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• A "porphyroclast" system occurred in the Tuwu area in the late Early Permian. • The dextral shear event within the Kangguer Shear Zone was initiated at ca. 278 Ma. • The event provides constraints to the intracontinental convergence of the East Tianshan. The Kangguer Shear Zone, located in the East Tianshan, is one of the key faults for understanding the final amalgamation processes of the southwestern margin of the Central Asian Orogenic Belt. Magmatism was active in the Tuwu area of the Kangguer Shear Zone during the late Early Permian. LA–ICP–MS U–Pb dating analyses of the magmatic zircons from three monzogranite plutons, a felsic dyke, and a diorite dyke show ages of 286.9±0.78, 282.8±0.62, 281.7±0.89, 278.0±0.61, and 278.1±1.2 Ma, respectively. Detailed field and microscopic observations reveal that these intrusions form a "porphyroclast" system, and this area has undergone ductile dextral strike-slip deformation, with foliations dipping steeply to the south and subhorizontal stretching lineations trending to the east. Further structural analysis indicates that the three monzogranite plutons intruded into the Kangguer Shear Zone and cooled into rigid bodies before regional dextral strike-slip deformation, which limited the deformation that occurred after 282 Ma. The felsic dykes exhibit synkinematic characteristics, and the diorite dyke may have intruded before or at the same time as dextral strike-slip deformation, implying that regional dextral shear was initiated at ca. 278 Ma. These data, combined with previous studies, suggest that the initiation of dextral shear in the Kangguer Shear Zone occurred after the closure of the Kangguer Ocean and was the result of regional nearly N–S compression caused by the convergence of the Tarim Craton and plates north of the Kangguer Shear Zone. [ABSTRACT FROM AUTHOR]

Model for the tectonic evolution of the SCTSZ within the Kawabulake area, showing the SCTSZ within the Kawabulake area was involved in two ductile deformation events (three stages) during the late Paleozoic. The D1 event (400–290 Ma) was caused by the clockwise rotation of the Tarim Craton and the oblique subduction of the South Tianshan Ocean crust beneath the CTB. The early stage of D2 (ca. 290 Ma) was associated with the oblique collision between the Tarim Craton and the CTB. The late stage of D2 (276–270Ma) records the convergence of the Tarim Craton and plates north of the CTB. 1 represents Kangguer–Huangshan Shear Zone that occurs along the North Tianshan Ocean; 2 represents North Central Tianshan Shear Zone that separates the CTB and the North Tianshan Belt; 3 represents SCTSZ that separates the CTB and the South Tianshan Belt; 4 represents Xingeer Shear Zone that separates the Tarim Craton and the South Tianshan Belt; CTB is the abbreviation for Central Tianshan Block; YB is the abbreviation for Yili Block; KO is the abbreviation for Kazakhstan Orocline; SCTSZ is the abbreviation for South Central Tianshan Shear Zone. [Display omitted] • The Kawabulake Shear Zone records two events of ductile deformation (D1 and D2). • The timing of D1 deformation is constrained in the range of 400–290 Ma. • The early stage of D2 and the late stage of D2 occurred at ca. 290 and 276–270 Ma, respectively. • The deformation events provide constraints to the amalgamation of the SW CAOB. The South Central Tianshan Shear Zone occurs along the southern margin of the Central Tianshan Block (CTB), NW China. This shear zone contains important information about the history of the amalgamation of various plates in the southwestern margin of the Central Asian Orogenic Belt. This study focuses on the deformation of the South Central Tianshan Shear Zone within the Kawabulake area in East Tianshan and provides insights into the late Paleozoic tectonic history of this region. Field observations indicate that the shear zone records at least two ductile deformation events (D1 and D2), where D1 is a sinistral strike-slip deformation event and D2 is dextral strike-slip. The shear zone contains four giant tectonic lenses that were formed during the D2 event. Microstructures and quartz crystallographic preferred orientation patterns indicate that D1 and D2 both occurred under low temperature conditions. We constrained the timing of deformation using mica 40Ar/39Ar and zircon U–Pb approaches. The timing of D1 deformation is constrained in the range of 400–290 Ma and the early and late stages of D2 deformation occurred at ca. 290 and 276–270 Ma, respectively. Regional comparisons indicate that D1 resulted from the clockwise rotation of the Tarim Craton and the oblique subduction of the South Tianshan Ocean crust beneath the CTB, the early stage of D2 was the result of the oblique collision between the Tarim Craton and the CTB, and the late stage of D2 records the convergence of the Tarim Craton and plates north of the CTB. [ABSTRACT FROM AUTHOR]

Abstract: The Dingshan area located in the northern part of the Junggar Basin of northwestern China is a significant prospect area for sandstone-type uranium deposits in China, where mainly Cenozoic rocks were deposited. The Cenozoic strata can be divided into four units according to the prior data and our own field observation. Sedimentary studies indicate that most Cenozoic strata were deposited under a hot and arid climate in a continental environment. The sedimentary facies are alluvial-fan, meandering-fluvial, and fluvio-lacustrine. Field investigation and interpretation of satellite images suggest that Cenozoic tectonics in the area is characterized by reactivation of early deep-seated thrusts, resulting in extensional fractures and formation of many small depressions in the shallow crustal level. Measurement of joint orientations suggests that regional shortening direction trends in north–south in the middle Pleistocene as indicated by the ESR (Electronic Spin Resonance) age of 0.1–0.4Ma obtained from fault gouge and gypsum deposits. A four-stage sedimentation-tectonic evolution model of the northern Junggar Basin during the Late Cenozoic can be established based on reconstruction of sedimentary filling processes and Cenozoic tectonic movements. We suggest that landform evolution and groundwater movement are controlled by active tectonics, indicating that Late Cenozoic tectonic activities may also play important roles in the formation of sandstone-type uranium deposits. Therefore, a new metallogenic model for sandstone-type uranium deposits is proposed. [ABSTRACT FROM AUTHOR]