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Carbon peaking and carbon neutrality will be important policies to constrain China's economic and social development in the future. Based on the theory of computable general equilibrium, CGE model of carbon emission was constructed in this paper to simulate the influence of different scenarios of carbon emission reduction on economic and social development. The major contribution is to subdivide the energy sector according to primary energy and secondary energy, and construct the macro SAM table and micro SAM table of 21 energy sectors in 2017 to quantitatively simulate the impact of carbon emission reduction policies on China's economy and society, and put forward some policy suggestions based on this. [ABSTRACT FROM AUTHOR]

The Permian–Triassic mass extinction was the largest biotic extinction event in the Phanerozoic and affected both marine and continental life. Marine Permian–Triassic transitional sequences can be correlated in many regions, but this has proved difficult for continental successions. A growing number of studies show that spinicaudatans are some of the most common fossils in continental strata and can be used as index fossils for continental stratigraphic division and correlation. Here we document the morphology and biostratigraphic significance of Euestheria gutta based on well‐preserved fossils from southwestern China. It shows strong intraspecific morphological variation, while the most important feature is the strongly convex larval valve and significant finely pitted to weakly reticulated ornamentation on the growth bands. Evidence from palaeobotany, charcoal, and organic carbon isotopes indicated that the continental mass extinction in southwestern China was marked by the catastrophic loss of tropical rainforest vegetation, enhanced wildfire and a negative carbon isotope excursion (CIE) during the P–Tr transition. Meanwhile, abundant E. gutta first appeared at the onset of the negative CIE and just above the horizon of the loss of macroflora. Based on the global geographic distribution of E. gutta and temporal correlation, we conclude that this species existed from the latest Permian to the earliest Triassic, and the occurrence of E. gutta could be used as an index fossil of the continental mass extinction interval or P–Tr transitional beds. [ABSTRACT FROM AUTHOR]

Recent time-series from sediment traps show abnormally high chlorophyll-a concentrations and primary productivity in the oligotrophic central South China Sea (SCS), especially during wintertime. Here we present new insights from compound-specific hydrogen isotopic analysis of leaf wax n-alkanes and Sr-Nd isotope compositions extracted from four basin-wide surface sediment transects. We find that the deepest surface sediments in the central basin contain the most depleted n-alkane hydrogen isotopes, suggesting inputs from higher latitude soils in northern China. This is supported by the Sr-Nd isotope compositions of the same surface sediments. We propose that aeolian dust is transported by the winter monsoon and might fertilize the phytoplankton bloom in the central SCS. This process may have been enhanced in ancient times when the winter monsoon was stronger, driving both vertical mixing and dust transport to the central basin. Plain Language Summary Recent studies observe abnormally high winter primary productivity and nitrate concentrations in the surface waters of the central South China Sea (SCS). However, this is a nutrient limited region of the ocean, so the drivers of this primary productivity are unclear. Here we analyze leaf wax carbon and hydrogen isotopes, and Sr-Nd isotopes, along four shallow-to-deep-water sediment transects to trace the sources of dust and organic matter in the sediments of the central basin. Our results suggest the central basin sediments receive significant terrestrial inputs of dust and nutrients from northern Asia via long-range aeolian transport during the winter monsoon. These results give new insights to terrestrial-marine connections and the carbon cycle of the SCS. This process may provide a new mechanism to understand the glacial-interglacial productivity changes in marginal seas. [ABSTRACT FROM AUTHOR]

Middle to Late Ordovician carbonates were collected in South China (Anhui Province) from the Kuniutan, Datianba, and Pagoda formations in the Dingxiang and Daling sections and analysed for high‐resolution carbon isotope chemostratigraphy. An increase by 0.4‰ in δ13Ccarb is observed in the upper part of the Kuniutan Formation (Eoplacognathus pseudoplanus Biozone), representing the rising limb of the Middle Darriwilian Isotopic Carbon Excursion (MDICE). In the upper part of the Datianba Formation, positive shifts of ca. 1‰ are recorded in the studied section which compare with the carbon shifts reported in North America and Baltoscandia. A pronounced positive δ13Ccarb excursion of ca. 1.5‰ from the lower part of the Pagoda Formation can be correlated with the global Guttenberg Isotopic Carbon Excursion (GICE). The documentation of three carbon isotope shifts in this study provides new evidence for changes in the global carbon cycle from Darriwilian to Early Katian which could have been influenced by changes in global climate and primary productivity. [ABSTRACT FROM AUTHOR]

Analysis of stable isotope composition is an important tool in research on plant physiological ecology. However, large‐scale patterns of leaf‐stable isotopes for aquatic macrophytes have received considerably less attention. In this study, we examined the spatial pattern of stable isotopes of carbon (δ13C) and nitrogen (δ15N) of macrophytes leaves collected across the arid zone of northwestern China (approximately 2.4 × 106 km2) and attempted to illustrate its relationship with environmental factors (i.e., temperature, precipitation, potential evapotranspiration, sediment total carbon and nitrogen). Our results showed that the mean values of the leaf δ13C and δ15N in the macrophytes sampled from the arid zone were −24.49‰ and 6.82‰, respectively, which were far less depleted than those measured of terrestrial plants. The order of averaged leaf δ13C from different life forms was as follows: submerged > floating‐leaved > emergent. Additionally, our studies indicated that the values of foliar δ13C values of all the aquatic macrophytes were only negatively associated with precipitation, but the foliar δ15N values were mainly associated with temperature, precipitation, and potential evapotranspiration. Therefore, we speculated that water‐relation factors are the leaf δ13C determinant of macrophytes in the arid zone of northwestern China, and the main factors affecting leaf δ15N values are the complex combination of water and energy factors. [ABSTRACT FROM AUTHOR]

The Dongpu Depression is one of the major petroliferous structures in the Bohai Bay Basin of eastern China. The Shahejie Formation is the key target unit for petroleum exploration in the Dongpu Depression. The current studies on this fossiliferous structure mainly focus on the northern depression, and the detailed study on the southern part of the depression is still scarce. To further study on the southeast subsag located in the southern part of this depression, we examined the geochemical characteristics and origin of petroleum using stable carbon isotopes, components of crude oil and natural gas, micro Fourier transform infrared spectroscopy (FT‐IS), gas chromatography (GC) and gas chromatography–mass spectrometry (GC–MS). Fluid inclusions and 1D model were employed to reconstruct the burial and thermal history and indicate the timing of hydrocarbon generation. Finally, the petroleum exploration in this region is guided based on the combination of geochemical results and geological setting. The result of geochemical characteristics of crude oils indicates the oil was from the combination of algal and terrestrial plants, deposited in reducing to sub‐oxic and fresh to marginally brackish environment. Furthermore, the oil in the northeastern part could be traced to the Haitongji subsag and has relatively lower thermal maturity than that in the central part. Stable carbon isotope data suggest that natural gas is a mixed oil‐type and coal‐type gas. The equation estimated indicates that natural gas in the northeast is mainly oil‐type gas, with an average ratio of 80.0%, whereas coal‐type gas is dominant in the central part (average percentage: 74.3%). Geochemical characteristics of hydrocarbon indicate that the Changyuan Fault was a migration pathway for the northeastern petroleum, whereas it gradually changed to be sealed towards the central part. [ABSTRACT FROM AUTHOR]

The richly fossiliferous succession of the Wulipo Formation in the Huangjiaba area near Meitan in northern Guizhou, SW China, represents one of the very rare records of shelly fauna across the Ordovician and Silurian transition worldwide. This area is therefore crucial for understanding the pattern and dynamics of the end‐Ordovician mass extinction (EOME). Historically, the Wulipo Formation was dated as middle Rhuddanian (early Silurian). However, its fauna shows a close affinity with Transitional Benthic Fauna 3 (TBF 3), now known to be confined within the late Hirnantian (latest Ordovician) in well‐constrained successions globally. Here we present for the first time, chemostratigraphic data from the Wulipo Formation which confirm the presence of the Hirnantian Isotope Carbon Excursion. A critical review of faunal evidence further indicates a late Hirnantian age for this formation, and thus the hitherto only known anomalous TBF 3 record documented from South China is convincingly redated. The important implication is that the substantial biotic recovery after the EOME commenced globally at the very beginning of the Silurian with an overall amelioration of physical conditions. The new findings also suggest a much wider distribution of postglacial warm‐water benthic faunas on the Yangtze Platform during the late Hirnantian than previously envisaged. [ABSTRACT FROM AUTHOR]

The Fukang Sag hosts prolific Jurassic lacustrine source rocks, which include the Badaowan (J1b), Sangonghe (J1s), and Xishanyao (J2x) formations in the Junggar Basin. Depositional conditions were reconstructed based on various major and trace element proxies for the East Fukang Sag during the Jurassic. The palaeowater depth in the sag was shallow and did not display a great change during the deposition of the J1b, J1s, and J2x formations, as indicated by lithological composition and the widespread ripple cross‐beddings. The oxic to dysoxic and fresh‐water conditions were postulated to prevail in the sag during the deposition of these source rocks, as revealed by concentrations of salinity‐ and redox‐sensitive trace elements [i.e., V/Cr, Ni/Co, (Cu+Mo)/Zn, Sr/Ba ratios, and Sr, Mn, Ga contents] derived from the source rocks. The seasonal salinity stratification superposed on preexisting thermal stratification led to the appearance of the chemocline in the J1b Formation. The palaeoclimate regime was humid and warm during the depositions of the J1b and the upper J1s formations, and warmer and drier during the deposition of the lower J1s Formation, but the palaeoclimate gradually became semi‐arid and semi‐cold during the deposition of the upper J2x Formation, as implied by various proxies (i.e., Sr/Cu ratio, C‐value, and CIA value). Despite the fact that the oxic to dysoxic conditions were not conducive for organic matter (OM) preservation, the significantly moderate‐high palaeoproductivity (suggested by, i.e., Ba content and Ba/Al ratio), which was promoted by a suitable supply of nutrient from terrestrial inputs in the shallow water was the controlling factorfor the OM accumulation on the margin of the sag, but the low OM concentration was controlled by the palaeoredox conditions in the central area, which was far from the OM input source [suggested by the relationship between total organic carbon content and stable carbon isotope composition of OM (δ13Corg)]. The analyses based on Rock‐Eval pyrolysis, maceral composition, C/N ratio of isolated kerogen, and δ13Corg value showing the OM was derived from terrestrial higher plants with C3 plants (type III kerogen) are consistent with the palaeoenvironmental analysis. [ABSTRACT FROM AUTHOR]

Eastern Shandong is one of the most economically important regions for ore‐producing sedimentary‐metamorphic graphite deposits in China. The Liugezhuang and Daliangzikou graphite deposits in the Pingdu–Laixi Graphite Belt are typical examples. The ores in the Liugezhuang deposit and Daliangzikou deposit are typically gneiss/granulite type and biotite granulite type, respectively. Graphite occurs as stratabound layers of slender flakes associated with biotite, clinopyroxene, and plagioclase and as slender flakes and disseminated grains associated with biotite and filling tiny fractures in mineral grains. The mineral associations indicate that the ore rocks can be classified into four metamorphic facies: (a) amphibolite granulite facies, Cpx (Hy) + Opx (Di) + Pl ± Hbl ± Qz; (b) amphibolite facies, Hbl + Pl + Cpx (Opm) + Ep + Bt + Ms + Qz ± Chl ± Mic; (c) high‐grade greenshist facies, Hbl + Pl + Ep + Bt + Chl + Qz ± Cpx; and (d) low‐grade greenshist facies, Ep + Chl + Pl + Bt + Ms + Chl + Qz + Rt. Study of the variation in graphite crystals and fixed carbon with increasing metamorphic grade suggests that more than one metamorphism process (graphitization) occurred during ore formation. Geochemical analysis indicates that the primary condition under which the Liugezhuang and Daliangzikou graphite deposits formed was a marine facies sedimentary environment of which the material source was terrestrial weathering detritus and compounds and also a participation of terrestrial material in the graphite deposits. Trace element data suggest that the sedimentary condition was from a reducing condition in the Liugezhuang graphite deposit to a weaker reducing condition in the Daliangzikou graphite deposit, whereas samples from a Jingshan Group stratum show multiple oxidation–reduction conditions but dominantly oxidation. Carbon isotope analysis indicates that the carbon source of the Liugezhuang graphite deposit was organic, whereas that of the Daliangzikou graphite deposit was mainly organic carbon but with some inorganic participation. [ABSTRACT FROM AUTHOR]

The Wangjiadashan Cu–Au deposit is a vein‐type deposit controlled by the secondary faults of the Wushan Fault zone in the Suizao area of Hubei Province. Three hydrothermal stages are identified, namely, (I) barren quartz stage, (II) the quartz‐sulphide stage, and (III) quartz‐carbonate stage. Six types of fluid inclusions occur in quartz: (a) liquid‐rich aqueous fluid inclusions (L + V), (b) vapour‐rich aqueous‐carbonic fluid inclusions (V + L), (c) water‐rich aqueous‐carbonic fluid inclusions (L + V + CO2), (d) CO2‐rich aqueous‐carbonic fluid inclusions (V + L + CO2), (e) pure carbonic fluid inclusions (pure CO2), and (f) daughter mineral‐bearing multiphase inclusions (S‐type) with three subclasses (S1, S2, and S3 subtype). Two types of fluid inclusions occur in calcite: (a) liquid‐rich aqueous fluid inclusions (L + V) and (b) pure carbonic fluid inclusions (pure CO2). The S‐type fluid inclusions include halite (NaCl), calcite (CaCO3), and chalcopyrite (CuFeS2). The fluid system is composed of CO2–NaCl–H2O. The homogenization temperatures of the three stages are 295°C to 390°C, 245°C to 280°C, and 200°C to 241°C, with salinities of 7.3–19.8 wt% NaCl equiv. (except for several high values of 33.8 to 44.3 wt% NaCl equiv.), 7.7–13.7 wt% NaCl equiv., and 5.6–10.1 wt% NaCl equiv., respectively. Fluid immiscibility occurred in stage I that accounts for the high‐salinity fluids, but the dominant ore precipitation occurred afterward during temperature drop. In situ sulphur isotope analysis indicates a δ34S value around 0 (+1.1% to +2.2%) for the chalcopyrite, suggesting that the sulphur likely derived from the deep‐seated magma. Pyrites show δ34S values from −0.5‰ to +6.5‰ in stage II, from +0.7‰ to +6.6‰ in country rock of marble, but significantly higher from +12.8‰ to +21.7‰ in country rock of greenschist. These results indicate the sulphur for pyrite in stage II likely derived from the mixing of deep‐seated magma and country rocks. From stages I to II, a slightly increase of δD (from −86‰ and −73‰ to −59‰ and −56‰) and a decrease of δ18O (from 8.9‰ and 7.1‰ to 1.3‰ and 3.4‰) indicate that an increasing involvement of meteoric water. The carbon isotopes of fluid inclusions CO2 in quartz of stage I (−11.0‰ to −13.0‰) indicate a major magmatic or metamorphic carbon source mixed with minor sedimentary sourced carbon, but a major organic carbon source (−32.0‰ to −35.0‰) for stage II fluids. In conclusion, the Wangjiadashan Cu–Au deposit belongs to the orogenic type. [ABSTRACT FROM AUTHOR]

The north‐eastern Ordos Basin in Central China has become an exploration target in recent years due to the potential of natural gas resources in the Upper Palaeozoic strata. In this study, by analysing the geochemical characteristics of the source rocks and the natural gas, the genesis of the Upper Palaeozoic natural gas was identified. In addition, the accumulation process was discussed by combining studies of hydrocarbon generation and burial/thermal history. The results reveal three sets of source rocks developed in the study area—Carboniferous Benxi (C2b), Permian Taiyuan (P1t), and Shanxi (P1s) formations—consisting of mudstones, carbonaceous mudstones, and coals. The source rocks contain abundant Type III organic matter and have entered mature to high‐mature stage, while source rocks in the south‐eastern part of the study area have entered the overmature stage due to the activity of Zijinshan magmatic rocks. The natural gas has a high content of methane (average 93.99%). The stable carbon isotope of methane (δ13C1) value (average −37.05‰) and that of ethane (δ13C2) value (average −26.4‰) and the composition of the light hydrocarbons reflect the idea that the natural gas is organic in origin, thermogenic, and mainly terrigenous‐sourced. The evolution of a transitional to continental depositional environment of the source rocks results in the variation in the geochemical characteristics of the Upper Palaeozoic gas in the study area. Analysis of fluid inclusions indicates a long and continuous period of natural gas charging in the study area from 165 to 65 Ma. Sandstone bodies close to or interbedded with the source rocks made the gas charging from the source rocks to the reservoirs over a short distance with high efficiency, while faults and fractures provided paths for the gas migrating to reservoirs vertically far from the source rocks. The huge gas generation potential of the source rocks and continuous distribution pattern of sandstone bodies provides favourable conditions for the development of a large‐scale natural gas reservoir. [ABSTRACT FROM AUTHOR]

Lacustrine stromatolites provide high-resolution and sensitive palaeoenvironmental and palaeoclimatic records of their respective drainage basins and beyond. A well-developed stromatolite bed was discovered within the clastic deposits of the Early Miocene Taxihe Formation in the southern margin of the Junggar Basin, north of the Tian Shan Mountains. Their sedimentological features indicate a near-shore stable environment of a shrinking lake. The study of the stable oxygen and carbon isotopes in this stromatolite bed revealed that δ18O V-PDB values range from −11.3‰ to −5. 6‰ and those of δ13C V-PDB from −1.8‰ to 1.7‰. Lower values −10. 2‰ and −8. 2‰, respectively, were determined from nearby lacustrine limestones of Oligocene age. The co-variation and overall increasing trend of the δ18O and δ13C values indicate deposition in a closed basin during a period of aridification. This environmental change can be related to the major uplift of the Tian Shan Mountains, the southern border of the Junggar Basin, during the Early Miocene. Several δ18O and δ13C records of lacustrine stromatolites ranging in age from Oligocene to Middle Miocene were reported: from localities in the Northern Tibetan Plateau and western Qaidam Basin. The similarity of the individual stable isotope records in stromatolites from Northwest China, indicate an underlying regional cause. These stromatolites were deposited during the period of major uplift of the Tibetan Plateau and the Tian Shan Mountains. It is therefore concluded that the stromatolite records provide local snapshots of the effect of this major process on atmospheric precipitation and environmental conditions in Northwest China. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]