced intrusion-related gold deposits with the adakitic type of ore-generating granitoids. The model of the formation of rocks suggests melting of metabasites at a pressure of >10 kbar in the presence of garnet and amphibole/clinopyroxene in restite, as well as the involvement of carbon-bearing terrigenous rocks of an accretionary complex. Reduced granitoid magmas were the source of the fluid, which mobilized gold from the host rocks. The asthenospheric flows, which penetrated a broken subducted slab, could be an additional energy source necessary for melting of metabasites. The available data on similar Kutyn and Chulbatkan gold deposits allows us to distinguish a zone of gold-productive Turonian–Santonian granitoids of the ilmenite series in the region.