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Meso-Neoproterozoic dolostone is abnormally well-developed in the platform areas in China, detailly, in the Mesoproterozoic Calymmian Wumishan Formation of North China Basin, Neoproterozoic Ediacaran Qigbulak Formation of Tarim Basin, and the Neoproterozoic Ediacaran Dengying Formation of Sichuan Basin. The outcrops and drilling cores from these basins show that these dolostones are mostly thick-bedded to massive, with mud-sized to silt-sized crystalline dolostone reaching 86%–97% of the total dolostone thickness. These dolostones basically suffered no secondary metasomatism, regardless of containing microorganisms (such as algae and bacteria) or not. The analyses of sedimentary palaeogeographic features indicate that: (1) the Meso-Neoproterozoic dolostone nearly covered the entire area basins, and was widely deposited in supratidal to intertidal zones, as well as in open platform environments; (2) the dolostone was subdivided according to the crystalline size, with the distribution controlled by geomorphology, i.e., the pure mud-sized crystalline dolostone developing in depression areas, whereas the grainy mud-sized crystalline dolostone or the mound stromatolitic mud-sized crystalline dolostone developing in uplift areas; (3) deep-water basins developed between the carbonate platforms, and the seismic profiles show that these basins were formed by syngenetic deep faults in the Meso-Neoproterozoic strata. These syngenetic faults increased Mg2+ concentration in the seawater by injecting rich-Mg2+-bearing hydrothermal fluids into the carbonate platforms. The analyses of geochemical and paleoclimatic indexes reveal that there is no obvious difference in carbon and oxygen isotope ratios between dolostones having different textures, with the ratios similar to those of the global seawater of the Meso-Neoproterozoic, indicating that the silt-sized crystalline dolostone has the same sedimentary origin as the mud-sized crystalline dolostone, i.e., the former is from authigenic recrystallization of the latter rather than secondary metasomatism. Therefore, whatever the crystalline sizes are, the dolostones are all originated from sedimentation. All the petrological, sedimentary and geochemical data suggest that the dolostones covering almost the whole Meso-Neoproterozoic typical platform areas of China are of relatively primary sedimentary origin. [ABSTRACT FROM AUTHOR]

Sichuan Province is rich in crop straw, yet little is known about its spatial distribution pattern, potential in replacing chemical fertilizer and mitigating nutrient loss. Based on the statistical data and literature review, the spatial distribution and potential of nutrient resources in crop straw for replacing chemical fertilizers was evaluated in this study. The nutrient loss with both crop incorporation and chemical fertilizer application were examined using a nutrient release coefficient method and compared. Results showed that Chengdu Plain, Northeast and South Sichuan produced more than 95% of the total straw nutrient resources during the period of 2016–2020. The potential of crop straw to substitute potassium (K), nitrogen (N) and phosphorus (P) fertilizer were K 2 O 33.08–285.95 kg hm−2, N 9.52–82.32 kg hm−2 and P 2 O 5 4.91–28.71 kg hm−2, respectively. If chemical fertilizer was substituted by all the available straw nutrient resources, N and P loss can be decreased by 55.12% and 65.84% in average in Sichuan Province. 343.93 t of N loss and 20.05 t of P loss can be reduced in plain areas, 122.88 t of N loss and 46.29 t of P loss can be reduced in mountainous and hilly areas, and 5.65 t of t N loss and 3.54 t of P loss can be reduced in plateau areas. It can be concluded that there were rich crop straw nutrient resources in Sichuan Province with obvious spatial variability, solid consideration should be put on to the proper use of crop straw nutrient resources, with the aim of chemical fertilizer reduction, nutrient loss reduction and sustainable development. [Display omitted] • Chengdu plain produced the most crop straw nutrient resources in Sichuan Province. • Rice was the main contributor of crop straw nutrient resources in Sichuan Province. • Crop straw was with considerable potential for replacing chemical fertilizers. • Sustainable nutrient loss can be reduced via straw replacing chemical fertilizers. [ABSTRACT FROM AUTHOR]

Assessing the impact of climate change is important for ecosystem conservation and plant recovery, especially in climate sensitive regions. Various studies suggested that the Köppen classification is an effective method to depict climate change. However, these studies were restricted to large scales or of limited accuracy due to uncertainties in climate model projections. In addition, the impact of elevation on the shift of climate zones, as compared with other factors, is less emphasized. To address these issues we compiled the Köppen Climate Classification (period 1961-2010) for the study area, Sichuan Province, China. The spatial resolution was selected as 1 km × 1 km. Sichuan Province may be characterized by 3 main climate classes and 10 subtypes. The east-west gradient of the climatic regimes in Sichuan is represented by the main climate classes, warm temperate climates (C), snow climates (D) and polar climates (E), at which the most abundant class is C. The most abundant subtype is snow climate with dry winter and cool summer (Dwc). Shifts in Köppen climate classes reflect the observed trend of increasing temperature. Finally, the elevation showed an obvious impact on the distribution and the change of climate classes in Sichuan Province. The shift of areas covered by Köppen climate classes increases with elevation. [ABSTRACT FROM AUTHOR]

The Bailongshan pegmatite deposit is a newly discovered super-large Li–Rb–(Be–Ta–Nb) rare-metal deposit in the West Kunlun orogenic belt, northwest China. Fifty-two rare-metal orebodies (50–1230 m long by 1.5–157 m wide) have been discovered by detailed field surveying, making up a metallogenic field that is larger than 8250 × 400 m. The deposit is estimated to have ore reserves of more than 5.06 million tonnes (t) Li 2 O, 160,020 t BeO, 316,200 t Rb 2 O, 40,060 t Nb 2 O 5 , and 10,750 t Ta 2 O 5. Pegmatite dikes are zoned around a granodiorite batholith, ranging from barren through orebodies rich in Be, Nb, Ta, Rb, and Li with increasing distance from the batholith, similar to the classical model of a zoned Li–Ce–Ta (LCT)-type pegmatite. LA–ICP–MS analyses of coltan and zircon yield 206Pb/238U ages of 208.1 Ma and 212.3 Ma, respectively, representing the emplacement ages of the pegmatites and granodiorite. These data indicate a temporal link between the emplacement of the granodiorite batholith and rare-metal mineralization in the pegmatites, and that the Bailongshan rare-metal pegmatites are temporospatially related to the granodiorite batholith. The Bailongshan pegmatites and other rare-metal pegmatite deposits in the West Kunlun orogenic belt likely make up a >600-km-long Li metallogenic belt, and further exploration for rare-metal pegmatites should be focused on the area adjacent to Late Triassic granitoid plutons in the belt. This belt likely extends to the East Kunlun and West Sichuan rare-metal belts, forming the >2000-km-long, Late Triassic West Kunlun–Songpan–Garzê rare-metal metallogenic belt. • The Bailongshan deposit is a newly discovered superlarge Li-Rb-(Be-Nb-Ta) pegmatite deposit. • The Bailongshan Li-rich pegmatites (ca. 208 Ma) is closely related to the granodiorite batholith. • Further exploration of Li-rich pegmatite should be around the Late Triassic granitoids. • We highlight a huge "West Kunlun–Songpan-Ganzê rare-metal pegmatite metallogenic belt" occurs. [ABSTRACT FROM AUTHOR]