摘要
本文提出了额尔齐斯构造岩浆成矿域的新认识,进而划分成5个构造岩浆成矿带,总结了5种主要金矿类型。在对多拉纳萨依等9个典型矿床(点)作了较为详细的研究后,提出了阿尔泰金矿的多期次、多来源和多成因的区域成矿模式,并以示意图表达。
The Ertix tectono-magmatic metallogenic domain originated by the subductionof the North Tianshan-Junggar plate toward the Siberian plate in the Altay area,Xinjiang. It is composed of five tectono-magmatic metallogenic belts, i. e. trench,island arc, back-are basin, continental-margin plutonic-mgamatic are and intraplatevolcanic down-faulted basin, distributed from ocean crust to continental crust. Golddeposits occur in the five belts. On the basis of the geological-tectonic environments, wall rocks, occurrences ofore bodies, mineral assemblages, wall-rock alteration and geochemical characteristicsand in comparison with the ore-forming models of typical gold deposits at home and abroad, the Altay gold deposits are divided into five types: gold deposits inPrecambrian metamorphic rocks, gold deposits in Palaeozoic turbidites or carbona-ceous fine clastic rocks, gold deposits in volcanic rocks, gold deposits in hypabyssaldike rocks and hypabyssal--near--surface rocks and gold deposits in plutonic mag-matic rocks. These gold deposits were formed by hydrothermal metasomatism and filling,and are products of polyphase-polystage mineralization. The ore fluids of the majority of gold deposits are characterized by: 1) thedominance of Ca^(2+), K^+, Na^+, HCO_3^- and SO_4^(2-) for the liquid phase and the domi-nance of CO and CO_2 besides water vapour for the gas phase; 2) salinities of lessthan 10.0 wt% equivalent NaCl, densities of less than 1.0g/cm^3, a total dissolvedsolids content of 13.7--310.7 and a reduction parameter of 0. 12--17.02;3) tem-perafures of the main mineralization stage of 160--300℃ and ore formation pres-sures of 7. 34--70. 30MPa, 4) lgfo_2=--26 .5 to 48. 79 and lgfs_2=--6. 5--15. 5, and 5)pH values of 6.37--7.21 and Eh values of --0.60--0.8l(V). There are many sources of gold, but it chiefly comes from the original sourcebed in strata, particularly from the breakdown of gold-bearing minerals (such aspyrite) and the activation of gold;the water medium of the ore fluids has manysources, but it is mainly composed of meteoric water in the later stage. A regional metallogenic model.of polyphase, polystage, poly-genetic and poly-source Altay primary gold deposits controlled by the Ertix tectono-magmatic met-allogenic domain is put forward in this paper.
出处
《地质论评》
CAS
CSCD
北大核心
1993年第2期138-148,共11页
Geological Review
基金
"七五"国家重点科技攻关"75-56"项目I_3课题基金
关键词
金矿床
成矿模式
阿尔泰地区
gold deposit
regional ore--forming model
Altay
