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This paper is the research of tectonic deformation. [Objective] During the Indosinian orogeny, the collision and convergence of the South China, North China, and Qiangtang terranes triggered extensive granitic magmatic intrusions and fold deformation in the Songpan-Garzê region. To investigate their tectonic setting and evolutionary processes. [Methods] the authors analyzed the mineral compositions and geochemical characteristics of granitic intrusions.[Results] Four main types of granitic intrusions were identified: (1) biotite ± amphibole high-K calc-alkaline type, (2) peraluminous calc-alkaline type;(3) high-K alkaline type; (4) leucogranite type. Based on macro - and micro-structural features and regional unconformities, the tectonic deformation during this period was divided into two principal phases: D1 and D2.[Conclusions] The diverse types of granitic intrusions and structural deformations from different stages correspond to distinct tectonic environments during the syn-orogenic (collisional) and post-orogenic (extension) phases of the Indosinian orogeny.
Highlights：This study correlates the Indosinian magmatism with tectonic deformation in the Songpan-Garzê region and systematically investigates the tectonic-magmatic evolutionary processes during the Indosinian period.
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[Objective] The tectonic location of granitic mylonite in Qingling area of Jilin Province is located in the eastern part of the northern margin of the North China plate. The research is the great significance to the evolution of the Paleo-Asian Ocean tectonic domain and its transformation with the tectonic system of the Paleo-Pacific tectonic domain. [Methods] In this paper, it is the first time to study the petrography, LA-ICP-MS zircon U-Pb chronology and geochemical characteristics of the rock to determine its emplacement age, petrogenseis and its tectonic background. [Results]The zircon of granitic mylonite is semi-automorphic-automorphic and the oscillatory growth zone is obvious, suggesting its magmatic origin. The dating results show that the granitic mylonite was formed at 291±3.0 Ma, which is the product of the Early Permian magmatic event. The 40Ar/39Ar plateau age of biotite is 182.01±0.38 Ma, suggesting that the metamorphic deformation age is Early Jurassic. EBSD fabric analysis shows that the rocks in this area have undergone a regressive process of medium-high temperature to medium-low temperature to low temperature.The rock is characterized by high silicon (68.26% - 75.91%), high aluminum (12.32% - 15.17%), poor iron (Fe2O3 is 0.03-3.38), and geochemical characteristics show peraluminous. The rocks are enriched in light rare earth elements, depleted in heavy rare earth elements, and the differentiation of light and heavy rare earth elements is obvious. [Conclusions] The above characteristics indicate that it is the product of partial melting of argillaceous rocks in the lower crust. The 40Ar/39Ar plateau age of biotite is 182.01±0.38 Ma, suggesting that its metamorphic deformation is Early Jurassic. Combined with regional geological characteristics, the emplacement of Early Permian granitic mylonite should be related to the southward subduction of the Paleo-Asian Ocean. The metamorphic deformation of the granitic mylonite occurred in the early Jurassic, which may be related to the subduction of the Paleo-Pacific plate to the Eurasian plate.
Highlights: The Early Permian granitic mylonite was identified in the Qingling area of Jilin Province for the first time, and its systematic petrology, petrochemistry, isotope chronology and metamorphic deformation were studied. It is believed that its formation time is 291±3.0 Ma, and the deformation time is 182.01±0.38 Ma. Granitic mylonite was formed in the process of island arc magmatic activity under the background of subduction, indicating that the Early Permian Paleo-Asian Ocean Plate subducted to the North China Plate, and the Early Jurassic Paleo-Pacific Plate may begin to subduct to the Eurasian Plate.
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This paper is the result of rock geochemistry. [Objective] Xiaozhushan is located in the eastern extension of the northern Jiaonan Uplift, Sulu orogenic belt, Shandong Province,adjoining the Wulian-Qingdao fault. Mesozoic granites are widely exposed in this area. In the process of field exploration, the lightcolored granite profile with large mineral particles were founded, which determined as highly differentiated granite by geochemical tests. Highly fractionated granite is an important symbol of continental crust composition maturity. This study plays an important leading role in improving the types of granites in the study area, evaluating the ore-bearing potential of the study area, and exploring the large igneous rock province in eastern Shandong Province. [Methods]The petrography, major, trace and rare earth elements in whole rock, Sr-Nd-Pb isotope, zircon U-Pb dating and in-situ Hf isotope, X-ray diffraction and laser Raman spectroscopy, plagioclase electron probe and in-situ elemental scanning analysis of 8 samples obtained in the Xiaozhushan area were carried out, and the following conclusions were obtained. [Results]Petrography shows that the granite in the study area contains S-type granite characteristic mineral-cordierite, with pegmatite veins. The 10 000 Ga/Al-Zr diagram shows the granite rock type, belong to I and S granite. All samples are high-silica granites (SiO2 >71.9%) with high total alkali content (Na2O+K2O >8.5), belonging to the highpotassium calc-alkaline series. Calculation of the index of highly fractionated granites: most samples with obvious Eu negative anomaly (δEu=0.4-0.5) and the aluminum saturation index is higher (A/CNK >1.2), the differentiation index (DI) is above 90, and the saturation temperature of zircon reflects the magma origin temperature is 832-875 °C. Zircon Ti thermometer reflects that the crystallization temperature of magma is 618.8-726.44 ° C, which shows that magma differentiation experienced obvious cooling process. S-Nd-Pb isotopes show high ISr and low εNd(t), indicates that the sample magma source area is crust. Geochronology shows that the samples` age is 116.4 Ma, which belongs to the Early Cretaceous highly fractionated granite. [Conclusions]The above conclusions show that the highly differentiated granite in the study area is mainly crust-derived material, and mixed with mantlederived material. The process of differentiation experiences the separation and crystallization of minerals such as plagioclase and the accessory minerals like zircon and apatite. The magma rises along the cracks in the island arc, forming highly fractionated granite with ore-bearing potential.
Highlights: In this study, S-type granite was found in Xiaozhushan area. Through geochemical analysis, the source of rock material and tectonic background were clarified.
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This paper is the result of sedimentary environment. [Objective]The Middle Jurassic Yaopo Formation in the Muchengjian area of Xishan, Beijing, belongs to typical continental lacustrine deposits. This set of strata is the best developed and fully exposed sedimentary of Middle Jurassic sandstone, but its grainsize characteristics are not researched, which restricts the analysis and reconstruction of the Middle Jurassic sedimentary environment in North China. [Methods] Based on the outcrop profile of Panjiagou in Muchengjian area, Western Beijing, this paper calculates the relevant particle size parameters and Sahu function discriminant values through microscope observation, statistics and analysis, and the probability particle size curve, Friedmann particle size parameter scatter plot and C-M diagram were drawn, and the relevant parameters and images were comprehensively studied and analyzed, and the grain size characteristics and sedimentary environment of the sandstone of the Yaopo Formation were summarized. [Results] Relevant grain-size parameters of 18 sandstone samples from the target profile of the study area were as follows: (1) the average particle size ranges from 0.57-3.54 φ; (2) Standard deviation σ ranges from 0.42 to 1.03; (3) Skewness (SK1) range - 2.36-0.79; (4) kurtosis (KG) ranges from 0.90 to 1.27; the probability granularity accumulation curves are typical two-stage, three-stage and multi-stage forms. The C-M diagram of the sample shows that the sediments are mainly suspended and gradually suspended, which represent typical traction flow deposits. [Concluslions] SK1-σ1 scatter plots, probability accumulation curves, C-M plots, show that the sedimentary environment in the study area is shallow lake and delta sedimentation.
Highlights: The grain-size analysis method was systematically used to study and analyze the sandstone of Yaopo Formation in Muchengjian area of Xishan, Beijing for the first time, and the characteristic values of relevant grain-size parameters were obtained. At the same time, through comprehensive research analysis, beach-bar deposits in the area was firstly proposed.
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This article is the result of rock chronological research. [Objective] Multiple periods of granitic magmatic activity have developed in the Qinglong Kuancheng area of eastern Hebei Province, previous studies on the Dashizhu rock mass are relatively weak compared to the Dushan pluton, which is the largest Mesozoic intrusive rock in the eastern Hebei province. The formation age of the Dashizhu rock mass has always been controversial.This article aims to explore the formation age and geological significance of the Dashizhu rock mass in Kuancheng, eastern Hebei Province. [Methods] This article conducted LA-ICP-MS zircon U-Pb dating on the Dashizhu rock mass in Kuancheng County, Chengde, redefine the formation age of the intrusion body of the Dashizhu, which is disintegrated through regional geological survey.[Results] The Dashizhu pluton is divided into three stages. The stage of adamellite is divided into central and marginal phases according to mineral particle size, the authors selected two monzonitic granites diagenetic ages of 226 Ma and 214 Ma, which belong to the Late Triassic of the Mesozoic era. [Conclusions] Based on regional comparison and comprehensive research, it is preliminarily believed that the Kuancheng Dashizhu rock mass is a northeast intrusive extension of the southwestern Dushan pluton, the result will provide new ideas for searching gold mineralization zones in the eastern Hebei Province.
Highlights：Through zircon U-Pb geochronology and division of the Dashizhu rock mass, it is determined that the Dashizhu rock mass was formed in the Late Triassic. This result has important indicative significance to search Mesozoic gold deposits in eastern Hebei Province.
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This paper is the research on cobalt-nickel deposits. [Objective] Northern Hebei is located near the eastern part of the northern margin of the North China Craton, which is in the metallogenic prospect area of magmatic cobalt-nickel deposits on the northern margin of North China Craton, and there are abundant clues to cobalt-nickel mineralization. The study of the metallogenic conditions and types of cobalt-nickel deposits in Hebei Province is helpful to clarify the metallogenic potential and prospecting prospect of cobalt-nickel deposits in the province.[Methods] By summarizing the typical cobalt-nickel deposits at home and abroad, the ore-forming geological conditions in the province are compared. Based on the comprehensive analysis of relevant geological and mineral data, the metallogenic background, metallogenic regularity and prospecting potential of cobalt-nickel deposits in the province are summarized and analyzed. [Results] There are a large number of basic-ultrabasic rock bodies related to cobalt-nickel mineralization in the province, the strata and regional structures related to cobalt-nickel mineralization are widely distributed, and the cobalt-nickel ore-forming geological conditions are superior. The known cobalt-nickel deposits in the province are divided into nine genetic types of cobalt-nickel deposits related to intrusive magmatism, contact metasomatism, volcanism, ore-bearing fluid and sedimentary diagenesis, and the characteristics of mineralization, distribution and quantity of various types of cobalt-nickel deposits are summarized. [Conclusions] The nickel-cobalt deposits in Hebei Province have superior ore-forming geological conditions, rich and diverse genetic types, especially magmatic and skarn types have good metallogenic potential and prospecting prospect.
Highlights: The metallogenic geological conditions of cobalt-nickel deposits in Hebei Province are systematically summarized for the first time, and the genetic types of cobalt-nickel deposits in Hebei Province are comprehensively sorted out and summarized.
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This paper is the research of groundwater monitoring.
[Objective] In order to accurately obtain the basic information of groundwater, build a groundwater monitoring system, and ensure the orderly promotion of large-scale engineering construction and the construction of the ecological city of“water city communion”, Xiong’an New Area has implemented a shallow groundwater monitoring well construction project. [Methods] On the basis of the original national and provincial monitoring wells, the construction of shallow groundwater monitoring wells and the online monitoring system for the Xiong’an New Area were carried out in accordance with the distribution, recharge, runoff and discharge conditions of the shallow groundwater. [Results] The groundwater monitoring network consists of 41 groups and 109 wells has constructed in Xiong’an New Area, with a monitoring area of 1770 km2 , the main monitoring layers are the pore water aquifer of the loose sediments of the Quaternary with a shallow depth of 50 m (phreatic water and shallow confined water), and a comprehensive groundwater monitoring network integrating the collection of groundwater information, transmission, analysis and related services has been built. [Conclusions] The implementation of this project can realize comprehensive and systematic monitoring of shallow groundwater up to 50 m in Xiong’an New Area, which greatly improves the monitoring capacity of shallow groundwater, ensures the timeliness and accuracy of shallow groundwater information, and provides important basic data nd technical support for the high-quality construction and management of groundwater in Xiong’an New Area.
Highlights: An automatic monitoring network for shallow groundwater stratification was built for the first time in Xiong’an New Area. The monitoring of shallow groundwater in the Xiong’an New Area is divided into 3 to 4 layers, which greatly improves the monitoring accuracy and monitoring capacity of shallow groundwater, and provides important basic data and technical support for the high-standard and high-quality construction of the Xiong’an New Area and the government’s decision-making on water resources management.
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This paper is the study on the influence of moisture conditions on the frost heave characteristics.
[Objective] Frost heave is a common disease in the subgrade engineering of seasonal frozen soil areas. The aim of this paper is to systematically understand the frost heave laws of typical soil types in the seasonally frozen soil area. [Methods] This paper takes undisturbed natural silt clay obtained from in-situ drilling as the research object. A multi-channel fiber Bragg grating temperature measurement system is used to monitor the movement of the freezing front. A single-factor frost heave test is adopted to conduct closed/open system freezing comparison tests at temperature gradients of ﹣5 °C, ﹣15 °C, and ﹣25 °C. The characteristics of frost heave under different moisture conditions are explored. A wider range of natural initial moisture contents of undisturbed soil samples is selected to grasp the overall trend of rate changes frost heave. The main conclusions supplement and improve the previous research results. Under the closed system conditions, the change trends are basically the same, but under open system conditions, there are differences in the change trends, change boundary points, and extreme points of the frost heave rate. At the same time, a frost heave prediction equation under the influence of two factors is constructed. [Results] The results show that both the initial moisture content and the water replenishment conditions have a significant impact on the frost heave rate. Under closed system conditions, the frost heave rate of the soil increases first and then tends to be stable as the initial moisture content increases. Under open system conditions, it shows a parabolic response. The frost heave rates under different water replenishment system conditions differ by 2 to 5 times. The intrinsic factor determining the frost heave characteristics of natural silt clay is its structure. [Conclusions] The critical moisture content control indicators (24% for open system and 31% for closed system) and the frost heave prediction equation are proposed, which can provide certain references for the prevention and prediction of frost heave of silt clay in engineering projects in seasonally frozen soil areas with frequent groundwater activities.
Highlights：The field drilling of the original silty clay in the seasonal frozen area and different moisture content ranges were selected for frost heave tests to reveal the structural effects of frost heave in undisturbed soil, propose moisture thresholds for frost heave prevention and control, and analyze multimodal frost heave responses. the main conclusions complement the previous research results, and can provide data support for frost heave prevention and controlling and frost heave rate prediction.
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This paper is the result of geological hazard survey engineering. [Objective] To systematically analyze the material composition and deformation and failure characteristics of Baiyao landslide, the stability of landslide in the studied area is evaluate, reference is provided for urbanization construction and development, and guidance for regional landslide disaster prevention and control is provide. [Methods] Based on the field geological survey and field drilling, the material composition, deformation and failure characteristics of the landslide in Beiyao village, Yangcheng County, Shanxi Province, are analyzed in this paper. The stability coefficient of the landslide under different working conditions is calculated according to GB/T32864—2016, and the stability evaluation is carried out. [Results] (1) The main sliding direction of the landslide in Beiyao village is about 30°, the top elevation of the landslide slope is 750 m, the foot elevation is 629 m, the height difference is about 121 m, and the slope is about 30°. The landslide body length is about 305 m, the width is about 660 m, the thickness of the landslide body is about 5—10 m, the area is about 201 300 m2 , and the volume of the landslide body is about 1.61 ×106 m3 . (2) According to the geological environment conditions of the landslide area, the stability of the landslide under two working conditions is calculated. Under the conditions of dead weight, the landslide is in a basically stable state; under the conditions of dead weight and heavy rain, the landslide is in an understable state. (3) By collecting the monitoring data of the automated surface displacement monitoring station, the deformation trend of the area where the GNSS01 and GNSS03 monitoring points are located in the landslide profile of Beiyaocun is obvious, with periodic characteristics and experiencing multiple step reduction. In addition, the fractures in this area are also in a continuous deformation stage. (4) This area has the topographic conditions for the formation of landslides. The rock and soil composed of slopes have low strength and are easy to soften when exposed to water. The structural plane is consistent with the slope direction, and the precipitation infiltration increases the sliding weight, decreases the anti-sliding force and increases the sliding force, which destroys the original stress balance of the slope and makes it easy to slip. [Conclusions] The slope deformation of Beiyao Village landslide is obvious, in which the foundation of buildings near the front is disturbed and most of them collapse. In addition, topography is the necessary condition for landslide formation, slope lithology is the material basis of landslide formation, and water plays a catalytic role in landslide formation and is an important inducement factor. The results of this study can provide reference for regional urbanization construction and development, and provide guidance for regional landslide disaster prevention.
Highlights: Based on the results of field geological survey and field drilling, the development and deformation characteristics of landslide in Beiyao Village are systematically studied, and the causes and influencing factors of landslide in the study area are discussed and analyzed according to the monitoring data of integrated monitoring equipment.
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This paper is the result of CO2 geological storage research.
[Objective] The geological storage of CO2 is an effective approach to address climate change, reduce CO2 emissions, achieve carbon neutrality, support environmental protection and energy resource security, as well as to promote the harmonious coexistence of economic development and ecological protection. [Methods] This study focuses on the Hepu Basin in Guangxi as the research unit. Based on the geological characteristics, the deep saline aquifer was identified as the geological reservoir. The D-level predicted geological potential during the reconnaissance phase was calculated using the mechanisms of residual trapping and solubility trapping. Seven primary indicators and sixteen secondary evaluation indicators were selected to conduct the suitability assessment for CO2 geological storage.[Results]The results indicate that the D-level predicted geological potential for CO2 storage in the saline aquifer of the Hepu Basin is 189.01×10⁶ . The suitability evaluation results for the two assessment units, Xichang Depression and Changle Depression in the Nanliujiang Depression, are "moderately suitable". [Conclusions] The evaluation results provide a scientific basis for the preliminary site selection for CO2 geological storage project construction in Guangxi.
Highlights:On the basis of sorting out the geological background conditions, the D-level predictive geological potential for carbon dioxide in saline aquifers during the exploration phase was calculated using the mechanisms of trapped storage and dissolved storage. A comprehensive evaluation system was established, comprising 7 primary indicators and 16 secondary evaluation indicators, for assessing the suitability of CO2 geological storage. This provides a scientific basis for the preliminary site selection of CO2 geological storage engineering construction in Guangxi, and holds significant practical guiding value.
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This paper is the study of soil selenium and enrichment factors. [Objective] The spatial variation of selenium in the soils of Xiaoertai Town, Zhangbei County, is significant, with some areas exhibiting clear surface enrichment. Identifying selenium sources and enrichment factors is crucial for the future development and utilization of selenium-rich land resources. [Methods] This study analyzed the soil geochemistry data of Xiaoertai Town, Zhangbei County, using correlation analysis, variance analysis, and GIS spatial analysis methods to explore selenium content, spatial distribution, and enrichment factors. [Results] The results showed that the content of Se in the topsoil of Xiaoertai Town was 0.17 mg / kg), which was higher than that of the background soil (0.15 mg / kg). The area with selenium content above the natural enrichment standard (≥0.3 mg/ kg) accounted for 8% of the study area. Selenium-enriched soils were mainly found in areas along developed river systems and low-lying zones on either side of the rivers. Factors such as parent material, soil type, and land use influenced selenium content and enrichment levels. Correlation analysis revealed a significant negative correlation between selenium and pH, and a significant positive correlation with organic carbon. [Conclusions]This study provides valuable insights for the development and utilization of selenium-rich land in Zhangbei County.
Highlights:For the first time, the geochemical characteristics of soil selenium in the study area were systematically summarized, and the sources of soil selenium were preliminarily determined based on the parent material and relevant geological background. Possible factors affecting soil selenium enrichment were analyzed from multiple aspects such as soil type, land use type, and soil physicochemical properties.
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