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Source of metals related to gold occurrences in Cameroon, Central African Belt

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Acta Geochimica 2024年第2期43卷 308-324页

作者： Kevin Igor Azeuda Ndonfack Jinlin Zhang Yuling Xie NSamiratou Yaya Emmanuel Archelaus Afanga Basua JCHX Mining Management Co. LtdBeijing 101500People’s Republic of China Institute of Geology Chinese Academy of Geological SciencesBeijing 100037People’s Republic of China School of Civil and Environmental Engineering University of Science and Technology BeijingBeijing 100083People’s Republic of China Department of Earth Science University of BamendaBamendaRepublic of Cameroon

Suites of granitic and metamorphic rocks form a perfect geological environment in which to investigate the source of metals related to gold *** the East Province of Cameroon,the source of metals-related gold(grade~4.6 g/t)that occurs within metamorphic and granitic rocks remains *** host rocks were subjected to XRF and ICP-MS whole-rock geochemistry and BSE/EDS mineral analyses to investigate the source(s)of metals related to gold in the ***,chalcopyrite-pyrite and magnetite-ilmenite are the main sulfi des and oxides of granites,*** low-grade metamorphic rocks are sulfi de-rich consisting of arsenopyrite,chalcopyrite,pyrite,and sphalerite,and oxides include magnetite,ilmenite,hematite,and ***,Ni,Co,Sb,Sc,and Zn concentrations depleted in high-grade metamorphic rocks and granites compared to low-grade metamorphic *** well,Bi,Cd,Co,Cu,Ni,Sb,V,W,and Zn concentrations decrease with increasing temperatures from low-grade rocks to high-grade rocks and *** suite of depleted elements in high-grade rocks and granites is almost identical to those enriched in gold *** conclude that metals(Bi,Cd,Co,Cu,Ni,Sb,and Zn)related to gold mineralization in the East Province of Cameroon likely originated from metal-rich low-grade metamorphic rocks during prograde metamorphic processes prior to partial melting.

关键词： East Province of Cameroon metamorphic rocks Granites Oxide–sulﬁdes Metal and gold Geochemistry

Reservoir Characteristics and Controlling Factors of the metamorphic Buried Hill of Bozhong Sag, Bohai Bay Basin

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Journal of Earth Science 2021年第4期32卷 919-926页

作者： Yong’an Xue Meng Zhao Xiaojian Liu China National Offshore Oil Corporation Tianjin BranchTianjin 300459China

The burial depth of the metamorphic buried hill of the Bozhong sag is more than 4500 m,however,the controlling factors of the reservoirs are not *** on cores and sidewall cores obtained from 15 wells,this paper describes the reservoir characteristics and discussed their controlling *** metamorphic basement of the Bozhong sag consists of metamorphic granite,migmatitic granite and *** felsic rocks are more likely to develop fractures,thereby improving the reservoir *** Indosinian,Yanshanian and Himalayan tectonic events greatly reformed the Bozhong 19-6 metamorphic buried hill,forming a large scale fracture *** and deep thermal fluid contributed to the development of dissolved pores of the *** general,controlled by lithology,tectonics,weathering and deep thermal fluid,the reservoir pattern of the metamorphic buried hill of the Bozhong 19-6 structure was established.

关键词： metamorphic rocks buried hill Bozhong sag Bohai Bay Basin

metamorphic Evolution and Tectonic Implications of Garnet–Bearing Mica Schist in Sumdo High Pressure Belt from Eastern Lhasa Block, Tibet

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Acta Geologica Sinica(English Edition) 2015年第A2期89卷 3-4页

作者： CHEN Mei YANG Jingsui ZHANG Cong TIAN Zuolin HUANG Jie YU-Huanglu DONG Tianci School of Earth Science and Mineral Resources China University of Geosciences Beijing 100083 China State Key Laboratory for Continental Tectonics and Dynamics Institute of Geology Chinese Academy of GeologicalSciences Beijing 100037 China MOE Key Laboratory of Orogenic Belts and Crustal Evolution School of Earth and Space Sciences Peking UniversityBeijing 100871 China

The garnet-bearing mica-quartz schist of the Sumdo high pressure metamorphic beltfrom the Lhasa block is mainly composed of garnet, muscovite, albite, quartz and minor chlorite, rutile and sphene.

关键词： RESEARCH metamorphic rocks Muscovite Mica Chlorite minerals Garnet Schists

Pressure-temperature Evolution of the Metapelites in the Motuo Area, the Eastern Himalayan Syntaxis

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Acta Geologica Sinica(English Edition) 2014年第2期88卷 544-557页

作者： DONG Hanwen XU Zhiqin LI Yuan LIU Zhao State Key Laboratory of Continental Tectonics and Dynamics Institute of GeologyChinese Academy of Geological Sciences China University of Geosciences

The Motuo area is located in the east of the Eastern Himalayan *** outcrops a sequence of high-grade metamorphic rocks,such as *** and mineralogy data suggest that these rocks have experienced three stages of *** prograde metamorphic mineral assemblages （M1） are mineral inclusions （biotite ＋ plagioclase ＋ quartz ± sillimanite ± Fe-Ti oxides） preserved in garnet porphyroblasts,and the peak metamorphic assemblages （M2） are represented by garnet with the lowest Xsps values and the lowest XFe# ratios and the matrix minerals （plagioclase ＋ quartz ± K-feldspar ＋ biotite ＋ muscovite ＋ kyanite ± siilimanite）,whereas the retrograde assemblages （M3） are composed of biotite ＋ plagioclase ＋ quartz symplectites rimming the garnet *** computation shows that the metamorphic conditions are 562-714℃ at 7.3-7.4 kbar for the M1 stage,661-800℃ at 9.4-11.6 kbar for the M2 stage,and 579-713℃ at 5.5-6.6 kbar for the M3 *** rocks are deciphered to have undergone metamorphism characterized by clockwise P-T paths involving nearly isothermal decompression （ITD） segments,which is inferred to be related to the collision of the India and Eurasia plates.

关键词： metamorphic rocks P-T path Motuo area the Eastern Himalayan Syntaxis

Pressure-Temperature Evolution of a Mylonitic Gneiss from the Lower Seve Nappe in the Handol Area,Central Sweden

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Journal of Earth Science 2021年第6期32卷 1496-1511页

作者： Botao Li Hans-Joachim Massonne Xiaoping Yuan School of Earth Sciences China University of GeosciencesWuhan430074China Fakultät Chemie Universität Stuttgart70569StuttgartGermany

Ultrahigh-pressure metamorphism has recently been reported from various crustal rocks in the Seve Nappe Complex(SNC)in which microdiamonds were ***,in gneiss from the Lower Seve Nappe(LSN),neither any direct petrographic indication for UHP was reported nor the metamorphic evolution was well *** studied a mylonitic gneiss from the Handol area of the LSN and applied phase-diagram modeling and Ti-in-biotite *** on the compositions of garnet and biotite and observed mineral assemblages,a path was reconstructed passing through about 8 kbar and 730℃at prograde ***-pressure and initial retrograde stages occurred at 9.0–10.2 kbar at 745-775℃,and 7–9 kbar atmetamorphic rocks of the LSN,a possible interpretation is that slices or erased blocks were subducted,metamorphosed at different depths,and exhumed in a subduction ***,the dominant gneiss of the SNC experienced only a medium-pressure metamorphism in the upper part of the downgoing Baltica *** from different depth levels were brought together in an exhumation channel located between Baltica and the overlying plate.

关键词： Lower Seve Nappe Swedish Caledonides mylonitic gneiss P-T pseudosection modeling Ti-in-biotite thermometry metamorphic rocks

Modelling of Distribution Pattern of Rare Earth Elements in Grey Gneisses and Their Petrogenesis of Dabie Complex

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Journal of Rare Earths 1993年第2期11卷 148-151页

作者：王江海 Institute of Geochemistry Academia SinicaGuiyang 550002China

The grey gneisses are composed of early-stage layered TTG and late-stage diapiric tonalite intrusions. The Dabie complex, northeastern Hubei Province, may be distinguished into supracrustal sequence and grey gneisses. Different distribution patterns of rare earth elements in the early- and late-stage gneisses, i.e. the early-stage gneisses are enriched in LREE and remarkably depleted in HREE; and late-stage is slightly enriched in LREE and unevidently depleted in HREE. Geological evidence and characteristics of element ratio diagrams suggest that the TTG is mainly controlled by portional partial melting and accompanied with fractional crystallization. The quantitative modelling of REE pattern indicates that TTG is formed from amphibolite transformed from basic rocks with 25% to approximately 65% of portional partial melt while the late-stage tonalite intrusion was also accompanied with fractional crystallization of 22% biotites.

关键词： Crystallization Geochemistry Geologic models Geology Melting metamorphic rocks Petrology

GEOCHEMISTRY OF PRE-MESOZOIC GOLDBEARING FORMATIONS IN SHAOXINGLONGQUAN UPLIFT REGION, ZHEJIANG PROVINCE

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Science in China,Ser.B 1988年第8期31卷 994-1009页

作者：刘英俊孙承辕沙鹏 Department of Geology Nanjing University

The geochemistry of the main country rocks of gold deposits in Shaoxing-Longquan uplift region has been systematically studied in this paper. The authors believe that the Proternzoic Shuangxiwu group is the primary gold-bearing formation in this region and the Sinian-Cambrian Chencai group and the Precambrian Zuoxi migmatized quartz-diorite are the derivative gold-bearing formations. The genesis of rocks, content distribution features of gold and silver, characteristics of associated trace elements and other geochemical features in these formations clearly show a relationship of inheritance with evolution. By means of metamorphic-solution and volcanic-solution or/and other geological actions, these gold-bearing formations supplied the necessary ore-forming materials for the gold deposits in this region.

关键词： geochemistry gold metamorphic rocks Zhejiang Province.

Jade in the Serpentinite Mélanges of the Rio San Juan Complex from the Dominican Republic

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Acta Geologica Sinica(English Edition) 2015年第A2期89卷 79-80页

作者： SCHERTL Hans-Peter MARESCH Walter V. HERTWIG Andreas Institute of Geology Mineralogy and GeophysicsRuhr-University Bochum

New occurrences of jadeitite, jadeite quartzites, and jadeite-lawsonitequartzites have recently been discovered in the Rio San Juan Complex （RSJC） of the northern Dominican Republic. These rocks are found in serpentinite mé1anges associated with a former intra-oceanic subduction zone （Fig. 1）. The mé1anges contain blocks of various high-pressure （HP） metamorphic rock types such as blueschist, eclogite, jadeitite, orthogneiss, rare cymritebearing rocks, marble and metapelite.

关键词： RESEARCH metamorphic rocks Petrology Serpentinite Jade Melanges (Petrology)

Diamonds and the Kokchetav Massif

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Acta Geologica Sinica(English Edition) 2015年第A2期89卷 81-83页

作者： Schertl Hans-Peter Institute of Geology Mineralogy and GeophysicsRuhr-University Bochum

A geodynamical revolution in modern geosciences was initiated by Chopin （1984） and Smith （1984）, who discovered metamorphic coesite in rocks of the Dora Maira Massif, Italy and the Western gneiss region, Norway, r... 详细信息

关键词： DIAMONDS RESEARCH ULTRAHIGH pressure metamorphism metamorphic rocks ECLOGITE AMPHIBOLITES CRUST of the earth