Evaporites are widely distributed within continental “red beds” in the Lanping–Simao Basin, west Yunnan, China. Sr (Strontium), S (Sulfur), and O (Oxygen) isotope compositions have been measured on 54 sulfate or/and sulfate-bearing samples collected from Lanping, Nuodeng, Jinggu, Mengyejing, Baozang throughout the Lanping–Simao Basin. The ⁸⁷Sr/⁸⁶Sr ratios of all samples (0.708081 to 0.710049) are higher than those of contemporaneous seawater, indicating a significant continental contribution to the drainage basin. Sulfates in the Lanping Basin have higher ⁸⁷Sr/⁸⁶Sr ratios (0.709406 to 0.710049) than those (0.708081 to 0.709548) in the Simao Basin. Nevertheless, the δ³⁴S values of gypsums (13.4‰ to 17.6‰) in Lanping and Baozang fall within the range of Cretaceous seawater. Gypsums from a single section in Baozang have trends of decreasing δ³⁴S values and increasing ⁸⁷Sr/⁸⁶Sr ratios from base to top, indicating continental input played an increasingly significant role with the evaporation of brines. High δ³⁴S values (20.5‰ to 20.7‰) of celestites in Lanping are probably caused by bacterial sulfate reduction (BSR) process in which ³⁴S were enriched in residual sulfates and/or recycling of Triassic evaporites. The reduced δ³⁴S values of gypsums (9.5‰ to 10.4‰) in Nuodeng could have been caused by oxidation of sulfides weathered from Jinding Pb-Zn deposit. The complex O isotope compositions indicate that sulfates in the Lanping–Simao Basin had undergone sulfate reduction, re-oxidation, reservoir effects, etc. In conclusion, the formation of continental evaporites was likely derived from seawater due to marine transgression during the Cretaceous period. Meanwhile, non-marine inflows have contributed to the basin significantly.

Middle Triassic paleogeography is essential for the paleoclimate change and ecosystem recovery after the end-Permian mass extinction, but is highly debated in the Paleo-Tethys Ocean and North China Craton, eastern Pangaea. Here we report a detailed provenance fingerprinting dataset from Middle Triassic sediments across the North China Craton, Qinling and Songpan-Ganzi and identify the paleo-uplift in the northern North China Craton as a primary sediment source. We propose that a Middle Triassic transcontinental drainage system flowed from the northern North China Craton through the central Qinling into the eastern Paleo-Tethys Ocean along the gradually descending landform, challenging the suggestion that the North China Craton was a great endorheic basin. The finding of this study will provide a better understanding of Middle Triassic physiography and paleogeography of the North China Craton. Such heterogeneous paleotopography and transcontinental drainage played a critical role in the marine-terrestrial ecosystems of the eastern Pangaea.

Coal will continue to be the main energy source in China for the immediate future, although the environmental pollution and ecological impacts of each stage in the full life cycle of coal mining, transportation, and combustion generate large quantities of external costs. The Late Permian coals in southwestern (SW) China usually contain high amounts of fluorine (F), arsenic (As), and ash, which together with high-F clays cause abnormally high levels of endemic fluorosis, As poisoning, and lung cancer in areas where coal is mined and burned. In this paper, we estimate the external costs of the life cycle of coal. The results show that the externalities of coal in SW China are estimated at USD 73.5 billion or 284.3 USD/t, which would have accounted for 6.5 % of the provincial GDP in this area in 2018. The external cost of human health accounts for 87.2% of the total external costs, of which endemic skeletal fluorosis diseases and related lung cancers have the most important impact. Our study provides a more precise estimate of externalities compared with its counterparts in other provinces in China. Therefore, several policy recommendations would be proposed to internalize the external cost.

The early uplift of the Tibetan Plateau (TP) had a profound influence on the paleoenvironment and paleoclimate. However, we still have little information about the link between the paleoclimatic changes and flora ecosystem caused by the uplift. The Eocene fluvial-lacustrine sequences in the Gonjo Basin, eastern TP, provide excellent archives of the paleoecological and paleoclimatic responses to the surface uplift of the TP. In this study, we investigated a section of the middle Eocene Ranmugou Formation (47.8–>44 Ma) and used the sporomorphs assemblages, sedimentology, and geochemistry of the evaporites to reconstruct the paleoclimate and paleovegetation. The palynological assemblages and coexistence analysis reveal that the middle Eocene ecosystem in the Gonjo Basin was dominated by warm and humid temperate deciduous broad-leaved forests. The ⁸⁷Sr/⁸⁶Sr ratios (0.709942–0.710062) of all of the gypsum samples are higher than those of contemporaneous seawater, while the δ³⁴S values (10.3–11.0%) are much lower, indicating a lacustrine environment. Combined with published palynological and paleoelevation data for eastern Tibetan lacustrine basins, we infer that the paleoenvironment changed from warm and humid deciduous broad-leaved forests during 47.8–>44 Ma, to cool and arid temperate forest during 44–40 Ma in the Gonjo Basin, and to arid and cool steppe-desert vegetation in the late Eocene Nangqian Basin. The changes in the paleoclimate and vegetation were primarily driven by the surface uplift of the Central Watershed Mountain, the high topography of which blocked the moisture from the Asian Eocene monsoon.