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In situ carbonate U-Pb dating is gaining popularity, and it has great potential for application in petroleum geology. However, the low U content (<10 µg/g) and high common Pb content of carbonate minerals, along with the uneven distribution of U and Pb and the lack of matrix-matched reference material make carbonate U-Pb dating inaccurate and less successful, which limits the widespread application in geosciences. This study evaluated the limitations of in situ carbonate U-Pb dating and proposed a method to rationally determine the laser ablation parameters of samples by improving the experimental approach based on the laser ablation sector field inductively coupled plasma mass spectrometry (LA-SF-ICP-MS). By setting a different spot size and laser frequency for the reference material and unknown samples in the same session based on the U content of the sample, the ablation craters of the reference material and unknown samples were given the same depth/width ratio, avoiding systematic offset caused by differences in down-hole element fractionation and reducing the consume of reference material. Depending on the heterogeneous distribution of U and Pb contents in carbonate minerals, the method of grid screening and setting ablation spots during screening were used to quickly select domains with high U and low common Pb, which improves the efficiency of setting laser spots and the success rate of dating, as well as reduces the experimental time and economic cost. The accuracy and success rate of carbonate U-Pb dating were effectively improved by improving the experimental method, and the technique was applied to two carbonate samples with low U and high common Pb contents that were difficult to date by traditional methods. The two samples are the saddle dolomite in the central Sichuan Basin and the calcite cement in the sandstone reservoir of the Cretaceous Qingshuihe Formation in the South Junggar Basin. The robust ages have been obtained, which constrains the timing of the diagenetic and hydrocarbon accumulation process in the studied area. [ABSTRACT FROM AUTHOR]

The detailed lithospheric structure of South China is the basis for the understanding of tectonic processes of eastern China. Specifically, two essential issues in the study of lithospheric structure are the thermal and compositional structures, which are usually derived from either geophysical or geochemical observations. However, inversions from single geophysical or geochemical datasets have certain limitations, making it necessary to develop joint inversions of geophysical, geochemical and petrological datasets. In this paper, through thermodynamic simulation and probabilistic inversion, we inverted multiple datasets including topography, geoid height, surface heat flow and surface wave dispersion curves for the 3D lithospheric thermal and compositional structure of South China. The results reveal a thin (< 100 km) and flat LAB beneath the South China Fold System Block and the lower Yangtze Craton. Also, we found that the lithospheric mantle is primarily composed of saturated peridotite, indicating that the ancient refractory lithospheric mantle has been replaced by new materials. The dominant dynamic mechanism for lithospheric thinning in eastern South China may be the flat subduction of ancient Pacific slab, while thermal erosion may have also played a significant role. In contrast, the LAB depth beneath the Sichuan Basin is much thicker (> 200 km), suggesting that the thick and cold craton lithospheric roots are retained. There may exist a discontinuous interface beneath the Sichuan Basin, with the saturated lower layer thicker than the refractory upper layer. As a result, the lithospheric mantle of the Sichuan Basin and surrounding regions is mainly composed of saturated and transitional peridotite. [ABSTRACT FROM AUTHOR]

Chinese Baijiu is a traditional distilled spirit that is consumed abundantly in China and around the world. Aging would dramatically increase the flavor of Baijiu, and famous Baijiu usually needs the long storage time for aging. Therefore, artificial aging that could accelerate the flavor improvement is in high demand. In this study, an electric-field treatment device was developed for the electric-field aging of the liquor. We used three types of strong-flavor crude Baijiu from different manufacturers in Sichuan as samples for electric-field aging. The total acids and esters, volatile flavor components, and sensory evaluation of the Baijiu samples before and after treatment were determined. It was found that the total acids and total esters of the Baijiu samples decreased and increased, respectively, with aging. The composition of volatile components changed after the aging treatment, and the volatile flavor components associated with the changes in the quality of Baijiu were analyzed. Combined with the sensory evaluation results, it was concluded that the quality of the treated Baijiu was significantly improved via electric-field aging. The result showed that electric-field aging can be an effective way to improve the flavor of Baijiu. • We developed a small-scale electric field treatment equipment for artificial aging of Baijiu. • The effect of this electric field treatment apparatus on the quality of three strong-flavor crude Baijiu was investigated. • Provide a new direction for artificial aging of Chinese Baijiu. [ABSTRACT FROM AUTHOR]

• Distribution of forest fire was concentrated in the southern region near the border. • There was an increasing trend of forest fire crossing national and provincial borders. • Forest fire policy is the main driver, followed by biophysics and human intervention. • Human interventions via policy significantly affected the forest fire occurrences. • Fire prevention publicity and education near the national border should be improved. Forest fire is a recurrent and serious problem which stirs major environmental, economic, and social concerns. Information on the temporal–spatial distribution of ignition probability and identifying the factors that drive the pattern of forest fire occurrences are the most challenging issues over the world. In this study, the spatial distribution and temporal variation in forest fire occurrence were examined by applying the Maximum Entropy (Maxent) algorithm. Redundancy analyses were used to determine the contributions of driving factors (forest fire policy, human interventions, and biophysical variables) to the forest fire occurrences. In addition, the strength of the relationship between the forest fire policy, human interventions, and biophysical variables and their direct and indirect effects on forest fire occurrences were determined using structural equation models (SEMs). Our results showed the Maxent model was suitable for predictive modeling of the distribution of forest fire occurrences in southwestern China. The predicted area of forest fire occurrences in southwestern China during 2000–2017 was 3.25 × 105 km2 which mostly concentrated in the southern region. There was an increasing trend of forest fire crossing national and provincial borders. According to the temporal pattern of forest fire occurrences, additional ignition probability areas including the central Yunnan and the eastern Sichuan were found in spring when compared to those in winter. Moreover, forest fire policy is the main driver underlying the ignition, followed by biophysical factors and human interventions. These should be considered as key elements in the design of forest fire prevention programmes. Although the explanatory power of driving factors varied, national border distance (NBD) and conductive index (CI) that represented effects of forest fire policy were constantly the key driving variables. In addition, there is heterogeneity among the biophysical factors. The meteorological factors significantly affected on ignition probability in different temporal scale, while the effects of topographic factors were smaller. Human interventions had no significant direct effect on ignition probability, while they via fire policy had a significant positive indirect effect on the probability of fire occurrence. The results suggest that we should strengthen the administrative capacities to prevent forest fires, and improve the fire prevention publicity and education on the residents living near the national border and/or in low population density areas to get higher awareness and compliance of forest fire policies for local residents. [ABSTRACT FROM AUTHOR]