Geochronological and mineralogical constraints on mineralization of the Hetai goldfield in Guangdong Province, South China

The genesis of gold deposits in the Hetai goldfield, South China: New constraints from geochronology, fluid inclusion, and multiple isotopic studies

“…Because of the low fractionation factor of hydrogen isotopes between minerals and water at low temperatures (<330°C), the δD values of minerals were regarded as representing those of mineralizing fluids (Zhao & Zheng, ; Y. F. Zheng & Chen, ). The temperatures used in calculation are the peak values of fluid inclusion homogenization temperatures for intermediate (518.5 K) and late (480.5 K) substages, which is also consistent with the temperature from mineral geothermometers (Jiao, Deng, et al, ). The calculated δ 18 values of fluids coexisting with altered minerals of auriferous cataclastic ore (intermediate substage) range from 5.47‰ to 7.46‰ with a mean value of 6.73‰.…”

“…197°C to 214°C; Table ) and chlorite thermometry (ca. 230°C to 260°C) from the hydrothermal intermediate substage (Jiao, Deng, et al, ), are lower than the argon closure temperature in mica (300°C−350°C; McDougall & Harrison, ), the present 40 Ar/ 39 Ar age can also be reliably interpreted as the timing of hydrothermal alteration and gold deposition for the Hetai goldfield. This new age is roughly in accordance with previously reported 152.5 ± 3.1 Ma of hydrothermal zircons U–Pb age (Zhai et al, ) and 157.1 ± 1.0 Ma of sericite 40 Ar/ 39 Ar age (C. Wang, Zhang, et al, ) of ore‐bearing rocks from the same deposit, which suggests that the Hetai goldfield formed during the Late Jurassic.…”

“…Here, we choose the former temperature group as mineralization temperature, which is congruent with a temperature range of ca. 290°C to 350°C estimated from arsenopyrite thermometry for the same stage (Jiao, Deng, et al, ). For the type 2b fluid inclusions, the measured first melting temperatures of solid CO 2 vary from −79.2°C to −56.6°C with most of them slightly lower than the triple point for pure CO 2 (−56.6°C), suggesting the presence of minor other components such as CH 4 as indicated by laser Raman spectroscopy analyses.…”

“…The Qin–Hang metallogenic belt (QHMB) is one of most important metallogenic belts in South China (Figure a). Geotectonically, the QHMB covers the range of the Qinzhou Bay–Hangzhou Bay Juncture Orogenic Belt, which has been interpreted as a giant tectonic suture between the Yangtze and Cathaysia blocks of South China, and has experienced multiple phases of tectonic disturbances associated with numerous metal deposits of various scales, including one rifting event in the Neoproterozoic and several tectonic events in the Phanerozoic, such as Caledonian, Indosinian, and Yanshanian orogenies (Jiao, Deng, et al, ; Z. X. Li et al, ; Pirajno & Bagas, ; Shu, Faure, Yu, & Jahn, ; L. Wang et al, ; G. W. Zhang et al, ). The QHMB can be divided into the northern (N), middle (M), and southern (S) sections (Figure a), which are endowed with the predominant mineral resources of Cu–Fe, W–Sn, and Au–Ag, respectively (Mao, Cheng, Chen, & Pirajno, ; Y.…”

Ductile shear deformation and gold mineralization in the Hetai goldfield of the Yunkai Massif, South China Block

“…Previous researchers have carried out many studies on the HGF, proposing different views and performing transdisciplinary studies on its stratigraphy, tectonic deformation, radioactive age as well as pressure‐temperature condition of its inclusions (He & Zhang, ; L. Li et al, 2000). For example, the origin of the HGF was reported to have resulted from the subduction of the Yunkai Massif beneath the Indosinian block during the Triassic (K. Zhang & Cai, ; Jiao, Wang, et al, ; Jiao, Deng, et al, ) or the oblique subduction of the Paleo‐Pacific Plate beneath the South China Block during the Early Jurassic (Cai, ); its ore‐forming age has been reported to be Caledonian, early Yanshanian, or middle‐later Yanshanian (J. Chen, ; C. Wang, Zhang, Wang, Qiu, & Gong, ). The process of ductile shear has been reported to have contributed greatly to gold mineralization.…”