Abstract:Based on the groundwater level measured in 2009 in the downstream of Yellow River plain, combined with the isotopic (¹⁸O and ³H)geochemistry of surface water and the groundwater, the lateral seepage scope and variation of downstream of Yellow River were analyzed after 20 years' operation of Xiaolangdi reservoir. The result indicates that in 20 years of operation of Xiaolangdi reservoir, the current scope of lateral seepage of the downstream of Yellow River will be between 5-25 km, with the largest scope of about 25 km in Xinxiang-Kaifeng and the smallest scope of 5 km in Binzhou. Compared with affected scope of lateral seepage in the initial operation of Xiaolangdi reservoir, the affected scope increased by about 0.5-5 km in the west of Binzhou, with most significant increment along Xinxiang-Zhengzhou, and slight decrement in the east of Binzhou. The affected scope of lateral seepage was mainly controlled by medium condition, recharge source condition and energy condition. After Xiaolangdi reservoir was put into operation, the channel was cut down, the permeability of the river bed was enhanced, and the "adsorption and purification" ability of the river bed material to the Yellow River water was reduced. Then, the water quality of Yellow River has a significant impact on the groundwater quality along the river. Hence, the control and improvement of water quality of Yellow River was the basis to ensure the high-quality development of the ecological environment in the basin of down-Yellow River.

Abstract:Based on the analysis of historical underwater topography and water level data, field measurement, laboratory test and comprehensive evaluation, the influence of major water conservancy projects on the channels and shorelines of the middle and lower reaches of the Yangtze River is studied. Some new progresses have been made. Firstly, a multi-mode sensor system was innovatively constructed to integrate the measurements of land and underwater hydrodynamic, sedimentary and geomorphic characteristics and data acquisition. Secondly, it was found that the main channel of the Yangtze River experienced strong erosion, arc collapse, and strip collapse. Thirdly, the hanging sand and bed sand were coarsened. The resistance of the river bed dropped, which caused the forming of the erosion type chain bead sand wave. The main piers of the Yangtze River Bridge were subjected to serious erosion. Finally, the tidal limit obviously moved up, and the geomorphology of the river changed significantly. On this basis, it is suggested that the investigation, monitoring and mechanism analysis should be strengthened on main river channel, high and steep slope along the bank, the estuary where the tributaries join the main stream, bank collapsing, cross-river bridge pier scour and so on. These results are of great significance to the protection and restoration of the bank and beach of the Yangtze River, the waterway regulation, the coastal flood control, and the maintenance of the piers of the Yangtze River Bridge.

Abstract:In order to support the scientific management of land resource in Xiong'an New District and improve the assessment system of soil pollution in China, a metal smelting area in the District was selected to conduct geological survey. Total 541 surface soil samples collected from the smelting area were analysed for the concentrations of eight heavy metal elements of Cd, Hg, Pb, As, Cu, Zn, Cr, Ni and pH values. The principal component analysis method was used to study the combination and distribution characteristics of the heavy metals. The methods of the single pollution index, Nemerow synthesis pollution index, geological accumulation index and potential ecological hazard index and health risk assessment model were adopted to evaluate the degree and risk of heavy metals pollution in soil. The results show that the excessive concentrations of Cu, Zn, Cd, Pb in soil of the area are mainly influenced by smelting activity, the high value anomalies of As and Pb are principally caused by irrigation of the polluted groundwater from Tanghe River. The order of over-standard rate of the single pollution indices of the elements is Cd>As> Cu>Zn>Pb>Hg>Cr=Ni. The assessment results by the Nemerow synthetic pollution index method show that fifty-four percent of the samples reaches the pollution standard. The order of over-standard rate of the geological accumulation indices is Cd>Cu>Pb>As>Zn>Hg>Ni>Cr, of which the extremely heavy pollution ratios for the elements of Cu, Cd, Zn, Pb and As are 13.5%, 10.2%, 9.1%, 10.9% and 17.2%, respectively. Cd and Hg are the major ecological risk elements. The ratio of moderate-considerable potential ecological risk of Cd is 65.2%, and that of Hg is 71.3%. As, Cr and Pb are of major non-carcinogenic factors. There are 95.2% of the samples (As, Cr, Pb) with non-carcinogenic risk index over 1, and 29 samples with carcinogenic index of As over 10^-4 to children, indicating that heavy metals in the soil of study area have a relatively high health risk to children.

Abstract:Zhaojue County is a typical Yi-inhabited County in the hinterland of Daliang Mountain. It is also a state-level deeply impoverished county with traditional agriculture as the main living means. In order to promote the transformation of agricultural development mode, modern agricultural park has been constructed in Zhaojue County. Through Unmanned Aerial Vehicle(UAV) aerial survey, the high-resolution images of the proposed park were obtained,and object-oriented image analysis software was used to quickly extract land use status and other information. Combined with other collected data, eight evaluation factors were selected, including slope, aspect, fault, geological hazard, land use, irrigation, transportation and nature reserve. With the support of Geographic Information System (GIS), the single-factor of land adaptability was evaluated first, and then the comprehensive evaluation was conducted. The results show that the land suitability of the proposed park is much suitable, with the total area of 2.56 km², accounting for 79.26%, more than 3/4. It is suitable for building a modern agricultural industrial park, standardized vegetable greenhouses, and open field vegetable cultivation base. After construction, it will not only provide vegetable supply to the surrounding cities, but also increase the income of farmers around the park, and promote the poverty alleviation of farmers around the park, showing good development prospects. Small UAV remote sensing system has the advantages of flexibility and low cost. It can quickly obtain the basic data of small area and large-scale agricultural industrial park, and has ideal application effect in land suitability evaluation of small areas in Southwest China. The natural environment and social environment of small area land are relatively single, and many large regional land suitability evaluation indexes are not fully applicable, so it is necessary to select appropriate evaluation indexes according to the main purpose of land use.

Abstract:Driven by the goal of "carbon neutrality", it is a general trend for the global energy system to develop towards cleaner, low-carbon or even carbon-free. In response to the demand for the transition to clean energy, the methods of statistical comparison, classified summary and comprehensive analysis are adopted to analyze and study the role and demand of critical minerals in department such as batteries, electricity networks, low-carbon power generation and hydrogen. Combined with the problems, such as high geographical concentration of current critical mineral output, long cycle of project development, and decline in resource quality, that cannot meet the needs of clean energy transition, it is proposed to ensure the diversified supply of key minerals, promote technological innovation in all links of the value chain, scale up recycling, enhance supply chain resilience and market transparency. It is suggested to mainstream higher environmental, social and governance standards into the main process, and strengthen international collaboration between producers and consumers.

Abstract:As a kind of zero carbon and clean energy, the development and utilization of geothermal energy is of great value for carbon neutralization. From 2015 to 2020, the global geothermal power generation increased by about 3649 GW, an increase of about 27%. Total installed capacity of geothermal utilization increased by 52.0%. The sum of the two, the used heat energy increased by 72.3% over 2015. The direct utilization of geothermal energy in the world can prevent 78.1 million tons of carbon and 252.6 million tons of CO₂ from being emitted into the atmosphere every year. The world geothermal energy development presents the following five trends:development of unconventional geothermal system, development of offshore geothermal resources, reduction of drilling cost and cooperation of thermal energy production with petroleum, increase of the development and utilization of shallow geothermal energy, strengthening of the research and development of aquifer thermal energy storage technology.

Abstract:Niobium and tantalum resources are widely distributed in the world. Their endogenous metallogenic deposits are mainly hosted in pegmatite, rare-metal granite, carbonatite, and alkaline rocks. Their exogenetic deposits are mostly the products of secondary enrichment through exogenous processes such as weathering and deposition from endogenous deposits. The metallogenic epoch of pegmatite-hosted deposits has a large span from 3.08 Ga to 0.19 Ga; alkaline rock-hosted deposits are at 2.25-1.35 Ga and 0.75-0.19 Ga respectively; carbonatite-hosted deposits are mainly in 0.75-0.6 Ga and 0.4-0.35 Ga; and granite-hosted deposits are mainly distributed in the middle and late stages of 0.75-0.19 Ga. At present, carbonatite-hosted niobium deposits and pegmatite-hosted tantalum deposits are the main exploration targets.

Abstract:Heavy metals are difficult to be biodegraded, meanwhile easy to form toxic environmental factors. The evolution of heavy metals pollution in sediments is a common global ecological environmental problem since industrialization. To reveal the relationship between human activities and heavy metals deposition in Sanduao Bay of Fujian Province, 6 sediment cores were collected in the Bay for grain size testing, ²¹⁰Pb dating and assay of Cu, Pb, Zn, Cr, As, Cd and Hg contents. The results show that over the past century, heavy metal contents in sediments of Sanduao Bay exhibit a significant increase trend. The top is 1.01-2.8 times higher than the bottom, and the evolution process can be divided into three stages, relatively stable period during 1900-1950s, slowly increasing during 1950-2000s, and sharply increasing since the 2000s. Those changes are closely related to population and economic development. The content of heavy metals in landward zone is generally higher than that in seaward zone, and the evolution trend of sediments in landward zone has been different from the sediments in seaward zone since 2000s. The heavy metals content of sediments in landward zone has decreased, while the heavy metals content of sediments in seaward zone has increased sharply in Sanduao Bay. This spatial difference is closely related to the change of grain size and regional industry distribution. Heavy metals have a great impact on the marine ecological environment of Sanduao Bay. As the increasing intensity of fish farming in the Bay, enough attention should be paid to the rapid increase of heavy metal contents in the Bay in recent years, so as to improve the management and remediation to avoid marine ecological damage.

Abstract:High concentration of ammonium nitrogen in groundwater is a potential threat to drinking water safety and ecological environment. Compared with nitrate nitrogen, the high concentration of ammonium nitrogen not only has a variety of man-made sources, but also the natural sedimentary environment is the main cause of high ammonium groundwater. The rapid urbanization of the Pearl River Delta was taken as a case study to investigate the environmental characteristics and driving factors of high ammonium groundwater by means of mathematical statistics and principal component analysis methods. The results show that the concentration of ammonium in the groundwater in the study area is as high as-180 mg/L. Among 1539 groups of groundwater samples, 69 groups of high-ammonium groundwater with ammonium ion concentration greater than 10 mg/L, 23 groups of high-ammonium fertilizer water yield ammonium ion concentration greater than 30 mg/L. Compared with the historical hydrochemical data from 2005 to 2008, the proportion of high-ammonium groundwater sample sites in the pore aquifers of newly-added construction land from 2009 to 2018 is 6.5%, which is 1.25 times that of ten years ago. The high ammonium groundwater is distributed in the silty and silty aquifer developed in the low lying basement and depression at the bottom of Quaternary in the delta plain area. The sediments rich in organic matter and total organic carbon, such as silt layer, are the "ammonium producing layer" in the Pearl River Delta region, and the mineralization of organic nitrogen is the main driving force of the high ammonium groundwater in the urbanized pore aquifer in the delta plain region. The leakage and infiltration of domestic sewage from urbanization expansion and ammonium-rich industrial wastewater are the important sources of ammonium-nitrogen in high ammonium-rich groundwater in the urban-rural junction. The reduction environment rich in organic matter is the main cause of the high ammonium groundwater in the delta plain. Lixiviation, cation exchange adsorption and sea-land interaction are the main hydrogeochemical processes of the evolution of high-ammonium groundwater water quality in the Pearl River Delta.

Abstract:Carbonate sediment is widely developed above Lower Permain Angjie Formation in Coqin basin,which was disintegrated by previous research to establish several formations. Five conodont zones of Lower Permian-Lower Triassic were identified in the carbonate rocks through conodont studies, namely Mesogondolella siciliensis -Sweetognathodus subsymmetricu zone, Mesogondolella idahoensis zone, Jingondolella aserrata zone, Clarkina meishanensis zone, Neospathodus dieneri zone, and the stratigraphic age of the Xiala Formation was constrained at Lower Permian Kungurian-the later of Middle Permian.

Abstract:Based on the measurement of γ radiation dose rate, radon radioactivity and ²³⁸U, ²³²Th, ²²⁶Ra, ⁴⁰K radionuclide testing, the radioactive anomalies of coal-bearing strata in East China were identified to evaluate the specific activities of natural radio-nuclides in air, solid, water and plant in the typical area of the regional coal-bearing occurrences. The results show that there are significant differences in natural radioactivity between the Carboniferous-Permian common coalfields and the Cambrian stone coal occurrences. The γ radiation dose rate and radon radioactivity measured on the surface of ordinary coal mining area are generally in the background level range, and the nuclide content of solid medium, water body and plant samples in the mining area is in the normal level, and there is no radioactive pollution. The stone coal distribution zone in East China belongs to the high background region of radioactive γ radiation, and the ²³⁸U and ²²⁶Ra obviously are accumulated in coal, coal gangue, soil, rock, and the spatial distribution of these natural radionuclides shows significant variability. In the monitoring area, the effective dose of γ radiation exceeds the international limit value of 1 mSv/a, the total effective dose exceeded 2 mSv/a, and total α and total β concentrations of the groundwater are 10~30 times of the limit values. The γ radiation shows higher background value in the stone coal-bearing area, and radioactive pollution cannot be ignored. The public in the stone coal area of the East China is subjected to higher radiation dose, and groundwater, building material and plant have been contaminated by radioactive pollution sporadically. It is necessary to strengthen monitoring of radioactive environment and take appropriate control measures.

Abstract:The Jiama deposit is one of super large-sized deposits with high grade and one of the most explored and studied deposits in the Gangdese metallogenic belt of Tibet. Because the South-Pit segment host large-sized skarn Cu-Pb-Zn ore bodies with high-grade, it has been given priority to mining. However, its diagenesis, mineralization and the relationship with main segment are still unclear. Based on detailed borehole logging and field geological evidences, it is determined that the mineralization is related to intermediate-felsic porphyries. The high-precision U-Pb dating of ore-bearing granodiorite porphyry yields the age of 15.5±0.3 Ma, which is consistent with the Re-Os age of molybdenite (15.23±0.22Ma). As the important part of Jiama polycentric complex mineralization model, the skarn ore body in South-Pit segment is mainly distributed on the contact between marble and hornfels. The skarn should be the result of Miocene magmatism and destroyed by the slide nappe fault and secondary faults. For the future exploration in South-Pit, more attention should be paid to the study of alteration and mineralization of ore-bearing porphyry and skarn, and to the locating of the ore-related fluid center.

Abstract:The Xianggou scheelite deposit, discovered in the Wangjiaping-Longtougou-Xiajiadian gold metallgenic belt in recent years, is another new geology survey progress in south Qinling related to W mineralization. The composition of scheelite was analyzed by LA-ICP-MS, together with Sm-Nd isotope dating of symbiotic calcite, to clarify the origin of Xianggou scheelite. The results show that scheelite exists in three generations,from the early rhythmic zonal scheelite to the late aggregate one,indicating that the scheelite undergone multiple migrations. The scheelites have high F content with low Au content. The total amount of rare earths is high, ranging from 5.44×10^-6 to 382.67×10^-6, with an average of 95.48×10^-6. The REE pattern is flat without MREE enrichment,with negative Eu anomaly, similar to the type Ⅱ REE type classified by Ghaderi et al. (1999). All these data support that the W mineralization in the Xianggou area might be related to W-bearing quartz vein with genetic links to magmatic hydrothermal activities. The Sm-Nd isotope dating result of the symbiotic calcite (195 Ma) indicates that the deposit was formed in the late Indosinian.

Abstract:The Qiucheng Mo deposit is located in the Dehua-Yongxi-Yongtai ore-concentrated area of Fujian Province. It is the only one large-scale molybdenum deposit there. Ore bodies are mainly distributed in the outer contact of granite porphyry, fissure filling of the middle-late Proterozoic metamorphic rocks and the late Jurassic granites. The molybdenite is disseminated, veins and lump. Re-Os dating of six molybdenite samples collected from the main ore body in the deposit yields the model age from 150.1 Ma to 152.8 Ma, the isochron age of(150.8±1.6)Ma, and the weighted average age of(151.8±0.9)Ma. It can thus be considered that the deposit was formed in the late stage of Late Jurassic and related to the large-scale volcanic and intrusive rock activities. According to the rhenium content(14.31×10^-6-45.8×10^-6(one is 174.7×10^-6))and the ratio of Re and Os(much greater than 4)of molybdenum samples, it is inferred that the ore-forming materials of the deposit were mainly derived from the crust and possible addition of small amount of mantle materials. The Qiucheng Mo deposit may be the product of conversion process from the end of collision to the beginning of extension of the Paleo-Pacific plate towards the continental margin of East Asia.

Abstract:Xuzhou is located in the southeast of the north China craton. Alkaline ultrabasic rocks-basic rocks are widely developed in and around it, where there are some diamondiferous rocks, but mainly kimberlite. During the prospecting of primary diamond deposit, the diamondiferous rocks were discovered in Bailushan, north of Xuzhou. The SiO₂ content of olive basalt ranges from 42.64% to 51.13%, K₂O+Na₂O from 2.57% to 5.93%,Al₂O₃ from 10.48% to 13.53%,and MgO content from 3.11% to 19.34%. On the TAS diagram, the points of basic rocks in this area all fall into the range of basalt, indicating high potassium calcium alkalinity. Trace element signatures indicate that samples from Bailushan are close to the OIB and volcanic arc regions. The higher Ba/Th ratio of enriched endmember suggests that the basalts contain lower continental crust materials. Therefore, the wide range of elements geochemistry and isotopic composition of olivine basalts is not mainly caused by crustal contamination, but because the source area contains residual recirculation subcontinental crust. These geochemical characteristics suggest that the Bailushan olivine basalt in Xuzhou is related to the kimberlite in Liaoning and Shandong, which provides a favorable clue for diamond prospecting in this area.

Abstract:In order to explore the distribution and enrichment of strontium in groundwater under the control of water flow system in karst area, the Maoping river and Jiuwanxi karst watershed in Zigui were taken as the study case, and 415 groups of water samples and 93 groups of rock samples were collected from typical springs, typical surface water and main water-bearing rocks during 2016-2018. The analytical results indicate that strontium is mainly enriched in the strata of the Jialingjiang Formation, Loushanguan Formation and Dengying Formation deposited in tidal flat and lagoon sedimentary facies, and mostly exists in the form of celestite, strontianite and other minerals. The water type of Sr-rich groundwater is mainly SO₄ type, Cl type, and SO₄-HCO₃ type. In the water flow system,, the strontium-rich minerals are less in strata above vadose zone, mainly affected by leaching;both celestite and strontianite are not saturated in shallow groundwater, but they tend to be saturated in a few deep groundwater. The closed reduction environment rich in gypsum and celestite is conducive to the enrichment of strontium in groundwater.

Abstract:The Litang mélange, in which conserves complete mélange system is developed, including remnant of ophiolite, oceanic island blocks, intra-oceanic arc blocks, flysch formation, remnant of rift, high-ultrahigh pressure belt, is located in the middle part of the Ganzi-Litang ophiolite mélange belt around Xinlong-Litang county town, and is an ideal object for the restoring and inversing of the evolution of the Ganzi-Litang ocean basin. On the basis of previous studies and combined with recent research results, the mineral composition, tectonic environment and formation age of Litang melange are described in detail, which further constrain the space-time, nature and evolution of Ganzi-Litang ocean basin. The results of LA-ICP-MS zircon U-Pb dating show that the age of ophiolite is (346±17)Ma, (286.2±5.1)Ma, (219.5±2.2)Ma, (216.1±2.3)Ma, the age of oceanic island is (271±10)Ma, (245.1±1.5)Ma, (211.8±1.8)Ma, and the latest age of detrital zircon is (196±3)Ma in the siltstone interlayer of Ruihuanshan Formation in Jurassic. Combined with a large number of fossil identification results, the analysis shows that the age of the Litang mélange probably ranges from the Middle Devonian to the Early Cretaceous, indicating that it records the continuous evolution of Ganzi-Litang ocean basin from the Middle Devonian to early Cretaceous. With all the achievement mentioned above, the formation and evolution mode of the Ganzi-Litang ocean basin from the Late Paleozoic to the Mesozoic is approximately established.

Abstract:The tectonic framework on the southern margin of South China Block (SCB) between Permian and Triassic Periods has long been a controversial subject. The regional geological survey and research show that the Xinxing pluton in western Guangdong was emplaced in Late Triassic (240-224 Ma) rather than Jurassic, whose main lithology is medium-fine and fine-grained porphyritic monzonitic granite. The Xinxing granite is characterized by high potassium calc-alkaline and peraluminous-strongly peraluminous series, which is enriched in LREE, Rb, U, and depleted in HREE, Nb, Ta, Zr, Hf, Ti. It exhibits relatively low ε_Nd(t) (-11.5- -10.5) and ε_Hf(t) (-2.9- -10.3) values, showing the crustal source affinity. Therefore it is suggested that the start of the Indosinian tectonic-magmatic event in Western Gongdong probably took place in ~250 Ma. These new geochemical and geochronological evidence have furthermore restricted the timing of tectonic activities on the southern margin of SCB between later Permian (Darongshan pluton) and later Triassic (Xinxing pluton). Hence, the closure time of East Paleo-Tethys Ocean would be about 250 Ma, and the continental-continental collision between Indo-China Block and SCB continued till 240-224 Ma.

Abstract:The study of plant succession and climate change in Cretaceous is of great significance for the understanding of formation and evolution of the present ecological environment. The study on the palynology from the Yixian Formation can provide palynology data and lay the basis on Early Cretaceous stratigraphic classification and correlation in the northeastern area of Kailu basin. Based on the analysis of sporo-pollen fossils of 47 species from 39 genera recognized from the bottom of well QIV-65-136 in the Qianjiadian depression, Kailu Basin, the Cyathidites-Pinuspollenites-Protoconiferus assemblage was established. According to the age range of typical species, content change on key species and horizontal contrast, this assemblage should be dated as the early Early Creataceous, the horizon is equivalent to the Yixian Formation. The palynoflora shows the Coniferales plants on the high elevation mountain around the lake, accompanied by Podocarpaceae, Taxodiaceae, Cycadaceae, Araucariaceae and Cheirolepidiaceae plants, the fern such as Osmundaceae, Cyatheaceae, Schizaeaceae plants growing under the trees near the lake. Vegetation is occupied by coniferous, representing a humid temperate to subtropical zone.

Abstract:The field investigation, remote sensing image interpretation and comprehensive analysis of meteorological data were used to analyze the coupling relationship between wind field and sedimentary system. The analysis results show that the change of wind field is not only controlled by the change of prevailing wind system and monsoon, but also affected by geomorphology and lake land wind generated by lake effect and other factors. The influence of wind field on the Qinghai Lake sedimentary system embodies in the local area of dry and wet climate, source of supply, and degree of wave and the strength of the offshore current. The difference of dry and wet climate in local region results in the difference of vegetation coverage and the difference of weathering resistance. The weak weathering resistance zones provide ample source for sand accumulation. The waves and offshore current resulting from prevailing wind direction strengthen the transport and transform function for sand body.

Abstract:The Bohai Bay and its coastal area are one of the most attractive hotspots for the studies of marine geology and Quaternary geology in China. Although many achievements have been made, some fundamental geological questions still remain unsolved. For example, did the Yellow River flow through Bohai Bay during the Late Pleistocene? How was the multi-stage delta lobes of the Yellow River Delta distribute in the Bohai Bay? Those questions have been attracting great attentions from marine geologists in China. Based upon ~2000 km seismic profile data, two ~30m-length boreholes (BHZK2017-1 and BHZK2017-2) in Bohai Bay during 2016-2017, numerous AMS ¹⁴C and OSL dating results and previous achievements of seismic profiles and boreholes, the stratigraphic sequences was divided into four seismic units (SU1-SU4) and six sedimentary units (DU1-DU6) in descending order, namely prodelta, tidal flat, floodplain, river channel, land-sea interaction facies and lacustrine/marsh facies, respectively. The general stratigraphic framework and sedimentary evolution of Bohai Bay since the Late Pleistocene were accordingly analyzed. It is revealed that the Yellow River likely flowed from near the East-West to the central basin of the Bohai Sea through the northern part of the Bohai Bay during 21.8-9 cal ka BP. Moreover, four subaqueous delta lobes distributed from the northwest to the south of the Bohai Bay since the Holocene were formed during 1400 AD-present, 1048-1128 AD, 700 BC-11 AD and 1855-present, respectively. Two northern subaqueous delta lobes were mainly related to the Haihe River, and the other two southern delta lobes were likely to be the Qikou superlobe and the modern Yellow River Delta superlobe respectively. The studies upon the sedimentary evolutions, paleochannel development and the subaqueous delta distribution since the Late Pleistocene would be conducive to the layout of coastal engineering programs and the mitigation of geological hazards in Bohai Bay.

Abstract:As an important part of Northern China Desert, Hulun Buir sandy land is of great significance to the study of dust system in Asia. The characteristics of heavy minerals and the composition of Sr-Nd isotopes are the important tools to reveal the sediment evolution process and trace the provenance. But the "grain size effect" caused by sedimentary sorting has always been the limiting factor for the composition of heavy minerals and Sr-Nd isotopes in sandy land. Totally 19 aeolian sand and fluvial sand samples were collected from Hulun Buir sandy land and screened to analyze the material composition and discuss the effect of separation on the composition of heavy minerals and Sr-Nd isotopes. Among them, 12 sub-samples (<73 μm and 73-125 μm) were identified and analyzed for heavy minerals, and 23 sub-samples (<63 μm,<30 μm and <11 μm) were determined for Sr-Nd isotopes. The results show that there are significant differences in heavy mineral content, heavy mineral index (ATi, GZi and ZTR) and heavy mineral assemblage with different particle sizes. The stable and extremely stable minerals are concentrate preferentially onto the finer particles, which enhances the overall stability of the fine-grained sediments. Different from previous studies on Sr-Nd isotopic grain size control, our results show that the ⁸⁷Sr/⁸⁶Sr ratio is slightly affected by the grain size effect, but the Nd isotopic composition is significantly affected by it, and the coarse-grained components tend to have a higher Nd isotopic ratio. The Sr-Nd isotopic composition of Hulun Buir sandy land has "time effect". It shows that the geochemical composition of the dust source area is unstable. This study is of great significance for the understanding of Asian aeolian dust system study using heavy mineral and Sr-Nd isotopic composition. The wide or multiple grain size window as well as substantial amount of samples must be considered for source tracing.

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