New Benthic Fossils from the Late Ediacaran Strata of Southwestern China

The Jiangchuan Biota from the Jiucheng Member(Mb.)of the Dengying Formation(Fm.),discovered in Jiangchuan,eastern Yunnan,China,is marked by copious macrofossils at the apex of the Ediacaran strata.This fauna features benthic algae with varied holdfasts and other fossils of indeterminate taxonomic affinity and is compositionally unique compared to the Shibantan and Gaojiashan biotas of the Dengying Fm.and the Miaohe and Wenghui biotas of the Doushantuo Fm.,elsewhere in China.One novel benthic saccular macroalgal fossil,named here Houjiashania yuxiensis gen.and sp.nov.,from the Jiangchuan Biota is based on fossils that are sausage-shaped,elongate,tubular,ranging from 0.3 to 4 cm in length,and up to 0.8 cm in diameter.One terminus is blunt and rounded to an obtuse angle,the other is bent with a spread-out surface resembling a holdfast,suggesting a three-dimensional thallus.Thin,stipe-shaped outgrowths,likely vestiges of sessile saccular life forms,are prevalent in macroalgal fossils of analogous size and shape,as well as present brown algae Scytosiphonaceae,such as Colpomenia and Dactylosiphon.The new findings augment the diversity of benthic algae,such as those known from the Early Neoproterozoic Longfengshan Biota in North China.The benthic algal macrofossils in the Jiucheng Mb.add to knowledge of Late Ediacaran metaphyte diversification and offer more clues about the evolutionary positioning of primitive macroalgae.The co-occurrence of numerous planktonic and benthic multicellular algae and planktonic microbes might have facilitated ecologically the more extensive later Cambrian explosion evidenced by the Chengjiang Biota in Yunnan.

Characterization and spatial analysis of coseismic landslides triggered by the Luding Ms 6.8 earthquake in the Xianshuihe fault zone, Southwest China

On September 5, 2022, a magnitude Ms 6.8 earthquake occurred along the Moxi fault in the southern part of the Xianshuihe fault zone located in the southeastern margin of the Tibetan Plateau,resulting in severe damage and substantial economic loss. In this study, we established a coseismic landslide database triggered by Luding Ms 6.8 earthquake, which includes 4794 landslides with a total area of 46.79 km^(2). The coseismic landslides primarily consisted of medium and small-sized landslides, characterized by shallow surface sliding. Some exhibited characteristics of high-position initiation resulted in the obstruction or partial obstruction of rivers, leading to the formation of dammed lakes. Our research found that the coseismic landslides were predominantly observed on slopes ranging from 30° to 50°, occurring at between 1000 m and 2500 m, with slope aspects varying from 90° to 180°. Landslides were also highly developed in granitic bodies that had experienced structural fracturing and strong-tomoderate weathering. Coseismic landslides concentrated within a 6 km range on both sides of the Xianshuihe and Daduhe fault zones. The area and number of coseismic landslides exhibited a negative correlation with the distance to fault lines, road networks, and river systems, as they were influenced by fault activity, road excavation, and river erosion. The coseismic landslides were mainly distributed in the southeastern region of the epicenter, exhibiting relatively concentrated patterns within the IX-degree zones such as Moxi Town, Wandong River basin, Detuo Town to Wanggangping Township. Our research findings provide important data on the coseismic landslides triggered by the Luding Ms 6.8 earthquake and reveal the spatial distribution patterns of these landslides. These findings can serve as important references for risk mitigation, reconstruction planning, and regional earthquake disaster research in the earthquake-affected area.

Comparative study of different machine learning models in landslide susceptibility assessment: A case study of Conghua District, Guangzhou, China

Machine learning is currently one of the research hotspots in the field of landslide prediction.To clarify and evaluate the differences in characteristics and prediction effects of different machine learning models,Conghua District,which is the most prone to landslide disasters in Guangzhou,was selected for landslide susceptibility evaluation.The evaluation factors were selected by using correlation analysis and variance expansion factor method.Applying four machine learning methods namely Logistic Regression(LR),Random Forest(RF),Support Vector Machines(SVM),and Extreme Gradient Boosting(XGB),landslide models were constructed.Comparative analysis and evaluation of the model were conducted through statistical indices and receiver operating characteristic(ROC)curves.The results showed that LR,RF,SVM,and XGB models have good predictive performance for landslide susceptibility,with the area under curve(AUC)values of 0.752,0.965,0.996,and 0.998,respectively.XGB model had the highest predictive ability,followed by RF model,SVM model,and LR model.The frequency ratio(FR)accuracy of LR,RF,SVM,and XGB models was 0.775,0.842,0.759,and 0.822,respectively.RF and XGB models were superior to LR and SVM models,indicating that the integrated algorithm has better predictive ability than a single classification algorithm in regional landslide classification problems.

Geochemistry, zircon U–Pb geochronology, and Hf isotopes of S-type granite in the Baoshan block, constraints on the age and evolution of the Proto-Tethys

Geochemistry, zircon U–Pb geochronology, and Hf isotope data for the Early Paleozoic granites in the Baoshan Block reveal the Early Paleozoic tectonic evolution of the Proto-Tethys. The samples are high-K, calcalkaline, strongly peraluminous rocks with A/CNK values of 1.37–1.46, are enriched in SiO2, K2O, and Rb, and are depleted in Nb, P, Ti, Eu, and heavy rare earth elements,which indicates the crystallization fractionation of the granitic magma. Zircon U–Pb dating indicates that they formed in ca. 480 Ma. The Nansa granites have εHf(t) values ranging from-16.04 to 4.36 with corresponding TC DMages of 2.10–0.81 Ga, which suggests the magmas derived from the partial melting of ancient metasedimentary with minor involvement of mantle-derived components. A synthesis of data for the Early Paleozoic igneous rocks in the Baoshan block and adjacent(Tengchong,Qiangtang, Sibumasu, Himalaya, etc.) blocks indicates that these blocks were all aligned along the proto-Tethyan margin of East Gondwana in the Early Paleozoic. The Early Paleozoic S-type granites from Nansa were generated in a high-temperature and low-pressure(HTLP) extensional tectonic setting, which resulted from Andean-type orogeny instead of the final assembly of Gondwana or crustal extension in a non-arc environment. In certain places, an expanding environment may exist in opposition to the tectonic backdrop of the lithosphere’s thickening and shortening, leading the crust to melt and decompress,mantle-derived materials to mix, and a small quantity of peraluminous granite to emerge.

Prediction of Ground Vibration Induced by Rock Blasting Based on Optimized Support Vector Regression Models

Accurately estimating blasting vibration during rock blasting is the foundation of blasting vibration management.In this study,Tuna Swarm Optimization(TSO),Whale Optimization Algorithm(WOA),and Cuckoo Search(CS)were used to optimize two hyperparameters in support vector regression(SVR).Based on these methods,three hybrid models to predict peak particle velocity(PPV)for bench blasting were developed.Eighty-eight samples were collected to establish the PPV database,eight initial blasting parameters were chosen as input parameters for the predictionmodel,and the PPV was the output parameter.As predictive performance evaluation indicators,the coefficient of determination(R2),rootmean square error(RMSE),mean absolute error(MAE),and a10-index were selected.The normalizedmutual information value is then used to evaluate the impact of various input parameters on the PPV prediction outcomes.According to the research findings,TSO,WOA,and CS can all enhance the predictive performance of the SVR model.The TSO-SVR model provides the most accurate predictions.The performances of the optimized hybrid SVR models are superior to the unoptimized traditional prediction model.The maximum charge per delay impacts the PPV prediction value the most.

Geology and mineralization of the Dongping supergiant alkalic-hosted Au-Te deposit(>100 t Au)in Northern Hebei Province,China:A review

The Dongping deposit is the largest alkalic-hosted gold deposit in China containing>100 t of Au.This paper presents a new understanding for Dongping ore system,based on the previous studies.The mineralization originally occurred at 400-380 Ma,simultaneous with emplacement of the Shuiquangou alkaline complex,and was overprinted by the hydrothermal activity in the Yanshanian.Isotope compositions of ores indicate metals of the deposit are mainly provided by the Shuiquangou complex.Ore-forming fluids are characterized by increasing oxygen fugacity and decreasing sulfur fugacity,while tellurium fugacity increased in the Stage II-2 and decreased in Stage II-3.These systematic changes are closely related to the processes of mineral precipitation and fluid evolution.Sulfide precipitation from Stage Ⅰ to Stage Ⅱ was triggered by fluid boiling,which leads to the precipitation of Pb-Bi-Te,due to decrement of sulfur fugacity.Condensation of gas phase containing high concentration of H_2Te leads to precipitation of Te-Au-Ag minerals and native tellurium.Based on these hypotheses,this paper present a polyphase metallogenic model as follow.During the Devonian,fluids were released from alkaline magmas,which carried ore-forming materials form the surrounding rocks and precipitate the early ores.During the Jurassic-Cretaceous,fluorine-rich fluids exsolved from highly factionated Shangshuiquan granite,which extracted and concentrated Au from the Shuiquangou complex and the Sanggan Group metamorphic rocks,and finally formed the Dongping gold deposit.

Kinematic deformation and intensity assessment of the 2021 Maduo M_(S)7.4 earthquake in Qinghai revealed by high-frequency GNSS

Rapid acquisition of the kinematic deformation field and seismic intensity distribution of large earthquakes is crucial for postseismic emergency rescue,disaster assessment,and future seismic risk research.The advancement of GNSS observation and data processing makes it play an important role in this field,especially the high-frequency GNSS.We used the differential positioning method to calculate the 1 HZ GNSS data from 98 sites within 1000 km of the M_(S)7.4 Maduo earthquake epicenter.The kinematic deformation field and the distribution of the seismic intensity by using the peak ground velocity derived from displacement waveforms were obtained.The results show that:1)Horizontal coseismic response deformation levels ranging from 25 mm to 301 mm can be observed within a 1000 km radius from the epicenter.Coseismic response deformation on the east and west sides shows bilateral asymmetry,which markedly differs from the symmetry presented by surface rupture.2)The seismic intensity obtained through high-frequency GNSS and field investigations exhibits good consistency of the scope and orientation in the high seismic intensity area,although the former is generally slightly smaller than the latter.3)There may exist obstacles on the eastern side of the seismogenic fault.The Maduo earthquake induced a certain tectonic stress loading effect on the western Kunlun Pass-Jiangcuo fault(KPJF)and Maqin-Maqu segment,resulting in higher seismic risk in the future.

A new genus of galeaspids(jawless stem-Gnathostomata)from the early Silurian Chongqing Lagerstätte,China

The early Silurian Chongqing Lagerstätte(middle Telychian)yields exceptionally preserved articulated jawless and jawed fishes.Here,we describe a new eugaleaspiform(Galeaspida,jawless stem-Gnathostomata),Miaojiaaspis dichotomus gen.et sp.nov.,from the Chongqing Lagerstätte in Xiushan,Chongqing,China.The new form resembles Tujiaaspis vividus in the short medial dorsal canal,and the presence of the branching ends of the lateral transverse canal.They differ in that T.vividus has highly developed subordinate branches of the sensory canals that form a reticulate sensory canal system,and the median dorsal opening is more elongated.Our phylogenetic analysis recovers M.dichotomus and T.vividus as a monophyletic clade(Tujiaaspidae fam.nov.),which is supported by two synapomorphies:the short medial dorsal canal,and the branching ends of the lateral transverse canal.Tujiaaspidae forms a trichotomy with Shuyuidae and a clade comprising Anjiaspis,Sinogaleaspidae,Yongdongaspidae,and the‘eugaleaspid cluster’.The sensory canal patterns in galeaspids are compared to show the transformation sequence of the sensory canal system in Eugaleaspiformes.

Rb-Sr and Sm-Nd Isochron Ages of the Dongmozhazhua and Mohailaheng Pb-Zn Ore Deposits in the Yushu area, southern Qinghai and Their Geological Implications

Located on the northeast margin of the Qiangtang terrane between the Jinshajiang suture zone and Bangonghu-Nujiang suture zone,the Dongmozhazhua and Mohailaheng Pb-Zn deposits in the Yushu area of Qinghai Province are representative Pb-Zn deposits of the Pb-Zn-Cu polymetallic mineralization belt in the northern part of the Nujiang-Lancangjiang-Jinshajiang area,which are in the front belt of the Yushu thrust nappe system.The formed environments of these two deposits are different from those of sediment-hosted base metal deposits elsewhere in the world.The authors hold that they were formed during the Indian-Asian continental collision and developed within the fold-thrust belt combined with thrust and strike-slip-related Cenozoic basins in the interior of the collisional zone.Studying on the metallogenic epochs of these two deposits is helpful to the understanding of ore-forming regularity of the regional Pb-Zn-Cu mineralization belt and also to the search for new deposits in this region.The age of the Dongmozhazhua deposit has been determined by the Rb-Sr isochron method for sphalerite residues,whereas the age of the Mohailaheng deposit has been determined by the Rb-Sr isochron method for sphalerite residues and the Sm-Nd isochron method for fluorite.The age of the Dongmozhazhua deposit is 35.0-±0.0 Ma （（87Sr/86Sr）0=0.708807） for sphalerite residues.The age of the Mohailaheng deposit is 32.2±0.4 Ma （（87Sr/86Sr）o=0.708514） for sphalerite residues and 31.8±0.3 Ma （（143Nd/144Nd）o=0.512362） for fluorite with an average of 32.0 Ma.Together with the regional geological setting during mineralization,a possible tectonic model for metallogeny of the Dongmozhazhua and Mohailaheng Pb-Zn deposits has been established.These two ages are close to the ages of the Pb-Zn deposits in the Lanping and Tuotuohe basins,indicating that it is possible that the narrow 1000-kilometer-long belt controlled by a thrust nappe system on the eastern and northern margins of the Tibetan plateau could be a giant Pb-Zn mineralized belt.

REE geochemistry of gangue minerals and their geological significance in the Muli antimony ore deposit in Yunnan, China

The Muli antimony deposit is located in the Au-Sb polymetallic metallogenic belt in south-eastern Yunnan,China.In this paper,we investigated the concentrations of trace elements in gangue minerals,mainly calcite,quartz,and pyrite,which were formed at different metallogenic stages.Meanwhile,the host rocks,predominantly composed of limestone,are also analysed for comparison.The calcite from the Nadan ore section is enriched with medium-heavy rare earth elements(M-HREEs),likely due to the presence of a high concentration of Fe and Mn impurities,which results in the preferential enrichment of M-HREEs in the calcite.Alternatively,the calcite may be precipitated from the M-HREE・rich granitic leaching fluid.In the Muli ore section,both quartz and pyrite in the metallogenic period show enrichment with light rare earth elements(LREEs),and the wall rock is also enriched with LREEs,which indicates that the wall rock material was involved in the metallogenic process.The W-shaped tetrad effect of quartz in the late metallogenic stage was interpreted to determine extensive flu id-rock interactions in highly fractionated Si-rich systems.Fe and Mn impurities cause M-HREE to be preferentially enriched with calcite to some extent.Whether mineralization is related to granite deserves further study.Eu and Ce anomalies of different types of gangue minerals indicate that the temperature and the fO2 were constantly changing during mineralization,and the temperature of the main ore-stage was higher than 200°C in an oxidized state.The various REE patterns,LREE/HREE and(La/Yb)N values,reveal that there may be multi-sources and multi-stage hydrothermal activities in the Muli antimony deposit.The REE distribution patterns of minerals are likely interfered with by many internal and external factors.Studies on REE characteristics of calcite,quartz,pyrite and limestone in the Muli antimony deposit have greatly improved the understanding of ore-forming fluids.When we traced the origin and evolution of ore・forming fluids by means of mineral REE distribution patterns,in addition to the determination of inclusions of ore minerals related to mineralization and the in situ analysis methods performed by LA-ICP-MS,we should also com・bine the REE characteristics of various minerals or trace the ore-forming fluids with multiple methods.

Discovery and Geological Significance of Neoproterozoic Metamorphic Granite in Jimo, Shandong Province, Eastern China

During the 1：50000 regional geological survey in Jimo, east Shandong Province, Paleoproterozoic metamorphic supracrustal rocks and Neoproterozoic metamorphic plutonite were newly discovered. These rocks displayed inclusions which had occurred in the Mesozoic granite, and the main lithologies are schist, granulite, marble, and granitic gneiss. Geochemical analyses suggest that Neoproterozoic metamorphic plutonite are characterized by high-K, metaluminous to weakly peraluminous. They are enriched in LILE and depleted in HFSE, with moderately enrichment of LREE, weak fractionation of LREE from HREE and negative Eu anomalies. The surface age of plutonic rocks in the survey area is 770.2±2.4 Ma, representing the age of magma crystallization, which is agreement with the the Neoproterozoic magmatic event after Rodinia supercontinent in the northern margin of Southern China continental block. In addition, the age of sporadic distribution （298 Ma and 269 Ma） is mixed zircon age, representing the rocks experienced metamorphism in Indosinian period. According to the associated mineral assemblages, and the characteristic metamorphic minerals and temperature pressure conditions, four metamorphic facies were identified, including amphibolitic, epidote amphibolite, greenschist, and mid-high pressure greenschist. Analysis of tectonic setting suggests that granitic gneiss is formed in an extensional environment and was involved from the continental margin magmatic arc to intraplate environment. Jimo is distributed in the east of Zhuwu fault, and has the same Spatial distribution location with the Weihai uplift UHP metamorphic belt rocks. The metamorphic rocks in Jimo area have similar geochemical characteristics of elements, tectonic setting and retrograde metamorphism with that in the Sulu UHP metamorphic belt. Therefore, Zhuwu fault may be the boundary fault of Sulu UHP metamorphic belt.

Zircon Dating and Geological Implications of Granitic Gneiss in the Metamorphic Zone of Gaoligong Mountains in Western Yunnan, China

The general classification of intermediate-acid intrusive rocks in the metamorphic zone of Gaoligong Mountains as one of the metamorphic terranes of Proterozoic Gaoligong Mountains is problematic regarding the intrusion stage and age, as well as the subsequent metamorphism and deformation. In this study, we investigated granitic gneiss in the metamorphic zone of Gaoligong Mountains based on the 1：50,000 regional geological survey of Qushi Street （2011-2013） and SHRIMP U-Pb zircon geochronology. Results showed that the SHRIMP U-Pb zircon dating of granitic gneiss ranged from 163.5±5.7 Ma to 74.0±2.0 Ma. Thus, the granitic gneiss was grouped into orthometamorphic rocks （metamorphic intrusions）. The dating data of granite rocks associated with intense metamorphism and deformation were divided into three groups, 163.5±5.7 to 162.3±3.1 Ma, 132.2-101.0 Ma and 99.4±3.5-74.0±2.0 Ma, which respectively represented three independent geologic events including an important magma intrusion with superimposed metamorphic effects in the late Middle Jurassic, regional dynamic metamorphism and superimposed reformation of fluid action in the early Cretaceous, and dynamic metamorphism dominated by ductile shear and metamorphism starting from the late Cretaceous.

Helium and argon isotopic compositions of the Longquanzhan gold deposit in the Yishu fault zone and their geological implications

The Longquanzhan gold deposit hosted in granitic cataclasites with mylontization of the foot wall of the main Yishui-Tangtou fault. 3He/4He ratios in fluid inclusions range from 0. 14 to 0. 24 R/Ra,close to those of the crust-source helium. 40Ar/36Ar ratios were measured to be 289-1811, slightly higher than those of atmospheric argon. The results of analysis of helium and argon isotopes suggested that ore-forming fluids were derived chiefly from the crust. The δ18O values of fluid inclusions from vein quartz range from -1.78‰ to 4.07‰, and the δD values of the fluid inclusions vary between -74‰ and -77‰. The hydrogen and oxygen isotope data indicated that the ore-forming fluid for the Longquanzhan gold deposit had mixed with meteoric water in the process of mineralization. This is consistent with the conclusion from the helium and argon isotope data.

Comprehensive suitability evaluation of urban geological environment in Zhengzhou-Kaifeng area

Suitability evaluation of urban geological environment is an important basic work in city planning and construction. With Zhengzhou-Kaifeng area as the research area, this paper discusses AHP and fuzzy comprehensive evaluation methods to classify impact factors at different levels, makes a mixing evaluation of the basic factors and comprehensive factors so as to correct the uncertainty of the weight of the basic factors in the initial evaluation and establish the corresponding evaluation index system, and carries out urban geological environment suitability evaluation in study area. Furthermore, this paper partitions the suitability of the research area according to evaluation results into five zones. It puts forward opinions and suggestions for the construction of research area, which have certain practical significances.

Evaluation of groundwater potential and eco-geological environment quality in Sanjiang Plain of Heilongjiang Province

Sanjiang Plain of Heilongjiang Province has become an important commodity grain base in our country after the construction of more than a century. Groundwater is the main water source for industrial and agricultural production and daily life in the area. With the large-scale development and construction in this area, there are a series of ecological and environmental geological problems, such as the reduction of groundwater resources, which seriously restricts the sustainable development of local agriculture and society as well as economy. Based on the characteristics of three-dimensional flowof groundwater in Sanjiang Plain, this paper adopts the simulation software Visual MODFLOW to evaluate groundwater exploitation potential. The results show that overall there is a certain exploitation potential of Sanjiang Plain groundwater but it is unevenly distributed, and overdraft phenomenon exists in seven farms such as Baoquanling and Chuangye. Based on analytic hierarchy process, the evaluation result of eco-geological environment quality in Sanjiang Plain shows that 94.5% of the region features good geological environment quality, medium stability and medium bearing capacity. The study can provide geological evidence for optimal allocation of water resources, land planning and regulation, and the high and stable yield of the commodity grain base in Sanjiang Plain.

Response to the Lomagundi-Jatuli Event in the southwestern margin of the Yangtze Plate:Evidence from the carbon and oxygen isotopes of the Paleoproterozoic Yongjingshao Formation

The Lomagundi-Jatuli Event(LJE)refers to the significant positive carbon isotope excursion in seawater constituents that occurred immediately after the increase in atmospheric oxygen content during the Paleoproterozoic(2.22-2.06 Ga).Theδ^(13)C values of 46 dolostone samples collected from the Paleoproterozoic Yongjingshao Formation varied in the range of 0.05‰-4.95‰(V-PDB;maximum:4.95‰)in this study,which may be related to the multicellular eukaryotes in the Liangshan Formation in the Yimen Group.They are much higher than theδ^(13)C values of marine carbonates(-1.16‰on average).Theδ^(13)C values of other formations in the Paleoproterozoic Yimen Group are negative.The notable positive carbon isotope anomalies of the Yongjingshao Formation indicate the response to the LJE at the southwestern margin of the Yangtze Block,which is reported for the first time.Furthermore,they are comparable to theδ^(13)C values of carbonates in the Dashiling Formation of the Hutuo Group in the Wutaishan area in the North China Craton,the Wuzhiling Formation of the Songshan Group in the Xiong'er area,Henan Province,and the Dashiqiao Formation of the Liaohe Group in the Guanmenshan area,Liaoning Province.Therefore,it can be further concluded that the LJE is a global event.This study reveals that LJE occurred in Central Yunnan at 2.15-2.10 Ga,lasting for about 50 Ma.The macro-columnar,bean-shaped,and microfilament fossils and reticular ultramicrofossils of multicellular eukaryotes in this period were discovered in the Liangshan Formation of the Yimen Group.They are the direct cause for the LJE and are also the oldest paleontological fossils ever found.The major events successively occurring in the early stage of the Earth include the Great Oxygenation Event(first occurrence),the global Superiortype banded iron formations(BIFs),the Huronian glaciation,the Great Oxygenation Event(second occurrence),the explosion of multicellular eukaryotes,the positive carbon isotope excursion,and the global anoxic and selenium-rich sedimentary event.The authors think that the North China Craton and the Yangtze Craton were possibly in different tectonic locations of the same continental block during the Proterozoic.

Study of Organochlorine Pesticides in Eco-geochemical Survey of Soil in Shandong Province

Based on a comprehensive eco-geochemical survey of Shandong Province, the differences in pesticide residue situation and contents of DDTs and HCHs in the soils of Yantai City and Southwest Shandong Province(abbreviated as SSP) were studied in this paper. The results showed that the detection rates of DDTs and HCHs in the soil of SSP were apparently higher than Yantai City. However, the mean contents of DDTs and HCHs in the soil of Yantai were 9 and 25 times of SSP, respectively, and higher than the mean contents of many other cities and areas. p,p′-DDE was the main pesticide residual form in the soil of SSP. It is recognized as the degradation product of DDTs in oxidation environment in past, nevertheless, 5.52% of the soils in Yantai City still have a little of DDT input recently, which has posed a big impact on soil environment quality. β-HCH was the main form of the four isomers of HCHs in Yantai City, and α-HCH/γ-HCH in SSP was low. These reveal that the residual time of HCHs in the soils of both the two areas has a long period. After primary analysis, the risk of DDTs and HCHs in the soil of SSP is low, but DDTs in the soil of Yantai City still has a certain risk.

Survey and Assessment of Land Ecological Quality in Cixi City

Soil,atmosphere,water and quality of agricultural product constitute the content of land ecological quality.Cixi City,through survey pilot project of basic farmland quality,carried out high precision soil geochemical survey and survey of agricultural products,irrigation water and air quality,and established ecological quality evaluation model of land.Based on the evaluation of soil geochemical quality,we conducted comprehensive quality assessment of atmosphere,water,agricultural products,and assessed the ecological quality of agricultural land in Cixi City.The evaluation results show that the ecological quality of most agricultural land in Cixi City is excellent,and there is ecological risk only in some local areas such as urban periphery.The experimental results provide demonstration and basis for the fine management of basic farmland and ecological protection.

The Program Construction Method of Navigation Format Files GPX and KML Based on Geological Exploration Point Information

GPX and KML are open and multi-purpose,which are widely used in many fields such as basic geological survey,geochemical survey,geophysical survey,engineering survey and so on.Based on the analysis of the syntax features,basic structure and expression of GPX and KML files,this paper discussed the construction methods of GPX and KML files by taking the construction of navigation files of point information as an example.According to the specifications of GPX and KML files,an automatic construction program of GPX and KML files is designed and compiled,which realizes the automatic generation of batch point navigation files and supports in related software,and shows good effects of holding and displaying,which is helpful to simplify work flow and improve work efficiency.

Discussions about Construction of Agricultural Ecological Geochemical Survey Database

[Objectives]To realize proper,update and dynamic analysis of the results of ecological geochemical survey,and provide useful information for government macro-decisions,land resources planning,agricultural structure adjustment,ecological environment monitoring,governance and evaluation.[Methods]This paper conducted the analysis with the aid of the computer database technology and GIS technology,as well as the regional geochemical database information system(GeoMDIS)developed by the Development Research Center of the China Geological Survey.[Results]It established a database of agricultural ecological geochemical survey in the lower Yellow River Basin of Shandong Province,realized the collection,storage,update and statistical analysis management of various sample data.[Conclusions]Through the discussion on the construction of agricultural ecological geochemical survey database,it is expected to provide an effective information platform for the future use of these data to serve government macro-decisions,land and resource planning,agricultural structure adjustment,ecological environment improvement,monitoring,governance and evaluation.