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The lateral distribution of the magnetic layer beneath the Tarim Craton and its environs was estimated from spectral analysis using the newest high-resolution aeromagnetic dataset of mainland China, which is enlarged by EMAG2. As a proxy, the Curie point depth (CPD) provides a comprehensive view of a crust-scale thermal regime, accounted for the depth at which magnetite becomes paramagnetic, and the correspondence of the CPD with the tectonic regime indicates that the CPD is useful for delineating the regional crustal thermal structure. Furthermore, lateral variations in CPD provide useful insights into the lithospheric thermal state of the Tarim Craton and its surrounding areas and can be related to ancient and active tectonics, such as geothermal activity, seismicity, and mineral-petroleum generation. In the Tarim interior, the NW domain covering the Bachu Uplift and its surrounding areas corresponds to the minimum magnetic CPD signature geometry of this area, which is most likely linked to the Permian Tarim plume-lithosphere interaction. In contrast, the other domains are characterized by large CPD values (up to 50 km), which are floored by a Precambrian basement without the Permian magmatism modification. Moreover, the estimated CPD values are consistent with surface heat flow measurements with an inverse correlation, which can assist in identifying the potential area for mineral deposits and hydrocarbon fields. Earthquakes are mostly concentrated in the gradient and transition zones of the Curie surface, suggesting that these abrupt variation domains in the crustal thermal structure act as a secondary mechanism for earthquake generation.

The property of the magnetic basement and the faults in the basement is significant for structural evolution, the Phanerozoic deposition, and oil resource exploration of the Tarim Basin. Based on the newly acquired aeromagnetic and industry seismic data, we mapped the distribution of basement faults by applying magnetic gradient-processing methods such as the horizontal gradient derivative, the first vertical derivative, the tilt derivative, and the upward continuation method. The dips of basement faults were confirmed and the susceptibilities of basement blocks were obtained by forward modeling of five profiles using the constraint of sedimentary strata depth and Moho topography. On the basis of comprehensive analysis of the magnetic anomalies, the distribution and inclination of basement faults, and susceptibilities differentiation obtained by forward modeling and field measurement, the property of the basement faults and their implication were discussed and interpreted. Our results show that the origin of the Central Highly Magnetic Anomaly Belt is highly magnetic Archean metamorphic rocks. The weakly magnetic Southeastern Domain and highly magnetic Central Tadong Domain assembled along the Tadong South Fault during the Paleoproterozoic. The Paleozoic Cherchen Fault is just an interior fault in the weakly magnetic Southeastern Domain although it presents a large vertical fault displacement. Considering the prominent variation of strikes of the Tadong North Fault system, and the moderately magnetic anomalies in the Northeastern Mangal Domain corresponding to the center of Neoproterozoic deposition, it is likely that the basement of the Northeastern Mangal Domain modified by the Neoproterozoic rifting could be originally the same as the basement of Central Highly Magnetic Anomaly Belt.

A Carboniferous trench-arc-basin system related to oceanic slab subduction has been thoroughly imaged by various geophysical probing approaches and proposed for the formation of West Junggar, Northwest China, located in the southwest of the Central Asian Orogenic Belt. However, debate on the origin of West Junggar still continues. Here, we present an integrated aeronautic magnetic–gravity observation to further identify the trench-arc-basin system and constrain the subduction mode. By deploying an integrated aerial magnetic–gravity survey consisting of 66,000 survey-line kilometers from August 3, 2015 to April 22, 2016, we determine the magnetic and gravitational anomaly across the study region by using geophysical potential-field processing. Our results reveal curial crust-scale variations in magnetic and gravitational structures beneath West Junggar and that a prominent Bouguer gravity high is located between the Darbut and Karamay–Urho faults, likely corresponding to a trapped oceanic slab. Notably, the Tacheng Basin is characterized by high-frequency magnetic signal and gravity highs, as well as the Carboniferous rifting–related sedimentary cover, which could be reasonably interpreted to be a back-arc basin. Integrated with these comprehensive geological and geophysical observations across West Junggar, the previous model of West Junggar trench-arc-basin system related to a fossil intra-oceanic subduction during the Late Paleozoic is further renewed.