Low‐Temperature Thermochronology for Defining the Tectonic Controls on Heterogeneous Gold Endowment Across the Jiaodong Peninsula, Eastern China. Issue 1 (19th January 2023)

• Record Type: Journal Article
• Authors: Qiu, Kun‐Feng; Deng, Jun; Sai, Sheng‐Xun; Yu, Hao‐Cheng; Tamer, Murat T.; Ding, Zheng‐Jiang; Yu, Xue‐Feng; Goldfarb, Richard
• Is Part Of: Tectonics. Volume 42:Issue 1(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2023-01-19
• Subjects: low‐temperature thermochronology -- structural analysis -- heterogeneous gold endowment -- Mu‐Ru gold district -- Jiaodong gold province; Geology, Structural -- Periodicals; 551.8
• DOI: 10.1029/2022TC007669
• Languages: English
• ISSNs: 0278-7407

Abstract

Abstract: This study presents a low‐temperature thermochronological data set from the Jiaodong Peninsula in eastern China, including new zircon U‐Th/He and apatite fission‐track data from the Sulu Terrane in the eastern side of the Jiaodong Peninsula and published data from the Jiaobei Uplift to the west. These data reveal differential tectonic evolution between the Jiaobei Uplift and the Sulu Terrane, which is responsible for their heterogeneous gold endowment. Thermal history inverse modeling and structural analysis indicate three broad periods of cooling in the Sulu Terrane. These include: (a) slow cooling from 114 to 50 Ma; (b) rapid cooling from 50 to 40 Ma; and (c) tectonic stability after 40 Ma with little cooling. This thermotectonic evolution pattern shows that the local tectonic evolution of Sulu Terrane and Jiaobei Uplift are relatively independent, although they share identical far‐field geodynamic controls. The critical characteristic is the Early Cretaceous extension within the Sulu Terrane was much weaker than that in the Jiaobei Uplift that underwent a rapid period of uplift in the Aptian. The differential tectonic evolution of the two areas induced variation in structural architecture and consequential differences in degree of extension that are important factors in defining the heterogeneous gold endowment rather than simply suggested differences in ore‐forming fluid chemistry, metal precipitation mechanism, and/or exhumation levels. The intense extension in the Jiaobei Uplift was conducive to voluminous fluid migration and gold precipitation. In contrast, the much weaker extensional setting in the Sulu Terrane was not conducive to large‐scale fluid migration from deep. Plain Language Summary: The Izanagi Plate was subducted westward underneath the Eurasian continent beginning in the Jurassic, influencing the tectonic evolution and forming a remarkable metal endowment in eastern China. The Jiaodong gold province in China is composed of the Jiaobei Uplift to the west and Sulu Terrane to the east, hosting gold resources of >5, 000 tonnes. More than 85% of the gold resources are hosted in orogenic gold deposits in the Jiaobei Uplift, whereas gold endowment is more limited in the Sulu Terrane. Structural analysis and low‐temperature thermochronology from our new study reveal that the tectonic evolution of the Sulu Terrane is different from that previously described for the Jiaobei Uplift. Differential tectonic evolution shows that the local ore‐controlling structural evolution of the two areas is relatively independent although both are controlled by the subduction of the Izanagi Plate. This independence reflecting differences in degrees of extension appears to be the major factor responsible for the heterogeneous gold endowment in the Jiaodong gold province. The greater amount of extension in the Jiaobei Uplift relative to that in the Sulu Terrane was more conducive to large‐scale fluid migration in the Early Cretaceous, which led to the world‐class gold deposit formation. Key Points: Structural analysis and low‐temperature thermochronology reveal three cooling episodes in the Sulu Terrane since the Aptian The tectonic evolution of the Sulu Terrane is different from that of the Jiaobei Uplift Tectonic independence‐induced differences in extensional degrees led to extreme variability in gold endowment across the Jiaodong Peninsula