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Reconstructing forest and grassland cover changes in China over the past millennium

Science China Earth Sciences 2025年第1期68卷 94-110页

作者： Fanneng HE Fan YANG Yafei WANG Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Key research institute of Yellow River Civilization and Sustainable development Henan University University of Chinese Academy of Sciences

Historical forest and grassland cover changes not only are critical indicators for quantifying ecological and environmental change processes but also serve as fundamental data for long-term climate change simulations and terrestrial ecosystem carbon emission assessments. However, because of limitations in historical data, quantitative estimations and spatially gridded reconstructions of these changes remain challenging, necessitating further methodological exploration. This study focused on China's present-day land area over the past millennium, objectively capturing the characteristics and drivers of forest and grassland cover changes. On this basis, using the forest transition theory and the space-for-time substitution method, we depicted the historical deforestation process as an inverted “S” curve and developed a model to reconstruct historical forest area changes based on the functional relationship between the forest area and population size dynamics. Subsequently, a gridded forest allocation model was established on the basis of deforestation tendencies. For the grassland cover, we implemented regionspecific methods, such as the cropland area deduction method and the habitat constraint method, to quantitatively reconstruct historical changes. Consequently, we obtained provincial forest and grassland area changes over the past millennium and mapped 10-km-resolution gridded data of forest and grassland cover. The results indicated the following.(1) The methods developed using population data as a proxy objectively reproduced the spatiotemporal evolution of forest and grassland cover in China over the past millennium. These feasible methods offer a novel pathway for the quantitative reconstruction of historical forest and grassland cover changes.(2) The data indicated that China's forest area generally decreased over the past millennium, characterized by a “decrease-then-increase” pattern. The forest area experienced three distinct phases: a slow decline(AD 1000

关键词： Land use and land cover change Forest Grassland Quantitative reconstruction Gridded reconstruction China historical period

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Formation mechanism of deep natural hydrogen in the Sichuan Basin

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Science China Earth Sciences 2025年

作者： Xiaomei WANG Kun HE Chunlong YANG Hao XIE Xiaobo WANG Yitong LYU Linfeng XIE Shuichang ZHANG research institute of Petroleum exploration & development PetroChina Key Laboratory of Petroleum Geochemistry China National Petroleum Corporation International Center for Isotope Effects research School of Earth Science and Engineering Nanjing University

As a potential renewable and clean energy source,the distribution and exploration prospects of natural hydrogen have garnered widespread ***,the limitations in understanding the formation mechanisms and accumulation patterns of underground natural hydrogen have significantly constrained its efficient exploration and *** study reports H2content and isotopes in natural gas from deep formations in sedimentary basins through geochemical analysis of 58 conventional gas samples from the Sinian to Triassic strata in the central Sichuan *** discovered that H2content in deep natural gas in central Sichuan generally exceeds 0.1%,with a maximum of 1.6%,and hydrogen isotopes (δ2HH2) range from-850‰to-586‰.Analysis of the geological conditions,hydrogen generation mechanisms,and isotope fractionation characteristics in the study area confirms that microbial fermentation or in-situ organic matter cracking are not effective pathways for deep *** with helium content and isotope analysis of the natural gas,it is inferred that the volcanic basement in the central Sichuan area is the potential source rock for natural H2in the Sinian to Triassic ***,H2originates from the radiolysis of water and hydrothermal reactions of Fe（II） in the basement ***,a diffusion fractionation model reveals significant isotope fractionation during the migration and accumulation of deep H2into sedimentary reservoirs,which lead to anomalously light δ2HH2in deep natural gas in central *** indicates that the underground natural hydrogen accumulation is in a long-term dynamic process,with simultaneous H2accumulation and dissipation in the gas *** research not only elucidates the formation mechanism of deep H2but also provides insights for the resource potential of natural hydrogen in sedimentary basins.

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Nanocarrier-mediated siRNA delivery:a new approach for the treatment of traumatic brain injury-related Alzheimer's disease

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Neural Regeneration research 2025年第9期20卷 2538-2555页

作者： Jie Jin Huajing Zhang Qianying Lu Linqiang Tian Sanqiao Yao Feng Lai Yangfan Liang Chuanchuan Liu Yujia Lu Sijia Tian Yanmei Zhao Wenjie Ren institute of Disaster and Emergency Medicine Tianjin UniversityTianjinChina Key Laboratory for Disaster Medicine Technology TianjinChina henan Medical Key Laboratory for research of Trauma and Orthopedics The Third Affiliated Hospital of Xinxiang Medical UniversityXinxiangHenan ProvinceChina Clinical Medical Center of Tissue Engineering and Regeneration Xinxiang Medical UniversityXinxiangHenan ProvinceChina institutes of Health Central Plain Xinxiang Medical UniversityXinxiangHenan ProvinceChina School of Public Health Xinxiang Medical UniversityXinxiangHenan ProvinceChina

Traumatic brain injury and Alzheimer's disease share pathological similarities,including neuronal loss,amyloid-βdeposition,tau hyperphosphorylation,blood-brain barrier dysfunction,neuroinflammation,and cognitive ***,traumatic brain injury can exacerbate Alzheimer's disease-like pathologies,potentially leading to the development of Alzheimer's *** offer a potential solution by facilitating the delive ry of small interfering RNAs across the blood-brain barrier for the targeted silencing of key pathological genes implicated in traumatic brain injury and Alzheimer's disease.U nlike traditional approaches to neuro regeneration,this is a molecula r-targeted strategy,thus avoiding non-specific drug *** review focuses on the use of nanocarrier systems for the efficient and precise delive ry of siRNAs,discussing the advantages,challenges,and future *** principle,siRNAs have the potential to target all genes and non-targetable protein s,holding significant promise for treating various *** the various therapeutic approaches currently available for neurological diseases,siRNA gene silencing can precisely"turn off"the expression of any gene at the genetic level,thus radically inhibiting disease progression;however,a significant challenge lies in delivering siRNAs across the blood-brain *** have received increasing attention as an innovative drug delive ry tool fo r the treatment of brain *** are considered a potential therapeutic strategy with the advantages of being able to cross the blood-brain barrier,targeted drug delivery,enhanced drug stability,and multifunctional *** use of nanoparticles to deliver specific modified siRNAs to the injured brain is gradually being recognized as a feasible and effective *** this strategy is still in the preclinical exploration stage,it is expected to achieve clinical translation in the future,creating a new field of molecular tar

关键词： blood-brain barrier cognitive dysfunction exosomes gene silencing immunotherapy inorganic nanomaterials liposome nanoparticles neuroinflammation polymer nanoparticles stem cells

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Growth patterns and dynamics of mud cracks at different diagenetic stages and its geological significance

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International Journal of Sediment research 2014年第1期29卷 82-98页

作者： Zhen-yu ZHAO Yan-ru GUO Yan WANG Hong LIU Qing ZHANG research institute of Petroleum exploration and development research institute of Petroleum exploration & development of Changqing oilfield

This paper discusses the growth stages,spatial structures,quantitative fitting relationships among various parameters,growth patterns and influencing factors of mud cracks by field survey,core observation and SEM *** study shows that:(1) Mud crack growth can go through three stages,*** syndiagenetic stage,the burial diagenetic stage(including early diagenetic stage,middle-late diagenetic stage) and the epidiagenetic stage.(2) Quantitative fitting relationships among various parameters allow a great significance to describe the spatial structure,the regional distribution and the growth environment of mud cracks.(3) Mud crack growth has three models,such as the unilateral growth model including the linear growth pattern,the curvilinear growth pattern and the bifurcation growth pattern,the multilateral growth model including the inteisectional growth pattern,the join growth pattern and the dispersed growth pattern,and the mixed growth model including the combination of any patterns listed above.(4) Modern mud crack growth usually undergoes four *** beds in sand-mud rhythmic strata can play a lubricative role on crack growth and provide enough sandy deposits for filling cracks.(5) Mud crack growth usually produces bifurcation and bifurcation angles which are mostly 120° or 90° that are related to sediment heterogeneity and released energy.(6)Factors affecting mud crack growth cover many aspects:clay content and salinity can control the number of mud cracks in different areas;terrain can control mud crack morphology;and different sedimentary cycles can control the growth patterns and filling models of mud cracks.

关键词： Mud crack Growth pattern Geological model Lagoon Coastal sediment

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Spatiotemporal evolution of Ediacaran-Cambrian(ca. 551–523 Ma)sponges in South China and their simulated contributions to marine oxygenation

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Science China Earth Sciences 2025年

作者： Yan YE Lei ZHANG Can CHEN Shan CHANG Yuhao YI Qinglai FENG State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences(Wuhan) School of Earth Science China University of Geosciences(Wuhan) Department of Geology Lund University institute of Sedimentary Geology Chengdu University of Technology Key Laboratory of Deep-time Geography and Environment Reconstruction and Applications of Ministry of Natural Resources Chengdu University of Technology Second Geological Brigade of Hubei Geological Bureau College of Urban and Environmental Sciences Hubei Normal University exploration and development research institute SINOPEC Jianghan Oilfield Company

The origin and evolution of sponges have attracted interest, not only because they are among the most basal metazoans, but also because they act as important ecological engineers in the ocean. Previous research suggested that sponge groups diversified quickly during the Cambrian Series 2, while Terreneuvian sponge fossils are conspicuously rare and poorly substantiated. Yet, an increasing number of sponge spicules have been reported from the Ediacaran-Cambrian(E-C, ca.551–523 Ma) transitional carbonates/cherts worldwide, particularly in South China, which calls for updated discussions. Ocean oxygenation has been widely proposed to play a critical role in organismal evolution, but its relationship with sponges is unclear and falls into a “chicken-egg” dilemma. In this study, we summarize reported sponge spicule distributions from five E-C sections in South China to investigate the early evolutionary pattern of siliceous sponges. According to current stratigraphic correlation,monaxons first appear in the late Ediacaran in the intrashelf basin-slope area, and then potentially expand to the continental shelf and deep basin in the lower Cambrian. In these sections, the abundance, size, and diversity of monaxons increase upwards,followed by the appearance of diaxons, triaxons and then polyactines. Despite the uncertain affinity of the sponge fossils, it is possible that siliceous hexactinellids evolved later than siliceous demosponges, given that the earliest spicule assemblages are exclusively composed of monaxons, which commonly form bundles comparable to modern demosponges. New geochemical data from the Sifangjing section, Guizhou Province and the Yanziqiao section, Hunan Province, South China show that the appearance of sponges usually corresponds to anoxic environment. In addition, we applied the recently proposed Biological Pump, Oxygen and Phosphorus(BPOP) model to trace the evolution of oceanic oxygen concentrations with the radiation of sponges. The results indic

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Genesis of the high gamma sandstone of the Yanchang Formation in the Ordos Basin,China

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Petroleum Science 2013年第1期10卷 50-54页

作者： Liu Huaqing Li Xiangbo Liao Jianbo Liu Xianyang research institute of Petroleum exploration and development-Northwest research institute of exploration and development Changqing Oilfield Company

Recently, more attention has been paid on the high gamma sandstone reservoirs of the Yanchang Formation in the Ordos Basin, China. These high gamma sandstones have logging characteristics different from conventional sandstones, which influences the identification of sandstone reservoirs. Zhang et al （2010） proposed that the high gamma sandstones of the Yanchang Formation might be the result of re-deposition of homochronous sedimentary tufts or previous tufts as a part of the sandstone. However, we present a different viewpoint： 1） few tufts or tuff debris have been found in the high gamma sandstones of the Yanchang Formation; 2） high gamma （or high Th content） sandstones of Yanchang Formation are not related to either clay minerals or feldspar; 3） the heavy minerals in the sandstone reservoirs of the Yanchang Formation are dominated by zircon, which is characterized by abnormally high Th and U contents, up to 2,163 ppm and 1,362 ppm, respectively. This is sufficient to explain the high gamma anomaly. The conclusion is that the high gamma value of the Yanchang Formation sandstones might be caused by zircon with high Th and U contents in sandstones rather than from the tuff components.

关键词： High gamma sandstones reservoir zircon Yanchang Formation Ordos Basin

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Geological features and hydrocarbon accumulation in the Xinken oil field,Tarim Basin

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Chinese Journal Of Geochemistry 2013年第4期32卷 367-379页

作者： SONG Lichen ZHU Guangyou LIU Xingwang ZHU Yongfeng SU Jin WANG Kai research institute of Petroleum exploration and development PetroChina research institute of Petroleum exploration and development Tarim Oilfield CompanyPetroChina

Recently,a large-scale Ordovician oil and gas pool has been discovered in Xinken,north of the Tarim Basin,and it has strongly heterogeneous reservoirs and complicated fluid *** analyzing oil,gas and water samples collected from this area,in combination of field production and testing data,this study reveals that the Xinken oil pool contains dominantly normal oil characterized by low viscosity,low sulphur,and high *** has a low content of natural gas,which presents typical characteristics of wet gas and is oil-associated ***-gas correlation shows that the oil was from the Middle-Upper Ordovician source rocks and the charge and accumulation of oil and gas took place in the Late Hercynian *** by paleogeomorphology,sedimentary facies,ancient karstification,faults,and other factors in the Caledonian Period,the Ordovician carbonate reservoirs are dominated by dissolved pores,cavities and *** reservoir body of fractures and cavities is distributed in the shape of strip and laminate along faults and excellent reservoirs are mostly in the range of 70–100 m below the top of the Yijianfang *** a whole,the Xinken oil pool is a fracture-cavity pool controlled by interbedded karst reservoirs and is a complex composed of stacked karst fractures and cavities of various *** contains oil in large areas horizontally,which is quasi-laminated in distribution,and the accumulation of oil and gas is controlled by the distribution and development degree of the Ordovician carbonate *** study shows that this area has abundant resources and a great exploration potential for oil and gas.

关键词：塔里木盆地北部油气成藏地质特征碳酸盐岩储层石油伴生气油田储层控制非均质储层

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Evidence of the Near-Source Accumulation of the Tight Sandstone Gas in Northern Ordos Basin,North-Central China

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Acta Geologica Sinica(English Edition) 2017年第5期91卷 1820-1835页

作者： YANG Zhi LI Qiyan WU Songtao LIN Senhu LIU Xinshen research institute of Petroleum exploration & development Petro China research institute of exploration and development Petro China Changqing Oilfield Company

The tight sandstone gas in Upper Paleozoic Formation of the northern Ordos Basin is a typical giant unconventional tight gas province. Evidences from geochemistry, reservoir geology and paleotectonic setting all verify that the present-day tight sandstone gas accumulation in the Ordos Basin is the result of near-source accumulation. The evidences are listed as following： tight sandstone gas is mainly distributed in the area with high gas-generating strength; gas composition was not subjected tofractionation; gas saturation significantly decreases with the distance away from the source rocks; gas isotopes suggest their origin is the same and maturity is consistent with in-place source rocks; reservoirs have experienced three types of densification digenesis, including intense compaction, siliceous cementation and calcareous cementation, which took place before the formation of a large amount of tight sandstone gas, forming tight reservoirs with low porosity and permeability, fine pore throat and great capillary resistance; the paleo-structural gradient ratio is small from the main hydrocarbon generation period to present. It is indicated the present distribution of tight sandstone gas in the northern Ordos Basin is the result of near-source and short-distance migration and accumulation.

关键词： near-source accumulation tight sandstone gas coal measures unconventional gas geochemistry

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Distribution and significance of C~_(40) alkanes in the extracts of Cretaceous source rocks from the Songliao Basin

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Science China Earth Sciences 2007年第10期50卷 1510-1520页

作者： FENG ZiHui FANG Wei ZHANG JuHe LI ZhenGuang HUANG ChunYan WANG Xue ZHAO QinLing HUO QiuLi exploration and development research institute Daqing Oilfield Company Ltd. Daqing 163712 China Exploration and Development Research Institute Daqing Oilfield Company Ltd. Daqing 163712 China Exploration and Development Research Institute Daqing Oilfield Company Ltd. Daqing 163712 China Exploration and Development Research Institute Daqing Oilfield Company Ltd. Daqing 163712 China Exploration and Development Research Institute Daqing Oilfield Company Ltd. Daqing 163712 China Exploration and Development Research Institute Daqing Oilfield Company Ltd. Daqing 163712 China Exploration and Development Research Institute Daqing Oilfield Company Ltd. Daqing 163712 China Exploration and Development Research Institute Daqing Oilfield Company Ltd. Daqing 163712 China

Source rock extracts and crude oils from the Songliao Basin were analyzed by high-temperature gas chromatography (HTGC), gas chromatography-mass spectrometry (HTGC-MS) and gas chromatography-isotope ratio-mass spectrometry (GC-IRMS), for high molecular-weight alkanes. The distributions of n-alkanes in the Nenjiang Formation extracts are in the C14―C63 range; a bimodal distribution occurs in the C-21 and C21―40 regions. The C30―C37 n-alkanes are accompanied by C29―C35 hopanes, whereas the high molecular-weight C45―C47 n-alkanes co-occur with abundant isoalkanes, alkylcyclohexanes and alkylcyclopentanes. The high δ 13C values of the n-alkanes and the microscopic maceral compositions indicate a highly diversified organic source input for the Nenjiang Formation source rocks, ranging from aquatic plants, blue alge-bacteria, to land plant material. In contrast, n-alkanes in the rock extracts of the Qingshankou Formation are characterized by a single modal distribution, with relatively low abundances of C29―C35 hopanes, but high molecular-weight isoalkanes, alkylcyclohexanes and alkylcyclopentanes. The relatively low δ 13C values of C22―C44 n-alkanes and organic material compositions indicate that the source rocks in the Qingshankou Formation contain dominantly type I algal organic matter. The relative abundance of C+40 compounds in source rocks changes little at low maturity stage, but decreases drastically at higher maturity levels, with a concurrent reduction in the odd/even carbon predominance. In crude oils, in contrast, the relative abundance of C+40 compounds appears to relate closely with the oil source and oil viscosity.

关键词： Songliao Basin, source rock, high-temperature gas chromatography (HTGC), high-temperature gas chromatography-mass spectrometry (HTGC-MS), gas chromatography-isotope ratio-mass spectrometry (GC-IRMS).

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Oil and gas resource potential of the lower members of E_(h3) in the lower Tertiary of the Biyang Depression, China

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Petroleum Science 2012年第1期9卷 18-24页

作者： Gang Wenzhe Wang Qingyu Luo Jiaqun College of Geosciences China University of PetroleumBeijing 102249China exploration&development research institute Daqing Oilfield CompanyPetroChinaHeilongjiang 163712China research institute of Petroleum exploration and development Henan Oilfield CompanyS1NOPECHenan 473132China

The lower Tertiary Eh3 is divided into two sections： the upper members of Eh3 and the lower members of Eh3 in the Biyang Depression. The first section is generally regarded as a key target of oil and gas exploration, but the resource potential of the lower members of Eh3 has been neglected. We have obtained new knowledge about Eh3 from comprehensive geological research. The lower members of Eh3 are high-quality and main source rocks, which have good oil and gas resource potential. This is a new direction for oil and gas exploration. The geochemistry characteristics of source rocks of the lower members of Eh3 in the lower Tertiary of the Biyang Depression were analyzed in detail. A basin modeling method was applied to hydrocarbon generation of the lower and upper members of Eh3 source rocks, the oil and gas resource potential was comparatively analyzed, and then favorable tectonic zones were pointed out. In the lower members of Eh3, a set of semi-deep lake to deep lake high-quality source rocks occurs rich in algae organisms, mainly of type II1, with a high abundance of organic matter. Most of the source rocks are just in the peak stage of hydrocarbon generation, which is a favorable foundation for forming abundant oil and gas resources in the Biyang Depression. The comparative analysis of the hydrocarbon- generation quantities between lower and upper members of the Eh3 source rocks shows that the lower members of Eh3 have good oil and gas resource potential, and the hydrocarbon-generation quantity accounts for 51% of the total in Eh3. Specifically, the oil-generating quantity accounts for 50% of the total and the gas-generating quantity accounts for two thirds of the total. Therefore, source rocks in the lower members of Eh3 of the Biyang Depression have good oil and gas resource potential, which is a key factor for future deep oil and gas exploration.

关键词： Geochemistry source rocks hydrocarbon-generation potential Biyang Depression

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