The server is under maintenance between 08:00 to 12:00 (GMT+08:00), and please visit later.
We apologize for any inconvenience caused
Login  | Sign Up  |  Oriprobe Inc. Feed
China/Asia On Demand
Journal Articles
Laws/Policies/Regulations
Companies/Products
ISOTOPIC COMPOSITIONS IN THE DONGBEIZHAI FINE DISSEMINATED GOLD DEPOSIT, SICHUAN RPOVINCE, AND THEIR GENETIC IMPLICATIONS
Author(s): 
Pages: 159-173
Year: Issue:  2
Journal: Chinese Journal of Geology(Scientia Geologica Sinica)

Keyword:  gold depositisotopic geochemistryfine-disseminated oreCarlin-typeDongbeizhaiSichuan;
Abstract: The Dongbeizhai gold deposit recently discovered in the northwestern area of Sichuan Province has its fine-disseminted ore bodies occurred in sedimentary carbonate-clastic formation. The ore bodies are strictly confined to the black rock layer of the sedimentary clastic formation by a major fault in this area. The ore-forming process in the deposit may be divided into three stages: (1) sedimentary-metamorphic, (2) percolation-hydrothermal(including two epoches, the main and the late epoches), and (3) superficial oxidation-leaching. Gold was concentrated mainly in super-microgr-ains in the hydrothermal stage. The hydrothermal mineralization is characterized by appearances of realgar, quartz, calcite, pyrite, with a minor amount of stibnite, arse-nopyrite and arsenic, etc.. Temperature of the hydrothermal fluids was in a range 220?to 120℃, and the mineralization depth is less 2km.The hydrothermal minerals in the Dongbeizhai gold deposit have their δ534S values - 5.8-6.3 (sulfides), δ18O values 15.1-27.2‰(quartz and calcite), and δ13C values -4.7-2.7‰ (calcite); hydrothermal fluids have δ18O values 12.8-16.7‰ (obtainedfrom isotope fractionation equation of calcite-water), δD values-66.6--75.5‰(fluidinclusions); initial ratio 87Sr/86Sr in the hydrothermal calcite is similar to that in the carbonate. Lead isotopic composition shows that the ore lead has its genetic relation with that in the carbonate rock.The above-described isotopic study shows that most of the ore-forming solutions was mainly derived from the ancient meteoric water; the amount of the hydrothermal fluids in mineralizing and altering systems was relatively small, sulfur in the fluids from the reduced sulfur in the country rocks, and the carbon predominantly from the carbonate layer and less from organic carbon in the black layer. The sedimentary carbonate rock was a main source for the metallogenic materials in ore. The hydrothermal mineralization took place in Yenshanian period. In the light of its geological features and genesis the Dongbeizhai gold deposit is believed to be the Carlin-type gold deposits
Related Articles
loading...