Tectonic Transformation and Metallogenesis of the Yanshan Movement during the Late Jurassic Period: Evidence from Geochemistry and Zircon U-Pb Geochronology of the Adamellites in Xingcheng, Western Liaoning, China

Abstract

The Yanshan Movement occurred mainly during the Middle-Late Jurassic, and gave rise to NE trending structures, magmatic events, volcanism and mineral resources. The transformation and evolution of the movement during the Middle-Late Jurassic were investigated from the rock assemblage, geochemistry, and chronology in adamellites which were exposed in the Xingcheng area, western Liaoning. Two types of adamellites were recognized—biotite adamellites with the formation age of 172–168 Ma and garnet-bearing adamellites of 158–152 Ma. All the samples of the two types of adamellites displayed enriched characteristics with high content of SiO2 (66.86–75.55 wt.%) and total alkali (Na2O + K2O = 7.56–8.71 wt.%), high large ion lithophile element (LILE: K, Rb, Sr), and low high field strength element (HFSE: Ce, Ta, P, Ti). The biotite adamellites belong to metaluminous-peraluminous I-type granites, and show volcanic arc granite characteristics, and were formed by partial melting of the ancient crust in the compressional setting that resulting from the subduction of the Paleo-Pacific plate beneath the north margin of the North China Craton (NCC). The garnet-bearing adamellites are also metaluminous-peraluminous I-type granites, with characteristics of both the compressional and extensional regimes, which were formed at the middle-late stages of the continuing subduction of the Paleo-Pacific plate, while simultaneously, the frontal side of the subduction slab began to roll back, leading to an extensional environment. Combining with regional geophysical studies and our petrological and geochemical studies, we propose that the eastern segment of the northern margin of NCC may have been controlled by the Paleo-Pacific tectonic domain at the latest in the Middle Jurassic, while the initiation of the tectonic regime from a compressional to an extensional environment was during the Late Jurassic (158–152 Ma) as a response of the Yanshan Movement. Simultaneously, geochronological statistics of the ore deposits in western Liaoning show that the Mesozoic endogenetic metalliferous deposits formed in a compressive environment influenced by the subduction of the Paleo-Pacific plate, similar to the magma events in ages, and the magmatism provided the thermodynamic condition and the source of metallogenic hydrothermal fluid for mineralization.

Identification and Geological Significance of Early Jurassic Adakitic Volcanic Rocks in Xintaimen Area, Western Liaoning

“…Trace elements were tested by an inductively coupled plasma mass spectrometer (ICP-MS Agilent 7500ce). Details of the analytical methods are given by Hu et al [60].…”

Origin of the dioritic porphyrite and its associated Matouniu skarn gold polymetallic deposits in the Eastern Hebei Province, North China: Evidence from geochronology, geochemistry, and C–O–S–Pb–Hf isotopes

“…Others suggested that the magmatism formed in an active compressive continental margin, induced by subduction of the Paleo-Pacific Plate beneath eastern China (Cisse et al, 2017;Hu et al, 2019;Shi et al, 2019;Xu et al, 2016;Zhu, Yang, & Wu, 2012).…”

“…178 Ma (Jiang et al, 2010;Tang et al, 2018;Xu et al, 2013), indicating that the thickening of the eastern NCC crust during the Middle Jurassic likely resulted from the compression induced by the subduction of the Paleo-Pacific Plate. There is consensus that the northern margin of the NCC underwent tectonic compression during the Jurassic, based on the large-scale thrust faults and folds (Wu et al, 2011) and the intense widespread Jurassic magmatism in the northern margin of the NCC (Dong et al, 2018;Fan et al, 2017;Hu et al, 2019). The northern margin of the NCC underwent extension during the Early Cretaceous, and is characterized by extensional rift basins (Meng, Hu, Jin, Zhang, & Xu, 2003;Ren, Tamaki, Li, & Zhang, 2002;Zhang, Zhao, Dong, & Yang, 2004), extensive detachment, normal faults (Zhang et al, 2004), and metamorphic core complexes (Davis et al, 1998;Wang et al, 2012).…”

“…The Eastern Hebei Province (Jidong or region) contains 29 gold deposits and 118 gold mineralization areas, hosting a proven gold reserve of $129.5 tonnes of Au, which constitutes 2.4% of China's total gold reserves (Liu, Shao, Liu, Zhang, & Wang, 2018;Song et al, 2016). Previous studies revealed that most of the deposits in the Jidong region were formed by Early-Middle Jurassic tectonic-magmatic-hydrothermal activity (Dong et al, 2018;Fan, Jiang, Xu, Hu, & Zong, 2017;Hu et al, 2019;Jiang, Jiang, Ling, & Ni, 2010;Tang, Xu, Wang, & Ge, 2018;Wu et al, 2011;Xu et al, 2013;Xu, Jiang, Fan, Hu, & Zong, 2016;Yang, Niu, Ren, & Li, 2015), but few studies have focused on Late Jurassic magmatism and mineralization in this region.…”

Introduction to the Special Issue “Role of Magmatic Activity in the Generation of Ore Deposits”

“…geochemical data indicate that the Kengdenongcuo rhyolitic tuffs, which host the deposit, originated along with contemporaneous syn-collision granitoids in the region due to arc-type magmatism as the Paleo-Tethys Ocean was closed. The contribution of Hu et al [6] concerns biotite adamellites, with the formation age of 172-168 Ma, and garnet-bearing adamellites of 158-152 Ma, which occur in the Xingcheng area of western Liaoning. Geochronologic studies of the ore deposits in western Liaoning show that these Mesozoic metalliferous deposits formed in a compressive environment influenced by the subduction of the Paleo-Pacific plate.…”