Thermochronology of Pangxidong Fault Zone in Southern Section of Qin-Hang Metallogenic Belt
Ding Ruxin
Yu Pengpeng
Hu Guangming
Zou Heping
Zeng Changyu
Zhou Yongzhang
Abstract：The Pangxidong fault zone is one of many NE-strength ductile shear zones in the southern section of the Qin-Hang metallogenic belt and controls the distribution of a series of ductile shear zones related Ag-Au deposits.Study on its thermo-chronology is helpful to understand the tectonic evolution of the NE-trending ductile shear zone in the southern part of the Qin-Hang metallogenic belt and its effect on the associated mineral deposits.A set of muscovite 40Ar/39Ar and fission track analysis were carried out in this paper.Two muscovite samples from the mylonite yielded 40Ar/39Ar isotopic total gas ages of 221.98± 1.16 Ma and 223.77±1.16 Ma,respectively.It is interpreted that the ductile shearing happened in Pangxidong fault zone during the Indosinian period,which is believed to have provided favorable space for the formation of associated mineral deposits.Apa-tite and zircon fission track ages from the same mylonite sample yield 64.83±4.13 Ma and 75.69±2.88 Ma,respectively.Com-bined with the thermal history modeling results,it is shown that the fault zone had experienced a rapid cooling process during~75—60 Ma(6.2 ℃/Ma),which is much different from the slow cooling process of the Yunkai region (1.5 ℃/Ma).The re- sults suggest that the Pangxidong fault zone was active again during ~75—60 Ma and the Pangxidong Ag-Au deposits possibly formed in the Late Cretaceous.
Keywords：Qin-Hang metallogenic beltPangxidong fault zone40Ar/39Ar datingfission track analysispetroleum geology
Publication Date：2018-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：9( 1830-1838 )