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Precambrian cratons and Phanerozoic orogens: gold metallogeny of China
Published in Adam Piestrzyński, Mineral Deposits at the Beginning of the 21st Century, 2001
R.J. Goldfarb, Taihe Zhou, S.L. Garwin, Jingwen Mao, Yumin Qiu
The North China (NCC), Yangtze, and Tarim cratons underlie about half of China (Fig. 1) and are dominated by Late Archean and Paleoproterozoic rocks. Subsequent to Neoproterozoic rifting from Rodinia, these three cratonic blocks occurred as microcontinents within the Paleo-Tethys Ocean throughout almost the entire Paleozoic (Metcalfe, 1996). No gold deposits are recognized to have formed within these blocks as they migrated across the ocean basin, and if any auriferous shallow-level, oceanic arc hydrothermal systems were present, then they were likely lost to erosion during later collision with the growing Pangea supercontinent.
Intermittent subduction of the Paleo-Tethys Ocean in the middle–late Permian: evidence from the mafic–intermediate intrusive rocks in the East Kunlun Orogenic Belt
Published in Australian Journal of Earth Sciences, 2021
J. Sun, Y. Qian, Y. Li, H. Li, S. Tian, F. Sun
In combination with previous research, our analyses allow us to draw the following conclusions regarding the evolution of the Paleo-Tethys Ocean in the EKOB. (1) Subduction of the Paleo-Tethys Ocean began at ca 277.7 Ma (Figures 14 and 15a) (Liu et al., 2014). (2) During the period ca 266–255 Ma, East Kunlun was in a backarc extension setting, probably triggered by slab roll-back (Xin et al., 2019). The melts originated from lithosphere-enriched mantle with metasomatism by slab fluids, producing the source for the gabbros. Some mafic–ultramafic layered intrusions were also generated in the EKOB at this time (Figures 14 and 15b) (Hu et al., 2018). (3) Resubduction of the Paleo-Tethys Ocean began during the late Permian to Middle Triassic (252–242 Ma). The lithosphere-enriched mantle with metasomatism by slab melts produced the magma source for gabbrodiorites during this time (Figures 14 and 15c). In addition, a significant amount of arc-related magmatic rocks was produced in the EKOB. (4) The Paleo-Tethys Ocean closed during the Middle to Late Triassic (<242 Ma). This led to the widespread formation of magmatic rocks with syn-collision and post-collision properties in the EKOB (Figures 14 and 15d) (Chen et al., 2018).
The geological process for gas hydrate formation in the Qilian Mountain permafrost
Published in Petroleum Science and Technology, 2019
Zhengquan Lu, Gangyi Zhai, Yinhui Zuo, Quanfeng Wang, Dongwen Fan, Shiqi Tang, Daodong Hu, Hui Liu, Ting Wang, Youhai Zhu, Rui Xiao
In the early Paleozoic era, it was a small oceanic basin located between the Qaidam massif and the North China massif in the Qilian Mountain permafrost. Due to the Caledonian movement in the late Silurian period, the ancient oceanic basin development ceased and the uplift and erosion occurred. It began to subside during Carboniferous period, leading to sedimentation within a wide epicontinental shelf. In Permian period, it went up and down differentially in the south and the north: it became a continent due to uplift in the northern Qilian Mountain, and remained an epicontinental shelf or an epeiric sea environment in the southern Qilian Mountain. In Triassic period, it was still a sea basin environment in the southern Qilian Mountain, forming a deposition of marine sand-mudstone inter-bedded with limestone. At the end of Late Triassic period, the Paleo-Tethys Ocean closed due to the Indosinian movement, and the entire Qilian Mountain uplifted to become a continent and an eroded area (Fu and Zhou 1998). The early Yanshan tectonic movement exerted local extension on the Qilian Mountain to form some banded intra-mountain faulted depressions, with a set of deposition of Jurassic intra-mountain lacustrine and swamp facies of coal-bearing clastic rocks, constituting a series of small coal-bearing basins in a discontinuous band of NW-SE direction. The coalfield of Muli is the largest in Qinghai. It covers an area of about 650 km2, containing the major mining areas of Juhugeng, Hushan, Jiangcang and Reshui (Wen et al. 2011).