Fluid Inclusions and CHOSPb Isotopes: Implications for the Genesis of the Zhuanshanzi Gold Deposit on the Northern Margin of the North China Craton

Abstract

The Zhuanshanzi gold deposit lies in the eastern section of the Xingmeng orogenic belt and the northern section of the Chifeng-Chaoyang gold belt. The gold veins are strictly controlled by a NW-oriented shear fault zone. Quartz veins and altered tectonic rock-type gold veins are the main vein types. The deposits can be divided into four mineralization stages, and the second and third metallogenic stages are the main metallogenic stages. In this paper, based on the detailed field geological surveys, an analysis of the orebody and ore characteristics, microtemperature measurement of fluid inclusions, the Laser Raman spectrum of the inclusions, determination of C H O S Pb isotopic geochemical characteristics, and so on were carried out to explore the origin of the ore-forming fluids, ore-forming materials, and the genesis of the deposits. The results show that the fluid inclusions can be divided into four types: type Igas-liquid two-phase inclusions; type IIgas-rich inclusions; type III-liquid inclusions; and type IV -CO 2 -containing threephase inclusions. However, they are dominated by type Ibgas liquid inclusions and type IVthree-phase inclusions containing CO 2 . The gas compositions are mainly H 2 O and CO 2 , indicating that the metallogenic system is a CO 2 H 2 O NaCl system. The homogenization temperature of the ore-forming fluid evolved from a middle temperature to a low temperature, and the temperature of the fluid was further reduced due to meteoric water mixing during the late stage, as well as a lack of CO 2 components, and eventually evolved into a simple NaCl H 2 O hydrothermal system. C H O S Pb isotope research proved that the ore-forming fluids are mainly magmatic water during the early stage, with abundant meteoric water mixed in during the late stage. Ore-forming materials originated mostly from hypomagma and were possibly influenced by the surrounding rocks, suggesting that the ore-forming materials were mainly magmatic hydrothermal deposits, with a small amount of crustal component. The fluid immiscibility and the CO 2 and CH 4 gases in the fluids played an active and important role in the precipitation and enrichment of Au during different metallogenic stages. The deposit is considered a magmatic hydrothermal deposit of middlelow temperature.Keywords: C H O S Pb isotope, metallogenic period and stage, microthermometry and laser Raman, ore-forming fluid, Zhuanshanzi gold deposit.

Fluid evolution and ore genesis of the Lianhuashan lode gold deposit, northern North China Craton: evidence from fluid inclusions and H–O–C–S–Pb isotopes

“…The decreasing δ 18 O H2O values from stages I to stage III imply involvement of meteoric water during ore formation. The δ 13 C PDB values of calcite samples are between −2.87 and −2.38‰, which are within the range of mantle carbon (−5 to −2‰; Deng et al 2015;Taylor 1986) and are comparable with those of other lode Au deposits in the NCC (Sun et al 2019;Zhu et al 2015). The low δ 18 O values may reflect significant addition of meteoric water (Fig.…”

Identification of Geochemical Anomalies Based on RPCA and Multifractal Theory: A Case Study of the Sidaowanzi Area, Chifeng, Inner Mongolia

“…62,63 The region is rich in mineral resources and features various types of mineralization, such as epithermal gold, skarn copper, and porphyry copper−molybdenum deposits. Mainly include the Zhuanshanzi gold, Dahuanghutong and Xujiashuiquan copper, 62,63 Baituyingzi molybdenum, 64 and Yajishan and Baimashigou copper−molybdenum deposits. 65,66 Gold deposits represented by Zhanshanzi gold deposit primarily occur in the Permian Yujiabeigou Formation rhyolites and Indosinian granites, exhibiting strong geochemical anomalies of Au and Ag.…”

“…The Chifeng-Kaiyuan deep fault extends from the southern part of the study area northeastward and was active multiple times from the Late Jurassic to the Early Cretaceous, resulting in a characteristic dense distribution of mineral deposits (prosepcts) along both sides of the fault. , The region is rich in mineral resources and features various types of mineralization, such as epithermal gold, skarn copper, and porphyry copper–molybdenum deposits. Mainly include the Zhuanshanzi gold, Dahuanghutong and Xujiashuiquan copper, , Baituyingzi molybdenum, and Yajishan and Baimashigou copper–molybdenum deposits. , Gold deposits represented by Zhanshanzi gold deposit primarily occur in the Permian Yujiabeigou Formation rhyolites and Indosinian granites, exhibiting strong geochemical anomalies of Au and Ag. Copper–molybdenum polymetallic deposits represented by Baimashigou copper–molybdenum deposit are mainly located in high Cu and Mo background areas and are speculated to be related to Mesozoic intrusive rocks and Jurassic strata. , …”