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The geology and Geochemistry of Porphyrite Iron Deposits in the Nanjing-Wuhu area,Southeast China

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Chinese Journal Of Geochemistry 1990年第1期9卷 1-26页

作者：李文达匡福祥 Nanjing Institute of geology and Mineral Resources Ministry of Geology and Mineral ResourcesNanjingChina

For the iron deposits occurring in andesitic volcaic rocks of the Lower Yangtze *** genetic model for porphyrite iron deposits was proposed by chinese geologists more than ten years ago on the basis of their detailed studies in the Nanjing-Wuhu *** comprises a set of deposits of different genetic types ranging from late magmatic segregation ,ore-magma injection,pneumato-hydatogenetic replacing and hydrothermal filling as well as sedimentary *** deposits are closely connected with the gabbro-diorite porphyrite subvolcanic intrusive bodies both in space and in ***4alization and wall-rock alteration are consistent with the history of the magmatic *** studies on trace elements and S,O,Sr isotopes have proved that the porphyrite iron deposits are of magmatic origin,The proposed model may be applied to iron ores associated with andesitic volcanites,for example,in Chile,Mexico,Pakistan,Turkey,etc.

关键词：地球化学玢岩铁矿床硫同位素锶同位素氧同位素南京地区武汉地区

Solar cycles during the seventeenth century revealed by equatorial aurora records

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Earth and Planetary Physics 2025年第1期9卷 182-187页

作者： Yong Wei LiMei Yan Key Laboratory of Earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China

Solar cycles are fundamental to astrophysics,space exploration,technological infrastructure,and Earth's climate.A better understanding of these cycles and their history can aid in risk mitigation on Earth,while also deepening our knowledge of stellar physics and solar system *** the solar cycles between 1600 and 1700-especially the post-1645 Maunder Minimum,characterized by significantly reduced solar activity-poses challenges to existing solar activity *** study utilizes a new red equatorial auroral catalog from ancient Korean texts to establish solar cycle patterns from 1623 to ***,a further reevaluation of the solar cycles between 1610 and 1755 identified a total of 13 cycles,diverging from the widely accepted record of 12 cycles during that *** research enhances our understanding of historical solar activity,and underscores the importance of integrating diverse historical sources into modern analyses.

关键词： solar cycle Maunder Minimum solar activity red equatorial aurora West Pacific geomagnetic anomaly

Economic geology Study with Focus on Cu Mineralization (Fath Abad area, Khorasan Razavi)

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Journal of Geoscience and Environment Protection 2016年第10期4卷 1-27页

作者： Reza Ehsani Naghmeh Mohamadi Mohamd Hossain Ehsani geology Department Islamic Azad University of Tehran North Branch Tehran Iran

The study area is located in south of Khorasan-Razavi province. This region is part of central Iran, which is of high significance due to existence of metal and non-metal deposits. Considering the location of the study area, the lithology and metal-mineral indices of Dolat-Abad sheet, it can be said that their metallic deposits are economically feasible. Hence, this region is considered promising for exploration of metallic deposits. In order to achieve this goal, at first, the region’s alterations were detected by using OLI-ASTER images in ENVI software. After processing the lithogeochemical data in SPSS and GIS software, anomaly map of studied elements was obtained. Using geological map, different layers such as lithology, faults and indices were obtained. Eventually, by preparing the layers and incorporating those using the index overlay GIS modeling, promising mineralization areas in the region were identified. Results show that a significant Cu-Au mineralization has occurred in the south western region of the study area.

关键词： Fath-Abad Khorasan-Razavi Copper Geochemical Remote Sensing

geology and Mineral Chemistry of Gold Mineralization in Mirge-Naqshineh Occurrence(Saqez,NW Iran):Implications for Transportation and Precipitation of Gold

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Acta Geologica Sinica(English Edition) 2018年第1期92卷 210-224页

作者： Golale ASGHARI Samad ALIPOUR Hossein AZIZI Hassan MIRNEJAD Department of geology Urmia University Mining Department Faculty of Engineering University of Kurdistan Department of geology Faculty of Science University of Tehran

The Mirge-Naqshineh gold district is situated at northwest of Iran with a NW-trending brittle- ductile shear zone. It is hosted by Precambrian meta-sedimentary and meta-volcanic units traversed by mineralized quartz veins. In terms of cross-cutting relationships and sulfide content three types of quartz veins are identified in the region. Among those, parallel to bedding quartz vein （type I） is the main host for gold mineralization. Gold is found in three different forms： 1） submicrometer-size inclusions of gold in arsenian pyrite, 2） as electrum and 3） in the crystal lattice of sulfides （pyrite, galena and chalcopyrite）. Six types of pyrite （Pyl-Py6） were identified in this ore reserve. Py3 coexists with arsenopyrite and contains the greatest As-Au concentrations. There is a negative correlation between the As and S contents in Py2 and Py3, implying the substitution of sulfur by arsenic. Pyrites and mineralized quartz veins were formed via metamorphic-hydrothermal fluid and reflect the gold-transportation as Au（HS）2 under reducing and acidic conditions. The gold precipitation mainly controlled by crystallization of arsenian pyrite during fluid/rock interactions and variation offO2. The volcanic host rock has played an important role in gold concentration, as Py3 in this rock contains inclusion of gold particles, but gold is within the lattice of pyrite in phyllite or other units.

关键词： gold quartz veins mineral chemistry EPMA Mirge-Naqshineh Iran

An investigation on the wind profiles and gravity wave dynamics in MLT region based on the meteor radars from the Meridian Project

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Earth and Planetary Physics 2025年第1期9卷 29-38页

作者： Tai Liu Zhe Wang MengXi Shi Willie Soon ShiCan Qiu Department of Geophysics College of the Geology Engineering and GeomaticsChang’an UniversityXi’an 710054China Center for Environmental Research and Earth Sciences(CERES) SalemMA 01970USA Institute of Earth Physics and Space Science(ELKH EPSS) 9400SopronHungary

The meteor radar can detect the zenith angle,azimuth,radial velocity,and altitude of meteor trails so that one can invert the wind profiles in the mesosphere and low thermosphere(MLT)region,based on the Interferometric and Doppler *** this paper,the horizontal wind field,gravity wave(GW)disturbance variance,and GW fluxes are analyzed through the meteor radar observation from 2012−2022,at Mohe(53.5°N,122.4°E)and Zuoling(30.5°N,114.6°E)stations of the(Chinese)Meridian *** Lomb−Scargle periodogram method has been utilized to analyze the periodic variations for time series with observational data *** results show that the zonal winds at both stations are eastward dominated,while the meridional winds are southward *** variance of GW disturbances in the zonal and meridional directions increases gradually with height,and there is a strong pattern of annual *** zonal momentum flux of GW changes little with height,showing weak annual *** meridional GW flux varies gradually from northward to southward with height,and the annual periodicity is *** both stations,the maximum values of zonal and meridional wind occur close to the peak heights of GW flux,with opposite *** observational evidence is consistent with the filtering *** horizontal wind velocity,GW flux,and disturbance variance of the GW at Mohe are overall smaller than those at Zuoling,indicating weaker activities in the MLT at *** power spectral density(PSD)calculated by the Lomb−Scargle periodogram shows that there are 12-month period and 6-month period in horizontal wind field,GW disturbance variance and GW flux at both stations,and especially there is also a 4-month cycle in the disturbance *** PSD of the 12-month and 6-month cycles exhibits maximum values below 88 km and above 94 km.

关键词： meteor radar wind field gravity wave Lomb−Scargle method

geology of the Structurally Controlled Quartz Vein Gold Mineralization in the Dikko area, Part of Zungeru—Minna—Birnin Gwari Schist Belt, NW Nigeria

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Journal of Geoscience and Environment Protection 2021年第7期9卷 180-191页

作者： Abdullahi Adamu Mohammed Adamu Usman Mohammed Otorison Abdulganiu Danladi Abubakar Sadiq Applied geology Department Abubakar Tafawa Balewa University Bauchi Nigeria geology Department (Engineering Services) Federal Capital Development Authority (FCDA) Abuja Nigeria Hadejia Jama’are River Basin Development Authority Kano Nigeria

Dikko area, Niger State, North Central Nigeria falls within the Pan-African thermo-tectonic event which occurred in Nigeria as in other parts of West Africa with widespread effect on the mineralization of rejuvenated basement and geosynclinal trough deposits. The Pan-African Belt in Nigeria forms part of the Benin-Nigeria (Dahomeyan) shield which is regarded as the southern prolongation of the circumcratonic Pan-African belt of the West African Craton. Structurally controlled, gold-bearing quartz veins were measured and studied in the area from an extensive geological ground investigation. Field and petrographical studies indicate that the Neoproterozoic rocks constitute gneisses, amphibolite schist, amphibolites and migmatites. The amphibolites are intruded by pegmatites. The associated quartz veins are generally concordant with the main N-S regional structural trend. The lithological and structural studies carried out in these areas have demonstrated the relationship between structures and mineralization and/or lithology. The main characteristics of the gold mineralization in the area appear to indicate hydrothermal mineralization in connection with shear zones. This study allows us to predict that quartz veins in the amphibolite can be mined at a profit and a detailed geochemical and resource valuation needs to be carried out for the Au and associated Galena and Ag mineralization to fully exploit their economic potential.

关键词： Gold Mineralization Quartz Veins Pan-African Economic Potential Mined

A Study of the U-Pb Isotopic Systematics and Its APplication in Uranium geology

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Acta Geochimica 1984年第2期3卷 142-153页

作者：周维勋夏毓亮 Beijing Institute of Uranium geology Changsha Institute of Uranium geology

The main purpose of this paper is to present a fundamental concept of U-Pb isotopicspectrum-system and its application to the interpretation of the mechanism of uranium ore *** is evident from a number of examples of uranium deposits that uranium depositsformed in various processes are characterized by different types of U-Pb isotopic spectrum-system.

关键词： A Study of the U-Pb Isotopic Systematics and Its APplication in Uranium geology Pb

Investigation of geology and Hydro-geophysical Features Using Electromagnetic and Vertical Sounding Methods for Abu Zabad area,Western Kordofan State,Sudan

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Journal of Environmental & Earth Sciences 2020年第1期2卷 1-6页

作者： Elhag A.B Musa M.A. Department of Civil Engineering College of EngineeringKing Khalid UniversityAbhaSaudi Arabiaon leave from Kordofan UniversitySudan Department of geology College of Science and Information TechnologyNyala UniversityNyalaSudan

The geology and hydro-geophysical features can aid in identifying borehole *** study aims to investigate groundwater aquifers and best location of boreholes in the crystalline basement area of Abu Zabad near El Obeid Southwest,*** study area is underlain by two aquifers formations from Precambrian *** oldest units of basement complex of area under investigation consist of metamorphic rocks including gneiss,schist,and *** geophysical methods electromagnetic(EM)and vertical electrical sounding(VES)surveys showed that best aquifers yield for construction of boreholes are in weathering and fractures *** EM results revealed that structural features are significant for groundwater potential and interpretation of the VES data also revealed four geo-electric layers,but generally two distinct lithologic layers,which include Superficial deposit and bedrock-basement *** curves generated from the data revealed H curve and HK curve,and thickness of these layers varies from 15 m to 50 m in the *** aquifer thickness range from 20 m to 30 *** study concludes that these techniques are suitable for identifying borehole location in the basement rock in Abu Zabad area Sudan.

关键词： Electromagnetic and geoelectric survey Aquifer units and groundwater potential

Structural geology and Chronology of Shear Zones along the Shangdan Suture in Qinling Orogenic Belt,China:Implications for Late Mesozoic Intra-Continental Deformation of East Asia

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Journal of Earth Science 2024年第2期35卷 376-393页

作者： Falak Sheir Wei Li Le Zhang Basil Alabowsh Liuqing Jiang Li Liang Sainan Gao Shair Baz Umar Ashraf State Key Laboratory of Continental Dynamics Department of GeologyNorthwest UniversityXi’an710069China Institute of geology University of PunjabLahore45590Pakistan

The Shangdan suture zone(SDZ)in the Qinling orogenic belt(QOB)is a key to understanding the East Asia tectonic *** SDZ gives information about convergent processes between the North China Block(NCB)and South China Block(SCB).In the Late Mesozoic,several shear zones evolved along the SDZ boundary that helps us comprehend the collisional deformation between the NCB and SCB,which was neglected in previous *** shear zones play an essential role in the tectonic evolution of the East Asia *** study focuses on the deformation and geochronology of two shear zones distributed along the SDZ,identified in the Shaliangzi and Maanqiao *** shear sense indicators and kinematic vorticity numbers(0.54–0.90)suggest these shear zones have sinistral shear and sub-simple shear deformation *** quartz’s dynamic recrystallization and c-axis fabric analysis in the Maanqiao shear zone(MSZ)revealed that the MSZ experienced deformation under green-schist facies conditions at∼400–500℃.The Shaliangzi shear zone deformed under amphibolite facies at∼500–700℃.The^(40)Ar/^(39)Ar(muscovite-biotite)dating of samples provided a plateau age of 121–123 *** with previously published data,our results concluded that QOB was dominated by compressional tectonics during the Late Early ***,we suggested that the Siberian Block moved back to the south and Lhasa-Qiantang-Indochina Block to the north,which promoted intra-continental compressional tectonics.

关键词： Qinling orogenic belt Shangdan suture zone shear zone Late Mesozoic intra-continental deformation East Asia tectonics