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This paper attempts to review the environmental geochemical characteristics (re.: enriched elements) in coals of the Late Permian Xuanwei Formation of NW Yunnan, China, and gauge the possible existence of significant relationships with the incidence and distribution of lung cancer in the region. To achieve this goal, 27 samples were collected in this region; the mineralogical characteristics and major and trace elements were analysed; the Pb isotopic composition was traced; the contribution of the source rock was calculated; and principal component analysis (PCA) was carried out. Our current findings are summarized as follows: (1) the minerals are mainly quartz (silica), chamosite, calcite and kaolinite; (2) MnO, SiO2, V, Cr, Co, Ni, Cu, Cd and W are enriched; (3) the LREYs (La, Ce, Pr, Nd, Pm, Sm and Eu) and HREYs (Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y) have similar enrichment degrees, and the fractionation degree of HREYs is higher than that of LREYs; (4) the source distance restricts the Pb isotope composition; (5) MnO, V, Cr, Co, Ni, Cu and Cd are controlled by the Emeishan basalt; the origin of SiO2 (authigenic quartz) is unclear; (6) the lung cancer tissue characteristics, PCA, and toxicological characteristics of elements suggest that the main components of enriched elements probably come from V, Cr, Co, Ni and Cd, not SiO2. In conclusion, the carcinogenic elements V, Cr, Co, Ni and Cd may be related to lung cancer. Since our study is highly explorative, this result leaves many interesting aspects to be further studied. Thematic collection: This article is part of the Geochemical processes related to mined, milled, or natural metal deposits collection available at: https://www.lyellcollection.org/topic/collections/geochemical-processes-related-to-mined-milled-or-natural-metal-deposits Supplementary material: The coal mine and coal sample description, major, trace elements, and XRD results of coal as well as regional geological map are available at https://doi.org/10.6084/m9.figshare.c.6444476 [ABSTRACT FROM AUTHOR]

Analyses of fluid inclusion leachates from ore deposits show that Na/Br ratios are within the range of 75 - 358 and Cl/Br 67 - 394, respectively, and this variation trend coincides with the seawater evaporation trajectory on the basis of the Na/Br and Cl/Br ratios. The average Cl/Br and Na/Br ratios of mineralising fluids are 185 and 173 respectively, which are very close to the ratios (120 and 233) of the residual evaporated seawater past the point of halite precipitation. It is suggested that the original mineralizing brine was derived from highly evaporated seawater with a high salinity. However, the inclusion fluid's have absolute Na values of 69.9-2606.2 mmol kg-1 and Cl values of 106.7 - 1995.5 mmol kg-1. Most of the values are much less than those of seawater; Na, 485 mmol kg-1 and Cl, 566 mmol kg-1, respectively; the salinity measured from fluid inclusions of the deposits ranges from 2.47 wt% to 15.78 wt% NaCl equiv. The mineralizing brine has been diluted. The δ18O and δD values of ore-forming fluids vary from -8.21‰ to 9.51‰ and from -40.3‰ to -94.3‰ respectively. The δD values of meteoric water in this region varied from -80‰ to - 100‰ during the Jurassic. This evidenced that the ore-forming fluids are the mixture of seawater and meteoric water. Highly evaporated seawater was responsible for leaching and extracting Pb, Zn and Fe, and mixed with and diluted by descending meteoric water, which resulted in the formation of ores. [ABSTRACT FROM AUTHOR]