Comparison of γ-ray spectrometry and ICP-MS methods for measuring radioactive heat-producing elements of rocks: a case study on borehole samples from the Sichuan Basin, China

We compared the consistency of γ-ray spectrometry and inductively coupled plasma mass spectrometry by analyzing measurement results of the radioactive heat-producing elements U, Th, and K from borehole samples. This analysis was based on 49 samples obtained from mudstone, siltstone, and carbonate rock, and 11 of the 15 control groups showed great consistency. The radioactive heat production (RHP) of carbonate rocks was relatively low (0.23–0.63 µW m−3) and was mainly contributed by U. Mudstone and siltstone have higher RHPs, which was 1.73 ± 0.46 and 2.04 ± 0.49 µW m−3, respectively

Constraining the denudation process in the eastern Sichuan Basin, China using low-temperature thermochronology and vitrinite reflectance data

The temperature history of samples and maximum palaeogeothermal profiles of boreholes were reconstructed based on low‐temperature thermochronology and vitrinite reflectance data, and the results provide limits for the timescale and amount of uplift–denudation of the eastern Sichuan Basin. The thermal history showed that the uplifting and cooling of eastern Sichuan Basin began around the Late Cretaceous (approximately 100–80 Ma). The region had experienced a continuous cooling process from the Late Cretaceous until the present, with the geothermal gradient decreasing from 32–36 °C/km to 20–23 °C/km. The amount of denudation at the Puguang region in north‐eastern Sichuan was approximately 2.3 km, whereas that at south‐eastern Sichuan was 1.9 km, and the erosion thickness in the eastern Sichuan fold belt that was revealed via the field samples is 2.3 ± 0.3–2.6 ± 0.3 km. The north‐eastern Sichuan experienced sustained cooling with inconspicuous fluctuations, whereas the thrust belt and the south‐eastern Sichuan Basin presented 2–4 stages with different cooling rates. It may indicate that the eastern Sichuan fold belt experienced a complex structural evolution, characterized by episodic upliftings and deformations since Late Cretaceous, while a different and gentle deformation took place in the northeastern Sichuan Basin

Meso-Cenozoic Exhumation of the Linqing Sub-Basin, Bohai Bay Basin: Implications for Cratonic Destruction

The relationship between the tectonic event of the Linqing Sub-basin and the destruction of the North China Craton (NCC) is an important factor to consider when studying geodynamic mechanisms in eastern China. In the current study, we present a low-temperature apatite thermochronological analysis of 14 samples to study the tectonic event of the Linqing Sub-basin. Our data showed that the apatite fission track (AFT) ages were in the range of 53.5–124.4 Ma, and the average track lengths were 8.00–11.24 μm. The grain ages showed that 10 samples had mixed ages and were characterized by discordant distribution. The minimum ages decomposed from AFT ages mainly ranged from 105.3 to 40.8 Ma. We identified a break-in-slope from the depth-minimum age profile, which was related to the Meso-Cenozoic tectonic event. The AFT age data could be decomposed into three age groups, namely, P3 (394.8–215.7 Ma), P2 (124.6–83.4 Ma), and P1 (70.7–40.8 Ma), indicating three significant tectonic events in the NCC. P3 is related to the uplift of the NCC at 445.0–315.0 Ma and deformation and magmatism at 320.0–200.0 Ma. P2 corresponds to the Mesozoic tectonic activities, such as the closure of the Mongol–Okhotsk Ocean, the turning of the Izanagi plate and mantle convection. P1 mainly corresponds to the Izanagi–Pacific ridge, the closure of the Tethys Ocean, and the rotation of the Philippine Sea plate in the Cenozoic. Our study provides evidence for the destruction of the NCC, and has significance for the understanding of the deep mechanism

Meso-Cenozoic Exhumation of the Linqing Sub-Basin, Bohai Bay Basin: Implications for Cratonic Destruction

The relationship between the tectonic event of the Linqing Sub-basin and the destruction of the North China Craton (NCC) is an important factor to consider when studying geodynamic mechanisms in eastern China. In the current study, we present a low-temperature apatite thermochronological analysis of 14 samples to study the tectonic event of the Linqing Sub-basin. Our data showed that the apatite fission track (AFT) ages were in the range of 53.5–124.4 Ma, and the average track lengths were 8.00–11.24 μm. The grain ages showed that 10 samples had mixed ages and were characterized by discordant distribution. The minimum ages decomposed from AFT ages mainly ranged from 105.3 to 40.8 Ma. We identified a break-in-slope from the depth-minimum age profile, which was related to the Meso-Cenozoic tectonic event. The AFT age data could be decomposed into three age groups, namely, P3 (394.8–215.7 Ma), P2 (124.6–83.4 Ma), and P1 (70.7–40.8 Ma), indicating three significant tectonic events in the NCC. P3 is related to the uplift of the NCC at 445.0–315.0 Ma and deformation and magmatism at 320.0–200.0 Ma. P2 corresponds to the Mesozoic tectonic activities, such as the closure of the Mongol–Okhotsk Ocean, the turning of the Izanagi plate and mantle convection. P1 mainly corresponds to the Izanagi–Pacific ridge, the closure of the Tethys Ocean, and the rotation of the Philippine Sea plate in the Cenozoic. Our study provides evidence for the destruction of the NCC, and has significance for the understanding of the deep mechanism