molar ratio of benzene to MCB produced was a function of the substrate isomer and ranged from β (0.77 ± 0.15), α (0.55 ± 0.09), γ (0.13 ± 0.02), to δ (0.06 ± 0.02) in accordance with pathway predictions based on prevalence of antiperiplanar geometry. Data from 16S rRNA gene amplicon sequencing and quantitative PCR Pelobacter Dehalobacter revealed significant increases in the absolute abundances of and , most notably in the α - HCH and δ -HCH cultures. Cultivation with a different HCH isomer resulted in distinct bacterial communities, but similar archaeal communities. This study provides the first direct comparison of shifts in anaerobic microbial communities induced by the dechlorination of distinct HCH isomers. It also uncovers candidate microorganisms responsi ble for the dechlorination of α - , β - , γ - , and δ -HCH, a key step toward better understanding and monitoring of natural attenuation processes and improving bioremediation technologies for HCH-contaminated sites.

Qiu, Y., Wang, X.-L., Liu, X., Cao, J., Liu, Y.-F., Xi, B.-B., Gao, W.-L., 2020. In situ Raman spectroscopic quantification of CH - CO mixture: application to fluid inclusions hosted in quartz veins from the Longmaxi 4 2 Formation shales in Sichuan Basin, southwestern China. Petroleum Science 17, 23 - 35.

https://doi.org/10.1007/s12182-019-00395-z We re-evaluate the Raman spectroscopic quantification of the molar ratio and pressure for CH - CO mixtures. 4 2 Firstly, the Raman quantification factors of CH and CO increase with rising pressure at room temperature, 4 2 indicating that Raman quantification of CH /CO molar ratio can be applied to those fluid inclusions (FIs) with 4 2 high internal pressure (i.e., > 15 MPa). Secondly, the v (CH ) peak position shifts to lower wavenumber with 1 4 increasing pressure at constant temperature, confirming that the v (CH ) peak position can be used to calculate 1 4 the fluid pressure. However, this method should be carefully calibrated before applying to FI analyses because large discrepancies exist among the reported v (CH )-P curves, especially in the high-pressure range. These 1 4 calibrations are applied to CH -rich FIs in quartz veins of the Silurian Longmaxi black shales in southern 4 Sichuan Basin. The vapor phases of these FIs are mainly composed of CH and minor CO , with CO molar 4 2 2 fractions from 4.4% to 7.4%. The pressure of single-phase gas FI ranges from 103.65 to 128.35 MPa at room temperature, which is higher than previously reported. Thermodynamic calculations supported the presence of extremely high-pressure CH -saturated fluid (218.03 - 256.82 MPa at 200 °C), which may be responsible for the 4 expulsion of CH to adjacent reservoirs. 4

Qiu, Z., Lu, B., Chen, Z., Zhang, R., Dong, D., Wang, H., Qiu, J., 2019. Discussion of the relationship between volcanic ash layers and organic enrichment of black shale: A case study of the Wufeng-Long-maxi gas shales in the Sichuan Basin. Acta Sedimentologica Sinica 37, 1296-1308.

http://www.cjxb.ac.cn/EN/abstract/abstract4066.shtml Previous studies have shown that the deposition of volcanic ash from modern volcanic activity into seawater can improve marine surface productivity,promote the flourishing of plankton,and facilitate the formation and enrichment of organic matter. However,there are few studies on the relationship between volcanic ash deposition and organic matter enrichment in geological history,which has always been controversial. A large number of volcanic ash layers developed in the gas shales of the Wufeng-Longmaxi Formation during the Ordovician-Silurian transition in South China,providing a typical strata system for this research. Total organic carbon(TOC) content,paleo-productivity, and redox conditions of the shale horizons, including volcanic ash layers and no volcanic ash layers, were comparatively analyzed. The results show that the volcanic ash deposition during the Ordovician-Silurian transition had a relatively weak effect on marine productivity and did not significantly promote the accumulation of organic matter. The redox condition has a close relationship with TOC content,suggesting it could be the main controlling factor. The influence of volcanic activity on the sedimentary environment is a very complicated process. Therefore,in the future, comprehensive studies with higher resolution(such as centimeter-scale and millimeter-scale) should be carried out by using geological,geochemical,and other testing methods to finely analyze the impact of volcanic activity on the formation and enrichment of organic matter. Sediments related to volcanic activity are one of the research targets of unconventional petroleum sedimentology,and the determination of the relationship between them and organic enrichment in shale would have an important role in the exploration and development of unconventional petroleum,such as shale oil and gas.