Ore geology and fluid inclusion geochemistry of the Tiemurt Pb-Zn-Cu   deposit, Altay, Xinjiang, China: A case study of orogenic-type Pb-Zn   systems

doi:10.1016/j.jseaes.2011.11.019

CORC > 北京大学 > 地球与空间科学学院

	Ore geology and fluid inclusion geochemistry of the Tiemurt Pb-Zn-Cu deposit, Altay, Xinjiang, China: A case study of orogenic-type Pb-Zn systems
	Zhang, Li ; Zheng, Yi ; Chen, YanJing
刊名	journal of asian earth sciences
	2012
关键词	Tiemurt Pb-Zn-Cu deposit Fluid inclusion CO2-rich fluid Orogenic lode deposit Altay orogenic belt AU-MO DEPOSIT GOLD DEPOSITS INNER-MONGOLIA HENAN PROVINCE METALLOGENIC SYSTEMS NW CHINA ISOTOPE CONSTRAINTS MINERALIZATION GENESIS
DOI	10.1016/j.jseaes.2011.11.019
英文摘要	The Tiemurt Pb-Zn-Cu deposit is hosted in a Devonian volcanic-sedimentary basin of the Altay orogenic belt, and is thus interpreted to have formed by sea-floor hydrothermal exhalation in previous studies. Our investigation discovered that the deposit is not stratiform or stratabound, but structure-controlled instead. The hydrothermal ore-forming process can be divided into the early, middle and late stage, represented by pyrite-quartz, polymetallic sulfide-quartz and carbonate-quartz veinlets, respectively. The early-stage veins and contained minerals are structurally deformed and brecciated, suggesting a compressional or transpressional tectonic regime. The middle-stage veinlets intrude and infill the fissures of the early-stage assemblages, and show no deformation, suggesting a tensional shear setting. The late-stage veinlets mostly infill open-space fissures that crosscut veins and replacements formed in the earlier stages. Four types of fluid inclusions (FIs), including aqueous (type W), carbonic-aqueous (type C), pure carbonic (type PC) and solid-bearing (type S), are identified at the Tiemurt deposit. The early-stage minerals contain the C- and W-type primary FIs that are totally homogenized at temperatures of 330-390 degrees C with low salinities of 0.8-11.9 wt.% NaCl eqv.; whilst the late-stage quartz or calcite contains only the W-type FIs with homogenization temperatures of 118-205 degrees C, and salinities of 1.4-3.4 wt.% NaCl eqv. This indicates that the ore fluid system evolved from CO2-rich, probably metamorphic to CO2-poor, meteoric fluids; and that a significant CO2-escape must have occurred. All the four types of FIs can be only observed in the middle-stage minerals, and even in a microscopic domain of a crystal, representing an association trapped from a boiling fluid system. These FIs homogenize at temperatures ranging from 270 to 330 degrees C, with two salinity clusters of 1.9-14.5 and 37.4-42.4 wt.% NaCl eqv., respectively. This implies that metal precipitation resulted from fluid boiling, CO2-escape and transient oversaturation. The estimated trapping pressures of FIs range from 130 to 380 MPa, suggesting an alternating lithostatic-hydrostatic fluid-system, controlled by a fault-valve at the depth of 13 km. Therefore, the Tiemurt Pb-Zn-Cu deposit is likely an example of orogenic Pb-Zn + Cu systems formed in collision orogeny, rather than a pre-collision VMS or Sedex system developed in Devonian; and a new metallogenic model is proposed to interpret the formation of the Tiemurt Pb-Zn-Cu deposit. (C) 2011 Elsevier Ltd. All rights reserved.; Geosciences, Multidisciplinary; SCI(E); 0; ARTICLE; ,SI; 69-79; 49
语种	英语
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/235514]
专题	地球与空间科学学院
推荐引用方式 GB/T 7714	Zhang, Li,Zheng, Yi,Chen, YanJing. Ore geology and fluid inclusion geochemistry of the Tiemurt Pb-Zn-Cu deposit, Altay, Xinjiang, China: A case study of orogenic-type Pb-Zn systems[J]. journal of asian earth sciences,2012.
APA	Zhang, Li,Zheng, Yi,&Chen, YanJing.(2012).Ore geology and fluid inclusion geochemistry of the Tiemurt Pb-Zn-Cu deposit, Altay, Xinjiang, China: A case study of orogenic-type Pb-Zn systems.journal of asian earth sciences.
MLA	Zhang, Li,et al."Ore geology and fluid inclusion geochemistry of the Tiemurt Pb-Zn-Cu deposit, Altay, Xinjiang, China: A case study of orogenic-type Pb-Zn systems".journal of asian earth sciences (2012).