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The impact of tectonics, volcanism and climate in controlling temporal and spatial variations in rift‐basin sedimentation is still poorly understood. Here, we tackle this issue by the analysis of mid‐Cretaceous sediments deposited in the Songliao Basin, northeastern China. We present new zircon U–Pb, apatite fission‐track and trace‐element data from the northeastern basin, which are discussed within the framework of the published geochronology dataset. Our results reveal a major provenance change from syn‐rift tectonic extension to post‐rift thermal subsidence at ~103 Ma. During the syn‐rift stage, the detrital inputs were dominantly from transverse rivers sourced from the surrounding mountains including graben shoulders and volcanoes. During the post‐rift stage and coeval thermal subsidence, the basin sedimentation was controlled by coexisting transverse and axial drainage systems sourced from uplifting regions in the south. We conclude that tectonics, not climate, exerted a major control in sediment provenance change in the mid‐Cretaceous Songliao Basin. [ABSTRACT FROM AUTHOR]

The Tianyu Cu‐Ni sulfide deposit occurs in the north margin of the Central Tianshan Arc in East Tianshan orogenic belt, Xinjiang, NW China. The intrusions consist of gabbro, peridotite, and olivine pyroxenite. The peridotite and pyroxenite are the main host rock for the Cu‐Ni ores. Rhenium and osmium isotopic analyses of Ni‐ and Cu‐bearing sulfide minerals from the deposit have been used to determine the source of osmium, and by inference, the sources of ore metals. Sulfide ore samples have Os and Re concentrations varying in the ranges 1.85 to 4.58 ppb and 93.56 to 146.00 ppb, respectively. An initial 187Os/188Os ratio ranges from 0.86 to 1.23 for the ores and the γOs values from 592 to 2227. Osmium isotopic data suggest that the Tianyu intrusion and associated Cu‐Ni mineralization has derived from crustal‐contaminated mantle melts. The intrusions early show island‐arc geochemical signatures, which indicate that the Hulu mafic–ultramafic intrusions, along with the Cu‐Ni deposit, formed as a result of subduction of oceanic crust in the Early Permian. [ABSTRACT FROM AUTHOR]

The atmospheric concentration of nitrous oxide (N2O) has increased by 23% since the pre‐industrial era, which substantially destructed the stratospheric ozone layer and changed the global climate. However, it remains uncertain about the reasons behind the increase and the spatiotemporal patterns of soil N2O emissions, a primary biogenic source. Here, we used an integrative land ecosystem model, Dynamic Land Ecosystem Model (DLEM), to quantify direct (i.e., emitted from local soil) and indirect (i.e., emissions related to local practices but occurring elsewhere) N2O emissions in the contiguous United States during 1900–2019. Newly developed geospatial data of land‐use history and crop‐specific agricultural management practices were used to force DLEM at a spatial resolution of 5 arc‐min by 5 arc‐min. The model simulation indicates that the U.S. soil N2O emissions totaled 0.97 ± 0.06 Tg N year−1 during the 2010s, with 94% and 6% from direct and indirect emissions, respectively. Hot spots of soil N2O emission are found in the US Corn Belt and Rice Belt. We find a threefold increase in total soil N2O emission in the United States since 1900, 74% of which is from agricultural soil emissions, increasing by 12 times from 0.04 Tg N year−1 in the 1900s to 0.51 Tg N year−1 in the 2010s. More than 90% of soil N2O emission increase in agricultural soils is attributed to human land‐use change and agricultural management practices, while increases in N deposition and climate warming are the dominant drivers for N2O emission increase from natural soils. Across the cropped acres, corn production stands out with a large amount of fertilizer consumption and high‐emission factors, responsible for nearly two‐thirds of direct agricultural soil N2O emission increase since 1900. Our study suggests a large N2O mitigation potential in cropland and the importance of exploring crop‐specific mitigation strategies and prioritizing management alternatives for targeted crop types. [ABSTRACT FROM AUTHOR]

A great number of magmatic Cu‐Ni deposits (including Kalatongke in Xinjiang and Hongqiling in Jilin) are distributed over a distance of almost 3000 km across the Tianshan‐Xingmeng Orogenic Belt, from Tianshan Mountains in Xinjiang in the west, to Jilin in eastern China in the east. These deposits were formed during a range of magmatic episodes from the Devonian to the Triassic. Significant magmatic Cu‐Ni‐Co‐PGE deposits were formed from the Devonian period in the Nalati arc (e.g. Jingbulake Cu‐Ni in Xinjiang), Carboniferous period in the Puerjin‐Ertai arc (e.g. Kalatongke Cu‐Ni‐Co‐PGE in Xinjiang), Carboniferous period in the Dananhu‐Touquan arc (e.g. Huangshandong, Xiangshan and Tulaergen in estern Tianshan, Xinjiang) to Triassic period in the Hulan arc (e.g. Hongqiling Cu‐Ni in Jilin). In addition to the overall tectonic, geologic and distribution of magmatic Cu‐Ni deposits in the Tianshan‐Xingmeng Orogenic Belt, the metallogenic setting, deposit geology and mineralization characteristics of each deposit mentioned above are summarized in this paper. Geochronologic data of Cu‐Ni deposits indicate that, from west to east, the metallogenic ages in the Tianshan‐Xingmeng Orogenic Belt changed with time, namely, from the Late Caledonian (∼440 Ma), through the Late Hercynian (300–265 Ma) to the Late Indosinian (225–200 Ma). Such variation could reflect a gradual scissor type closure of the paleo Asian ocean between the Siberia Craton and the North China Craton from west to east. [ABSTRACT FROM AUTHOR]