The sinistral Altyn Tagh strike‐slip fault demarcates the northern boundary of the Qinghai‐Tibetan Plateau; however, the significance and timing of activity along the fault are debated. Here new apatite and zircon (U‐Th)/He data are presented, revealing the exhumation history of the Altyn Tagh Mountains from crustal depths of ~2–7 km. Studies of rock samples from the Altun Shan region show that they were located close to the surface during the Early Cretaceous and remained so until about 40 Ma. Samples from the Subei and Dangjin Pass areas, on the other hand, record a period of rapid exhumation at 20 ± 2 Ma, and samples from the Qiemo area record a period of continuous exhumation between ~20 and 12 Ma at a rate of mm/year, plus a further rapid cooling event at 7–5.5 Ma. Thus, significantly more exhumation has occurred toward the southwestern section of the Altyn Tagh Fault Zone, indicating a decrease in tectonic uplift toward the northeast since the Miocene. During the late Miocene, the Tarim Block began to subduct beneath the northern Tibetan margin, resulting in rapid exhumation of the central section of the Altyn Tagh Fault Zone. In accordance with previous studies, the present results support a model of northward propagation and expansion of the Qinghai‐Tibetan Plateau during the Cenozoic.

It is difficult to date pyroclastic rocks, for almost all the dating methods, due to the multiple sources during their formation. ⁴⁰Ar/³⁹Ar incremental heating results on groundmass selected from the samples show that the age spectra are meaningless geologically. However, singe crystal total fusions of CO₂ lasing on the sanidine separates could yield rational ⁴⁰Ar/³⁹Ar results and distinguish their sources in this study. Timing on three formations of the Moshishan Group, after avoiding the exotic and altered grains by lasing on the single sanidine separate, was reported in this paper. The lowermost portion of the Chawan Formation gives an age of 113.7±0.3 Ma; the lower part of the Xishantou Formation was formed 116.4±0.4 Ma ago and the bottom of the Gaowu Formation took its shape at 118.4±0.4 Ma. These new ages are much younger than the previous ones, suggesting that these thick volcanic formations had been formed in very short durations.

The western North China Craton (NCC) entered a stage of craton thinning concentrated on its margin in the Cenozoic, but its Late‐Cretaceous conditions were previously deduced to be relatively quiescent. Therefore, whether the Late‐Cretaceous tectonic reactivation existed on the margin of this block is critical to understanding how the craton evolved into a thinned one. To investigate this possible margin reactivation in the Late Cretaceous, we apply zircon (U‐Th)/He thermochronology to Taibai Mountain on the southern margin of the western NCC. From an ∼3‐km‐high vertical profile with ages decreasing from 98 ± 5 Ma at the peak to 52 ± 7 Ma at the foot, the age‐elevation relationship suggests the rapid exhumation at ca. 78–71 Ma bracketed by two slow exhumation phases. This interpretation is confirmed by 1D half‐space modeling and QTQt inverse modeling, with the rapid exhumation stage having an exhumation rate of 0.1–0.6 km/Myr and a cooling rate of ∼10°C/Myr. Together with previously reported thermochronological data from the margin of the western NCC, the rapid exhumation at ca. 78–71 Ma implies a reactivated margin in the Late Cretaceous before widespread Cenozoic thinning of the craton margin. This Late‐Cretaceous reactivation likely resulted from WNW‐ESE extension expressed by thermo‐tectonic events, basin subsidence, and volcanism in East Asia. Excluding impacts from climate change, lithospheric delamination, and India subduction beneath Eurasia, we infer that the Late‐Cretaceous reactivation on the margin of the western NCC was driven by the far‐field effect of Izanagi Plate subduction beneath the Eurasian Plate during slab rollback of the subducted plate.

Tectonics and climate are the two competitive factors sculpturing landforms. Observations on the Earth surface are affected by signals from both tectonic and climatic agents. How to clarify these signals is a key issue. We categorize factors affecting mountain growth as horizontal (extension, compression, and transpression) and vertical (mantle upwelling and climate change) forces to evaluate the driving forces of accelerated exhumation in Taibai Mountain. Based on apatite (U-Th)/He thermochronology, we document two stages of accelerated exhumation at ca. 52-46 Ma and ca. 24-19 Ma from the age-elevation relationship, confirmed by 1D half-space modeling and QTQt inverse modeling. In the framework of paleostress, the two accelerated exhumation events occurred during transpressional periods in the early Eocene and late Oligocene-early Miocene in East China. These two events were triggered by the localized contractional deformation at the intersection of the North Qinling and Fengxian-Taibai faults: The opposite-direction shearing of these two faults was responsible for the former event with an unroofing magnitude of ~1 km; the same-direction shearing of the two faults resulted in the latter event with an unroofing magnitude of ~0.6 km. The far-field effects of both India-Eurasia collision and Pacific subduction drove the accelerated exhumation at ca. 52-46 Ma. The lateral extrusion of the Tibetan Plateau acted as the main driving force for the accelerated exhumation at ca. 24-19 Ma, which may have been slightly influenced by the intensified Asian summer monsoon in the early Miocene.

The Chang'e‐5 landing site provides an important window into the Moon's late Eratosthenian period of volcanism at ∼2 Ga. Clarifying the Moon's history of volcanic activity using radioisotopic dating assists investigations of the evolution of the lunar surface as well as the Moon's internal dynamics. Recent chronological investigations of Chang'e‐5 basalts produced ages spanning ∼100 Ma, thereby inhibiting interpretation of the duration of volcanism recorded in the returned samples. We used microcomputed tomography and Back‐Scatter Electron imaging to characterize the structure and morphology of nine Chang'e‐5 basalt clasts. Several basalt clasts lack shock features and are interpreted to have not been significantly thermally disturbed. ⁴⁰Ar/³⁹Ar incremental heating produced well defined plateaus for four sub‐split samples that give a weighted mean age of 2,021 ± 17 Ma (2σ). These are among the youngest mare basalts to be dated thus far by the ⁴⁰Ar/³⁹Ar method and, when combined with most of the published Pb‐Pb ages for Chang'e‐5 basalts, define a single episode of mare volcanism at ∼2,021 Ma.

Integrated ⁴⁰Ar/³⁹Ar and U-Pb geochronology, combined with microstructural analysis of Early Cretaceous volcanics from eastern China, challenge conventional interpretations of flat ⁴⁰Ar/³⁹Ar age spectra. K-feldspar sample JD-1K (122.12 ± 0.81 Ma) preserves magmatic sanidine characteristics (homogeneous composition, disordered monoclinic structure), while hydrothermally altered perthite JD-2K yields a flat plateau age of 99.83 ± 0.73 Ma (~20 Ma younger than coeval K-feldspar, biotite, and zircon samples). Microstructural analyses using energy dispersive spectroscopy (SEM−EDS), Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM) methods unequivocally demonstrate that the concordant ⁴⁰Ar/³⁹Ar age spectrum of sample JD-2K is a result of isotopic resetting during fluid-mediated recrystallization processes, rather than primary post-crystallization thermal stability. In step-heating experiments, contrasting argon release patterns correlate with microstructural heterogeneities. This study challenges the paradigm that flat ⁴⁰Ar/³⁹Ar spectra uniquely signify post-crystallization thermal histories, demonstrating that hydrothermal alteration can fully reset argon systems to produce misleadingly concordant ages. This study highlights the complexity of interpreting isotopic data in hydrothermally altered rocks, emphasizing the necessity of integrated petrological-geochemical analyses to differentiate primary magmatic signals from secondary overprints.