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Liu X.L.,China University of Geosciences | Liu X.L.,Chinese Academy of Geological Sciences | Wang Y.T.,Chinese Academy of Geological Sciences | Hu Q.Q.,Chinese Academy of Geological Sciences | And 5 more authors.
Acta Petrologica Sinica | Year: 2014

The Chaima gold deposit is located on the northwest of the Fengtai ore concentration area in Shaanxi Province and 0.5 km west to the super-large Baguamiao gold deposit. They are similar in metallogenic geological environment and ore-control conditions. There are five ore-bearing zones in this deposit and their occurrence is controlled by lithology and tectonic. The ores are quartz-vein type and altered-rock type, in which the first is the main type. The gold mineralization of Chaima gold deposit could be divided into three stages: the early quartz-carbonate stage, the second and main quartz-carbonate-sulfide stage and the late quartz stage. In this paper, the Sm-Nd isotopic dating is carried out on the calcite and dolomite from the main stage, yielding an isochron age of 203.2 ± 1.6Ma, which shows that the deposit formed in Late Triassic. Combined with the previous research on the gold deposits, magmatite and tectonic movements of the area, we suggest that the Chaima gold deposit is an orogenic gold deposit formed after the collision of Qinling in Late Indosinian.


Hu Q.Q.,China University of Geosciences | Hu Q.Q.,Chinese Academy of Geological Sciences | Wang Y.T.,Chinese Academy of Geological Sciences | Wang R.T.,Northwest Geological Exploration and Mining Bureau for Nonferrous Metals | And 3 more authors.
Acta Petrologica Sinica | Year: 2012

The Bafangshan-Erlihe Pb-Zn deposit is located on the northwest of the Fengxian-Taibai ( abbreviated Fengtai) ore concentration area, and the orebodies mainly occur at the contact zone between the Gudaoling Formation of Middle Devonian and the Xinghongpu Formation of Upper Devonian, controlled by NWW-trending Bafangshan-Erlihe anticline. In this paper, the Rb-Sr isotopic dating is carried out on the sphalerite from the main mineralization stage of the Erlihe Pb-Zn deposit, yielding an isochron age of 220.7 ± 7.3Ma, showing that the deposit formed in Late Triassic, and the age data is also a constraint on the Pb-Zn ore-forming time of the whole Fengtai ore concentration area. The Sr/ Sr: value of the sphalerite is 0.714145 ±0.000031, indicating that the ore-forming materials are mainly derived from the continental crust. In the context of regional geology, we suggest that the Erlihe Pb-Zn deposit is the product of the regional intensive tectono-magmatic-mineralization processes developed in the Fengxian-Taibai ore concentration area in Triassic.


Wang R.T.,Chang'an University | Li F.L.,Wuhan University | Chen E.H.,No. 717 Party of Northwest Geological Exploration and Mining Bureau for Nonferrous Metals | Dai J.Z.,Northwest Geological Exploration and Mining Bureau for Nonferrous Metals | And 2 more authors.
Acta Petrologica Sinica | Year: 2011

Bafangshan-Erlihe large lead and zinc ore deposit has metallogenic characteristics of hydrothermal sediment and paulopost reforming, but the distribution of REE, B, Ba, Tl and other elements has not wholly clear submarine exhalative feature, also that indicates the deposit has a far distance to exhalative center. Homogenizalion temperature of quartz fluid inclusion, FeS molecule percent and Ga/Ge atom ratio in sphalerite all showed mineralization temperature was 200 ∼ 340°C, middle and high temperature dominated, Homogenization temperature of calcite fluid inclusion is 80 ∼ 160°C and 160 ∼ 260°C, which reflected the reformation process of two hydrothermal events. The zircon of mineralized silicalite in the ore region has the same feature with detrital zircon, its U-Pb isotope age disperses in 400 ∼ 1800Ma, that don't represent the formation age of silicalite or Bafangshan-Erlihe large lead and zinc ore deposit, the existence of a lots of detrital zircon proved metallogenic environment was offshore genesis. The formation age of dioritized porphyrile that cut ore body is 214 ± 2Ma, and the formation age of granite-porphyry near Erlihe ore region is 217.9 ± 4.5Ma. The two dikes are production of Late Indosinian movement. The dioritized porphyrite transected ore body and microquartzite, which indicated mineralized reformation happened before the dike formed. Orebody enriched in the arch of anticline, which showed reformation mainly occurred during fold process, namely. Early Indosinian movement was mineralized reformation epoch, possible between Early and Late Indosinian movement. The formation of Bafangshan-Erlihe large lead and zinc ore deposit went through hydrothermal sediment and structure reformation two stages, metal elements initially enriched in Middle Devonian stratum in sedimentary stage, which provided substances source for later structure reformation. It concludes the ore deposit genesis belongs to basement hydrothermal exhalative sedimentary-tectonic magma reformation type. The main ore-controlled structure included synsedimentaiy anticline, syngenetic fault that was hydrothermal transportation pathway and local sedimentary basin where ore-forming substances sedimented and enriched in this lead-zinc ore region. Synsedimenlary limestone anticline, the contacted bell of limestone with phyllile, and "organic reef- silicaliteargillite" suite in silicalite or carbonate rock stratum area are more direct and very important prospecting criteria. The most economic and reserve perspective target for enlarging exploration in Bafangshan-Erlihe lead and zinc ore region is TEM geophysical anomaly position that located the south limb of main anticline, where is the best exploration target for prospecting superseded resources to mine.

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