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Journal of Geoscience and Environment Protection 2024年第9期12卷 388-406页

作者： Tekoum Leontine Benadjingar Nguelmbaye Jean Claude Doumnang Mbaigane Laboratoire de geologie geomorphologie et de teledetection Département de Géologie Faculté de Sciences Exactes et Appliquées Université de N’Djaména N’Djamena Chad Laboratoire hydro-géosciences et reservoirs Département de Géologie Faculté de Sciences Exactes et Appliquées Université de N’Djaména N’Djamena Chad

Water is an essential element for all forms of life. The quantity and quality of water are a problem in places. In Kouba Adougoul and its surroundings in south guera, water-related health problems are reported. That is why this study focuses on the quality of water in the basement areas, of Kouba Adougoul. Our objective is to contribute to a better understanding of water of human consumption in these areas for this, we carried out a physicochemical and bacteriological control on a number water point. Ten water points were collected during May 2022 for analysis. To achieve this objective, we made the in-situ analysis of physical parameters such as pH, electrical conductivity, and temperature. These measurements were made using the multi-parameter kit. The result shows that, the water temperatures vary from 24.4˚C to 27.4˚C proving that the waters are from deep depths. For the use of these waters, it is necessary to take certain precautions. The pH values varied between 6.15 and 7.78, an average of 6.77 giving some waters an aggressive character. It was low mineralized, with electrical conductivity averages ranging from 182.1 to 2100 μS/cm − 1 an average of 586.36 μS/cm − 1 . For the chemical parameters, it is by hydrometric titration that the content of the ions was determined. The determination of the various coliforms in these waters was carried out by its various methods which led to detecting that the waters of Kouba Adougoul are turbid, and present high proportions of nitrates, iron and ammonium. The presence of pathogenic germs, such as total coliforms and thermo-tolerant coliforms in these waters, has been demonstrated. For their consumption, these waters deserve treatment beforehand. In the study area, the anthropogenic activities are considered the most serious sources of groundwater.

关键词： Environmental Pollution Hydrochemistry Aquifers crystalline basement Kouba-Adougoul (Guera-Chad)

Forming Proterozoic basement within eastern Central Asian Orogenic Belt:Evidence from zircon U-Pb-Hf-O isotopes

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Journal of Central South University 2022年第9期29卷 3088-3105页

作者： WANG Zhi-wei ZHU Tai-chang YU Jing-wen YUAN Ling-ling Hebei Key Laboratory of Strategic Critical Mineral Resources Hebei GEO UniversityShijiazhuang 050031China Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring(Ministry of Education) School of Geoscience and Info-PhysicsCentral South UniversityChangsha 410083China College of Earth Sciences Hebei GEO UniversityShijiazhuang 050031China

As part of the mosaic of micro-continents within the Central Asian Orogenic Belt(CAOB), the Xing’anAirgin Sum Block(XAB) features increasingly-recognized Meso-Neoproterozoic geological records. However, the origin, temporal-spatial distribution of ancient materials, and their roles in crust evolution remain to debate. This paper presents an integrated study of zircon U-Pb ages and Hf-O isotopes for Mesoproterozoic and Paleozoic granites from the Erenhot region of central Inner Mongolia, along eastern CAOB. The intrusion of 1450 Ma syenogranite denotes that the Precambrian basement of XAB extends from Sonid Zuoqi westward to Erenhot. The 384 and 281 Ma monzogranites containing Mesoproterozoic xenocrystic zircons possess Proterozoic-dominant two-stage Hf model ages, further suggesting the wide existence of Proterozoic crust beneath western XAB. Cyclic Proterozoic crustal growth and reworking seem to show close linkages with the orogenesis during relevant supercontinent cycles. 1450-1360 Ma juvenile crustal growth at Erenhot and synchronous ancient crust reworking at Sonid Zuoqi and Abagaqi were likely resulted from retreating subduction involved in Columbia breakup, while 1.2-1.0 Ga reworking and 0.9-0.7 Ga growth events within the Erenhot basement might respond to assembly and breakup of Rodinia, respectively. Besides, our work confirms that reworking of Neoproterozoic crust played important roles during Paleozoic multi-stage accretion of CAOB.

关键词： Proterozoic Central Asian Orogenic Belt Xing’an-Airgin Sum Block crystalline basement granitoids zircon U-Pb-Hf-O isotopes

Identification of major sources controlling groundwater geochemistry in Mount Makabaï in the Far-North of Cameroon(the northernmost part of the Pan-African Belt)

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Acta Geochimica 2023年第2期42卷 266-289页

作者： Merlin GountiéDedzo DésiréTsozué Amidou Kpoumié Aubin Nzeugang Nzeukou Department of Life and Earth Sciences Higher Teachers’Training CollegeUniversity of MarouaP.O.Box.55MarouaCameroon Department of Earth Sciences Faculty of ScienceUniversity of MarouaP.O.Box.814MarouaCameroon

The present work focuses on the volcanic basement rock geochemistry of Mount Makabaï(MarouaCameroon city)in relation to groundwater *** were centered on an approach involving an association of several methods such as geological cartography,hydrogeology,and *** rock samples,four disturbed soil samples,three undisturbed soil samples,and 20 samples of groundwater in 10 wells were collected during fieldwork and prepared for laboratory *** exhibit porphyritic,aphyric,and subaphiric *** phenocryst phases are mainly olivine,clinopyroxene,and *** on whole rock major element chemical compositions,the Makabaï samples,plotted on Na_(2)O+K_(2)O versus SiO_(2)diagram,are mugearite,hawaiite,and *** ratio of(MgO+CaO)/(Na_(2)O+K_(2)O)exceeds unity and shows dominance of alkaline Earth metals(MgO:2.99-4.48%;CaO:6.19-9.80%)relatively to alkali metals(Na_(2)O:2.27-4.46%;K_(2)O:2.09-2.51%).Exchangeable base contents are high,mostly represented by Ca and Mg,whose contents vary from 14.6 to 35.28 cmol(+)kg^(-1)and from 3.28 to9.48 cmol(+)kg^(-1)*** CECclayis likewise high,fluctuating between 116.80 and181.38 cmol(+)kg^(-1),values in line with the presence of 2:1 clay minerals represented in the study area by *** the water samples,the Ca2+and Na+contents are generally higher than K^(+)and Mg^(2+),reflecting the relative abundance of Na_(2)O and CaO oxides to K_(2)O and MgO oxides in rocks where different waters were *** waters of Makabaï are acidic to neutral(6.3≤pH≤7.4)and weakly to highly mineralized(110.0≤EC≤1190.0μS/cm).Hydro-geochemical classification by using the Piper diagram revealed two water types:(1)CaMg-HCO_(3)(40%)and(2)CaMg-Cl or CaMg-SO4(60%).The average content of ions in all the analyzed samples was HCO_(3)^(-)>>NO_(3)^(-)>SO_(4)^(2-)>Cl-for anions and Ca^(2+)>>Mg^(2+)>Na^(+)>K^(+)for *** mechanisms governing ionic constituents of groundwater in

关键词： Mount Makabaï-Maroua city Far-North Cameroon Bedrock minerals Groundwater-rock-soil interaction crystalline basement

Geochemical and Nd-Hf Isotopic Constraints on the Petrogenesis of an Archean Granitoid in the Erguna Massif, NE China

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Acta Geologica Sinica(English Edition) 2021年第6期95卷 2033-2044页

作者： SHAO Jun LI Yinglei WANG Deli SONG Wanbing WU Xinwei LIU Hongzhang Shenyang Institute of Geology and Mineral Resources Shenyang CenterChina Geological SurveyShenyang 110034China Key Laboratory of Orogen and Crust Evolution Department of GeologyPeking UniversityBeijing 100871China Institute of Mineral Resources Chinese Academy of Geological SciencesBeijing 100037China Inner Mongolia 115th Geological Mineral Exploration and Development Co.Ltd. Huhhot 137100China Inner Mongolia 6th Geological Mineral Exploration and Development Co.Ltd. HulunbuirInner Mongolia 021008China Hebei Regional Geological Survey Institute Hebei 065000China

crystalline basement and Precambrian crustal growth of the continental massifs within the Central Asian Orogenic Belt(CAOB) are still pending problems. Our geological and geochemical investigations identified an Archean(2606 Ma) granitic pluton in the Biliya area of the Erguna Massif. The Neoarchean granitoids show high and positive in-situ zircon ε_(Ht)(t)(+0.3 to +10.0), whole-rock ε_(Nd)(t)(+4.8) and whole-rock ε_(Ht)(t) values(+2.1). They are characterized by high Y + Ce + Zr + Nb(> 220 ppm) and Zr contents and could be classified as A-type granites. These granitoids are characterized by high Zr saturation temperatures(T;)(796–836°C). They were derived from partial re-melting of juvenile mafic lower crust in an intracontinental back-arc extensional environment. This newly identified Neoarchean granitic pluton may represent the crystalline basement of the several continent massifs within the CAOB, and their high ε_(Ht)(t)–ε_(Nd)(t) values may also indicate the occurrence of lateral crustal growth events in these massifs during the Neoarchean.

关键词： crystalline basement A-type granite Neoarchean crustal growth Neoarchean Central Asian Orogenic Belt

Characteristic of Gravity and Magnetic Anomalies in the Daba Shan and the Sichuan basin, China: Implication for Architecture of the Daba Shan

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Acta Geologica Sinica(English Edition) 2013年第4期87卷 1154-1161页

作者： ZHANG Jisheng GAO Rui LI Qiusheng GUAN Ye WANG Haiyan LI Wenhui Institute of geology Chinese academy of geological sciences Earthprobe and geodynamics open laboratory Ministry of land and resources

The Dabashan nappe structural belt links the Hannan block to the west with the Huangling block to the east between Yangxian and Xiangfan. The Dabashan arc-shaped fold belt formed during late Jurassic and was superposed on earlier Triassic folds. To achieve an improved understanding of the deep tectonics of the Dabashan nappe structural belt, we processed and interpreted the gravity and magnetic data for this area using new deep reflection seismic and other geophysical data as constraints. The results show that the Sichuan basin and Daba Mountains lie between the Longmenshan and Wulingshan gravity gradient belts. The positive magnetic anomalies around Nanchong-Tongjiang-Wanyuan-Langao and around Shizhu result from the crystalline basement. Modeling of the gravity and magnetic anomalies in the Daba Mountains and the Sichuan basin shows that the crystalline basement around Nanchong-Tongjiang-Wanyuan-Langao extends to the northeast underneath the Wafangdian fault near Ziyang. The magnetic field boundary in the Zhenba-Wanyuan-Chengkou-Zhenping area is the major boundary of the Dabashan nappe thrusting above the Sichuan Basin. This boundary might be the demarcation between the south Dabashan and the north Dabashan structural elements. The low gravity anomaly between Tongjiang and Chengkou might be partly caused by thickened lower crust. The local low gravity anomaly to the south of Chengkou-Wanyuan might result from Mesozoic strata of low density in the Dabashan foreland depression area.

关键词： Daba Mountains nappe structural belt Sichuan basin gravity anomaly magneticanomaly crystalline basement

Study on the basement structure in the southeastern North China by blasting seismic

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Geodesy and Geodynamics 2018年第4期9卷 312-319页

作者： Zhenyu Fan Jinren Zhao Suzhen Pan Cejun Ma Mingxin Qu Yan Hai Xiaoguo Deng Geophysical Exploration Center of China Earthquake Administration Zhengzhou 450002 China

Since the Mesozoic, southeastern North China Craton has experienced intense crustal thinning and lithosphere destruction. Some of the responses of the deep activity in the upper crust crystalline basement have been retained in a series of tectonic evolution. The study of the upper crust velocity structure,especially the properties of the basement interface, is of great significance for studying the tectonic evolution and seismic hazard in the southeastern part of North China. In this study, we selected Pg waves of the blasting seismic data in the southeastern part of North China in recent years, which reflect the west Shandong uplift, offshore sedimentary basins and the Tanlu Fault zone and the Sulu orogenic transition zone, to study the structural and seismological characteristics of basement in North China Craton. The results of this study showed as follows: First, the obvious lag of Pg wave arrival time in Dongying depression and North Jiangsu basin reveals the thick sedimentary, low velocity and unstable basement structure. Second, the advance Pg wave arrival time with high apparent velocity, which reflects the basement structure of the west Shandong uplift, indicates the thin sediments and the shallow basement. Third, combined with many geophysical phenomena, such as electrical structure, density structure and terrestrial heat flow, we hold that the Tanlu tectonic belt and the Sulu orogenic belt have experienced great lithosphere destruction and there is shallow crust and the thinnest lithosphere in the vicinity of the Tanlu fault zone.

关键词： Blasting seismic detection Southeastern North China crystalline basement Pg arrival time