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The formation and evolution of the ancient continental crust are crucial issues in solid-earth geology which are commonly associated with global tectonic events and the formation of economically valuable magmatic-hydrothermal ore deposits. The Cathaysia Block, one of the ancient continents in Southeast Asia, can be subdivided into two parts: the West Cathaysia Block and the East Cathaysia Block. Unlike the East Cathaysia Block, no Precambrian rocks are exposed in the West Cathaysia Block, constraining further understanding of the formation and evolution of this block. In this study, a total of four hundred and thirty-three zircon U-Pb dating analyses and two hundred and eighteen Lu-Hf isotopic analyses on zircon grains from the Jurassic Dengfuxian granites and Ordovician Tanghu granites, Nanling Range, were carried out. LA-ICP-MS zircon U-Pb dating yields mean average 206Pb/238U ages of 152.6 ± 2.2 Ma (MSWD = 1.6) and 442.4 ± 1.7 Ma (MSWD = 3.8), which are regarded as the rock-forming age for the Jurassic Dengfuxian granites and Ordovician Tanghu granites, respectively. The 207Pb/206Pb ages of the inherited zircons from the Jurassic Dengfuxian granites and Ordovician Tanghu granites range from 522 Ma to 3395 Ma, hosting two major peaks at the 0.9–1.0 Ga and 2.4–2.5 Ga. In contrast to the East Cathaysia Block, the West Cathaysia Block lacks the age peak of 1.8–1.9 Ga, indicating that the West Cathaysia Block was not influenced by the assembly of the Columbia supercontinent in the Paleo-Proterozoic. In combination with the Lu-Hf isotopes, we proposed that the crust evolution of the West Cathaysia Block in Archean is dominated by juvenile crustal growth events, and dominated by the crustal reworking since the Proterozoic. The long duration of crustal reworking in the West Cathaysia Block resulted in the enrichment of lithophile elements (e.g., W, Sn, Nb, and Ta) in the crust of that region. Therefore, the Jurassic granites in the Nanling Range, which are mainly derived from the partial melting of Proterozoic basement rocks, became associated with large-scale tungsten polymetallic mineralization. [ABSTRACT FROM AUTHOR]

The Taiyuan Formation, located on the northern margin of the Ordos Basin, has an important role in reconstructing tectonic paleogeography and evolutionary process due to its preservation of information about the tectonic evolution of the basin throughout the Late Paleozoic. The provenance, paleogeography, and tectonic activity traits of the Taiyuan Formation were examined using the sedimentary petrology and zircon chronology methods. The Alxa block is consistent with the dating results of the Taiyuan Formation in Shabatai, and the Daqing Shan is consistent with the results of the Taiyuan Formation in Xiachengwan and Adaohai. It is inferred that the provenance of the Taiyuan Formation in the western part of the northern margin of the basin is from the Alxa block, and the provenance in the eastern part is from the Daqing Shan when combined with the study of sandstone detrital components, and paleocurrent. In the late Paleozoic, the Siberian plate collided with the North China Craton, and the Taiyuan Formation was deposited in the northern margin of the Ordos Basin. However, on account of the different ages and types of basement rocks and the central paleo-uplift which has not completely disappeared, the Taiyuan Formation has obvious east-west zonation. [ABSTRACT FROM AUTHOR]

The Taoxi dome stands out as a rotated-circular structure on maps of the Wuyi terrane, south China. The origin and tectonic activity analysis of the Taoxi dome is a window to understand the tectonic framework and aggregation process of the Wuyi terranes in the Cathaysia block. Our field observations demonstrated that two major phases of deformation, counterclockwise rotation and dome uplift, were recorded in the Taoxi dome. Geochronological data indicated that the counterclockwise rotation was initiated at about 422 Ma as a result of a sinistral slide collision between the North Wuyi terrane and the South Wuyi terrane along the Nanping–Ninghua tectonic belt during the Caledonian. Zircon dating ages of the intrusions developed in the Taoxi dome suggested that the Taoxi dome had undergone at least two strong upheavals and the uplift of the Taoxi dome was active during the periods 229–222 Ma and 158–100 Ma. Geochemical data indicated that the intrusions developed in the Taoxi dome had characteristics of high silica (SiO2 > 70 wt.%) and belonged to the A2-type granites, which suggest that the Taoxi dome was long governed by a tectonic setting of post-collisional or anorogenic magmatism since the Caledonian. The strong movement of the Caledonian rotation and coeval strike-slip movement in the Wuyi terranes suggests that a slide rotation may have been a major characteristic in response to the rifting process of micro-terranes during the late Paleozoic in the Cathaysia block. [ABSTRACT FROM AUTHOR]

The tectonic evolution of the Qinling orogen is key to understanding the process of convergence between the North China Block (NCB) and the South China Block (SCB). The Wuguan Complex and Liuling Group, situated along the southern margin of the Shangnan–Danfeng suture zone (SDSZ) between the North Qinling Terrane (NQT) and the South Qinling Terrane (SQT), are important indicators of the late Paleozoic tectonic evolution of the Qinling orogen. In this paper, the detrital zircon U–Pb geochronology and geochemical analysis of the Wuguan Complex and Liuling Group are carried out. Detrital zircons from two metasedimentary rock samples of the Liuling Group yield a major age peak at 460 Ma and two subordinate peaks at 804 Ma and 920 Ma, with a few older grains having formed between 1000–2549 Ma. One metasedimentary rock sample of the Wuguan Complex has a similar age spectrum as that of the Liuling Group, which shows the main age peak at 440 Ma and two subordinate peaks at 786 and 927 Ma, indicating all detrital zircon age results have the same source area. Geochemical analyses suggest that the sedimentary rocks of the Liuling Group and part of the Wuguan Complex were deposited in the tectonic setting of the continental island arc (CIA), while the geochemical characteristics of the other group of sedimentary rocks of the Wuguan Complex indicate the mixing of basic rock sources. The protolith of garnet amphibolite and hornblende schist, which were collected from the Wuguan Complex, were classified as andesite and basalt, with the nature of arc andesite and oceanic island basalt, respectively. In combination with regional data, we suggest that the Liuling Group and the Wuguan Complex were deposited in a fore-arc basin. Additionally, the Wuguan Complex was subsequently incorporated into the tectonic mélange by the northward subduction of the Paleo-Qinling Ocean. Zircons from the subduction-related metamorphic igneous rocks in the Wuguan Complex yielded a weighted mean age of 365 ± 19 Ma, indicating that the Paleo-Qinling Ocean between the SQT and NQT was still subducted at the end of Devonian. [ABSTRACT FROM AUTHOR]

The tectonic evolution of the Qinling Orogenic Belt in the Late Paleozoic has long been controversial, especially due to the limitation of the Mianlue Ocean subduction time. Basin formation and sedimentary development in the southern North China Block are closely related to the tectonic evolution of the Qinling Orogenic Belt, which is an effective entry point to study basin–mountain interaction. We present new detrital zircon U–Pb data from the Shihezi Formation in the Luonan area in the southern margin of the North China Block. The results show that the bottom sample has two major peaks at 288 Ma and 448 Ma, with weak peaks at 908, 1912 Ma and 2420 Ma. The top sample has one major peak at 297 Ma, with weak peaks at 1933 Ma and 2522 Ma. Combined with the published paleocurrent data and lithofacies paleogeography, the sediments of the bottom sample were sourced from the North Qinling Belt, Inner Mongolia Palaeo-Uplift and the basement of the North China Block. The top sample originated mainly from the Inner Mongolia Palaeo-Uplift and the basement of the North China Block. Comparing the obtained zircon U-Pb ages with the published relevant data in the North China Block, it is found that the provenance area shifted from the Qinling Orogenic Belt to the Inner Mongolia Paleo-Uplift in the Late Carboniferous–Permian, and the Qinling Orogenic Belt could hardly provide provenance for the southern North China Block in the Middle Permian. The uplift of the Qinling Orogenic Belt in the Late Carboniferous may be the continuation of Caledonian orogeny in the Early Paleozoic, whereas the uplift of the Inner Mongolia Palaeo-Uplift is related to the tectonic evolution of the Central Asian Orogenic Belt during the Late Paleozoic. This tectonic transformation occurred when the Qinling Orogenic Belt no longer supplied sediments to the southern North China Block in the Middle Permian, and the Mianlue Ocean subduction did not occur until at least the Late Permian. [ABSTRACT FROM AUTHOR]

Magmatic rocks, deformed structures, and tin–polymetallic deposits are widely distributed in the western Jiangnan Orogenic Belt (JOB) of northern Guangxi Province, China. Magmatism and mineralization are believed to have occurred in the Neoproterozoic stage. Herein, we report the zircon U–Pb dating results of investigations on the Ping'an Pb–Zn–Cu polymetallic veins hosted in gabbro near Ping'an Village. Zircon U–Pb dating of the host gabbro yielded ages of 853.0 ± 7.8, 837.7 ± 7.2, and 450.4 ± 6.7 Ma. The younger age represents the emplacement of gabbros, whereas the older Neoproterozoic age reflects inherited zircons from the wall rocks or source regions. The formation of gabbros (Caledonian) is related to the subduction and collisions of microplates in the western JOB, which are controlled by movements of the Yangtze and Cathaysian plates. We consider that the late Caledonian regional shearing in the western JOB resulted in the fracturing and faulting of rocks (Neoproterozoic and early Caledonian), which provided conduits for the flow of hydrothermal fluids and accommodation for the associated mineralization. Geochemistry investigations show that the Caledonian basic magmatic activity provided a certain material source for the final mineralization. We propose that the tin–polymetallic deposits in the northern Guangx Province, and Neoproterozoic cassiterite crystallization, were subjected to Caledonian shear crushing and hydrothermal transformation with copper, lead, zinc, and other metal elements based on our comprehensive analysis, providing a new ideology for understanding the geology and mineralization in this area. [ABSTRACT FROM AUTHOR]

The Tianshui-Sunjiaxia area is located in the connection zone of West Qinling Orogen and North Qilian Orogen, which could provide great insights into the amalgamation processes between the northern and southern blocks of China. Three subduction- and rift-related rocks gneissic granite from North Qilian arc-interarc belt (NQAI) granite and metabasalt from North Qinling back-arc basin (NQBA) are distinguished across the connection zone. The gneissic granite was generated by melts from older crustal materials of Longshan Group with the addition of a relatively juvenile basaltic source from the lower crust during the collision process. The Liwanxincun metabasalt reflects the mixing of the partial melting of the shallow asthenospheric mantle and the metasomatized mantle in a back-arc extension setting. The LA-ICP-MS zircon U-Pb dating of gneissic granite (068, 069) yields crystallization ages of 457.0 ± 1.6 Ma and 445.9 ± 2.1 Ma. The study area is divided into six tectonic units in Early Paleozoic time involving NQAI (Yanjiadian-Xinjie) continental arc, interarc rift basin (Maojiamo-Xiwali), continental arc (Chenjiahe-Wangjiacha); NQBA back-arc rift basin (Huluhe-Hongtubao), island arc and ophiolitic melange belt (North Qinling-Shangdan). A tectonic model is proposed in which the NQAI continental arc (Yanjiadian-Xinjie) might represent the early period of subduction of North Qilian Ocean (NQO) and the interarc rift is the product of the extension triggered by southward subduction of NQO. The ongoing subduction of NQO then leads to the formation of Chenjiahe-Wangjiacha continental arc, as well as the Hongtubao back-arc spreading ridge in NQBA back-arc basin (Huluhe). The tectonic evolution of the connection zone is closely associated with the closure of the North Qilian Ocean and North Qinling-Shangdan Ocean in the context of the convergence process of micro-continental blocks, including North China block, Longshan group and North Qinling Terrane. [ABSTRACT FROM AUTHOR]

The eastern Tiklik belt is mainly composed of meta-sedimentary rocks of the Ailiankate and Sailajiazitage Groups that were previously interpreted as Palaeoproterozoic, Mesoproterozic and Neoproterozoic stratigraphic units, which are part of the Tarim Precambrian basement. Our new detrital (U-Pb) zircon ages yield a dominant single peak with a major range between ca. 700 Ma and 800 Ma for meta-sedimentary rocks from both the Ailiankate and Sailajiazitage Groups, which demonstrates that they were mainly derived from an independent Neoproterozoic terrane. There are several ages of 444–659 Ma, of which, the youngest has an age of 444 ± 6 Ma, indicating that the time of deposition of the meta-sedimentary rocks could have been in the Early Silurian. The porphyritic granite sample has a weighted mean crystallization age of 442 ± 2 Ma. The adakite-like geochemical characteristics of the porphytitic granite suggest derivation from the melting of the oceanic slab and formation in a subduction, arc-related tectonic setting. After integration with relevant published data, our work suggests that the Ailiankate and Sailajiazitage Groups belong to a tectonic mosaic that contains Middle Neoproterozoic extensional and Paleozoic accretionary and collisional complexes, rather than the Paleoproterozoic or Mesoproterozoic basement, as previously regarded. We propose a new tectonic model for the eastern Tiklik belt that started with a Middle Neoproterozoic extension and ended with Paleozoic continuous accretion and collision in a Paleo-Tethys archipelago, which contributed to the considerable continental growth of the southern Tarim Block. [ABSTRACT FROM AUTHOR]