矿物岩石地球化学通报
设为主页
加入收藏
Quick Search
Home
|
About Journal
|
Editorial Board
|
Instruction
|
Subscribe
|
Contacts Us
|
中文
Journal
Forthcoming Articles
Current Issue
Archive
Online before printed
Quick Search
Adv Search
Bulletin of Mineralogy, Petrology and Geochemistry
2018, Vol.37 Num.2
Online: 2018-03-10
1
2018 Vol. 37 (2): 1-1 [
Abstract
] (
227
) [
HTML
1KB] [
PDF
422KB] (
1275
)
157
SHEN Jun-feng, LI Sheng-rong, DU Bai-song, WANG Dong-li, LIU Hai-ming, PENG Zi-dong, BO Hai-jun, LI Ke, LIU Sheng-qiang
Minerals Alteration and Typomorph in Gold Deposit and Their Implications for Prospecting
Most of gold mineralizations are related to hydrothermal fluid activity. During the migration and evolution of the fluids in the ore-forming process, fluid would extensively reacted with wall rocks and precipitated gold at suitable tectonic space,resulting in alteration minerals in the pathways. Such alteration minerals were formed under certain conditions so that their association could be used to represented the changing of physical-chemical condition during mineralization and be used as prospecting vector. Therefore, all characteristics of mineral formed in the process for identifying ore-forming condition are called mineral typomorph. In terms of mineralization alteration and its spatial distribution related to gold mineralization, and typical mineral properities (such as thermoelectricity of gold-bearing pyrite, short wave infrared spectroscopy and magnetic susptibility of altered minerals, and so on), mineral zonation and alteration mapping can establish mineralization and exploration models. These models could be useful for further ore prospecting. In this study, we compared the characteristics of mineral alteration and typomorph in some gold deposits. The results suggest that typomorph-based mineral mapping is a power tool for lessening target area and ore prospecting.
2018 Vol. 37 (2): 157-167 [
Abstract
] (
396
) [
HTML
1KB] [
PDF
2826KB] (
1662
)
168
YANG Zhi-jun, HUANG Shan-shan, CHEN Yao-ming, LEI Xue-ying, LI Xiao-xiao, ZENG Xuan
Characteristics and Their Geological Significances of Spinel Minerals of Kimberlite in Mengyin, Shandong Province
Spinel minerals, as a group of accessory minerals in kimberlite, were formed throughout the whole evolution process of kimberlite. The morphological and compositional characteristics of spinel minerals can be effectively used to decipher the evolution process of kimberlite magma. In order to figure out characteristics of spinel minerals of kimberlite in Mengyin, Shandong Province, those samples were observed and analyzed by using optic microscope, electron microprobe analysis (EMPA), scanning electron microscope (SEM) and LA-ICP-MS for their appearance characteristics and mineral compositions. The results show that spinel minerals in matrix of the Mengyin kimberlite generally are 20~60μm sized euhedral crystals with zoning texture. They are thought to be primary spinel. From the core to the edge of the zoning spinel minerals, the Cr contents are gradually decreased, whereas the Ti contents and Fe
2+
/(Fe
2+
+Mg) values are gradually increased. Based on their morphologies, there are enhedral-subhedral crystals and atoll grains of spinel minerals. The various zonings of the spinel could be caused by various factors including the thermal interference of the environment, variations of the pressure and melt composition. These difference characteristics of spinel minerals in the Mengyin kimberlite indicate that the kimberlite had experienced a long term complex evolution process.
2018 Vol. 37 (2): 168-179 [
Abstract
] (
436
) [
HTML
1KB] [
PDF
8326KB] (
928
)
180
JIN Run-cheng, LI Guo-wu, LUO Zhong-lie, JIN Yin-he, ZHAO Yong-yan
Study on Temperature-Pressure Conditions of Brucite Formation in Wolsa Marble, North Korea
In this study, we attempted to use the mineral composition of the newly discovered brucite-bearing marble from the Wolsa district to constrain the temperature-pressure conditions of brucite formation. Mineral composition was performed by petrography, XRD, chemical, and thermal analyses on brucite-bearing marble. In terms of mineral compositions, the reaction equation forming brucite was established and the thermodynamic model was evaluated. The brucite-bearing marble is composed of 30.33% of brucite, 10.51% of dolomite, 56.66% of calcite and a small amount of periclase. Brucite is a hydration product of periclase and appears as a typical fibrous aggregate. Thermodynamic modeling indicates that the decomposition of dolomite to periclase is gradually formed under low temperature (426-550℃) and low pressure (<2.6 MPa), in the shallow region close to the surface during long-term geological process.
2018 Vol. 37 (2): 180-185 [
Abstract
] (
316
) [
HTML
1KB] [
PDF
2319KB] (
517
)
186
LI Guo-wu, XUE Yuan, XIE Ying-mei
Mineralogical Characteristics and Genesis of New Mineral Tewite
Tewite is a new mineral that discovered in the Panzhihua-Xichang region in 2014. It is associated with scheelite, tellurite and two of unnamed new minerals with compositions of KW
2.27
Al
0.33
O
9
(submitted to IMA-CNMNC as 2017-067a) and WO
3,
respectively. How this mineral association was formed is a matter of concern. In this study, we explored the origin of tewite by field investigation, crystal chemistry (Electron probe, infrared spectrum, X-ray powder-diffraction), and synthetic method. Although tewite occurred in Neoproterozoic monzonite, such unique mineral is not likely to result from crystallization from Neoproterozoic medium-felsic magma but was formed in the vein-type gold mineralization related to Permian mafic magmatism. Te is highly enriched in volcanism/magmatism-related hydrothermal fluids that is Te-W-rich. Such fluids reacted with potassium feldspar in the monzonite following the process of KAlSi
3
O
8
+TeO
2
+WO
3
K
2
Te
2
W
5
O
19
+SiO
2
, resulting in the formation of tewite. This reaction has been proved by our synthetic experiment. Finnally, tewite filled the fractures in monzonite after alteration.
2018 Vol. 37 (2): 186-191 [
Abstract
] (
353
) [
HTML
1KB] [
PDF
2063KB] (
514
)
192
MENG Fan-cong, TIAN Guang-kuo, DUAN Xue-peng, FAN Ya-zhou, REN Yu-feng
Evidence from Garnet for Genesis of Garnet-Cordierite-Granite in the Jinshuikou Area, Eastern Segment of the East Kunlun Mountains
In order to constrain the tectonic setting and genesis of the garnet -cordierite-granite in the Jinshuikou area, eastern segment of the East Kunlun Mountains, petrography and mineral chemistry of the garnet has been studied in this paper. There are two types of garnet in the granite:magmatic and peritectic. The former granet is rare and usually associated with quartz and feldspar. This type of garnet occurs as fine-grained, euhedral to subhedral crystal without mineral inclusions. It is enriched in MnO and poor in MgO, with MnO compositional zoning. The latter is bigger in size, and xenomorphic, containing minerals inclusions. It is poor in MnO and enriched in MgO, without MnO composition zoning. This type of garnet is abundant and commonly associated with biotite. The coexistence of the two type garnets indicates that the granite formed through anatexis or migmatization, indicating that the the Jinshuikou area has experienced decompression and heating processes in the Early Paleozoic.
2018 Vol. 37 (2): 192-204 [
Abstract
] (
375
) [
HTML
1KB] [
PDF
4374KB] (
640
)
205
ZHANG Ju-quan, WANG Ji-zhong, LI Sheng-rong, SHEN Jun-feng, LU Jing
Genetic Mineralogy Analysis on the Mineralization Process of Skarn Iron Deposit in Han-Xing Area, Southern Taihang Mountains
In this study, genetic mineralogy analysis has been used to constrain the origin of skarn type iron deposits in the Han-Xing area. Composition, structure and age of identified minerals in the magmatic-hydrothermal system were used to discuss the controlling factors of Fe enrichment in ore-forming process, and establish the metallogenetic model of such iron deposits. Results showed that there are two types of magma evolution processes in this area, forming two individual metallogenic systems. In the hornblende diorite-diorite metallogenic system, high-Mg diorite and Fe-rich ore-forming fluid were formed by fractional crystallization of magnesium-rich amphibole at high oxygen fugacity condition. But in diorite-monzonite metallogenic system, 2.5 Ga iron-rich metamorphic basement was assimilated into the magma, and provided countable mineralization material. Reaction between oxidized hydrothermal fluids and Ca-rich carbonate would form Fe-rich skarn, such as andradite, consuming large amounts of Fe so that the fulids would be Fe poor and be unfavorable in Fe mineralization. When ore-forming fluids reacted with Mg-rich carbonate, Fe-poor skarn, such as diopside, would not significant lower Fe in fluids. Such fluids would remain Fe-rich and form iron deposits.
2018 Vol. 37 (2): 205-213 [
Abstract
] (
325
) [
HTML
1KB] [
PDF
4991KB] (
523
)
214
LUO Zhao-hua, GUO Jing, HEI Hui-xin, WANG Bing-zhang, WANG Tao
Plagioclase Crystal Populations of the Granodiorite in the Jiaqi-style Porphyry Cu-Mo Deposit, Eastern Kunlun Orogen, Qinghai, and their Metallogenic Implications
In recent years, more and more researchers accept the opinion that igneous rocks are composed of crystal populations. In this article, taking the granodiorite in the Jiaqi-style porphyry Cu-Mo deposit, Eastern Kunlun orogen, as an example, we attempt to clarify the content of the term "crystal population", and indroduce the methodology and implications for studying crystal populations. The petrography and CL images indicate that plagioclase grains in the granodiorite can be subdivided into five types. Chemical variation across the plagioclase crystal grains by EMPA further suggests that these five types of crystals have crystallized in different conditions and processes so that they are of different crystal populations. According to principles of the equilibrium thermodynamics, the five crystal populations are likely to be derived from five different magma subsystems, which suggests that the parental magmas are the product of magma mixing of a multiple chamber system. The mixing magmas must have experienced a quickly solidification process. The new insights are important for revealing origin of the porphyry deposits.
2018 Vol. 37 (2): 214-228 [
Abstract
] (
386
) [
HTML
1KB] [
PDF
3966KB] (
512
)
229
QING Min, HAN Xian-ju, ZHANG Le-jun, ZHANG Dai, ZHAO Yu-suo, XIAO Li, WANG Ke-yong
Trace Element Characteristics of Pyrites from the Jinchang Gold Deposit in Helongjiang Province, China and Its Geological Significance
This paper carried on in situ LA-ICPMS trace element analysis and elemental mapping on pyrite from four metallogenic stages in breccia-pipe type and fault-controlled altered rock type gold mineralization, in the Jinchang super-large gold deposit, Dongning County, Heilongjiang Province, China. The results show that pyrite is rich in As, Co, Ni, Cu, Pb, Zn, Au, Ag, Sb, Se, Te and Bi and with small amounts of W, Mo and Sn. From the first metallogenic stage to the fourth, pyrites from two types of gold mineralization have covariant trace metal element compositions with overall trend of decreasing Co, Ni and increasing As. Enrichment of Au, Ag, Cu, Pb and Zn concentrated in the second and third stages. It is thus concluded that two gold mineralization types and three gold orebodies of Jinchang belong to different part of the same porphyry system. The content of As, Au+Ag, Cu, Pb+Zn, total trace elements and compositional zonation in pyrite can be effective indicators to evaluate intensity of gold (polymetallic) mineralization, associated ore-forming elements and ore occurrence. Elemental mapping of pyrite using LA-ICPMS can effectively and economically distinguish different stages pyrite and easily qualify the variety of trace elements.
2018 Vol. 37 (2): 229-241 [
Abstract
] (
425
) [
HTML
1KB] [
PDF
5941KB] (
547
)
242
LI Jie, ZHANG Jing, YIN Lu
Advances and Problems of Re-Os Isotope Analysis of Geological Samples
Over the past twenty years, with the development of analytical technology, Re-Os isotopic system has become one of the most powerful tools in isotope geochemistry. Compared with other traditional lithophile isotopic systems, both Re and Os are siderophile, chalcophile and organophilic elements. Therefore, Re-Os isotopic system can be directly used in dating metal sulphides, ultramafic rocks, and organic-rich rocks. Although wide applications of Re-Os isotope in dating and tracing, there also have some difficulties in Re-Os isotope analysis. This study here has a brief review and comparison of these issues in terms of the total procedural blank, sample digestion techniques and mafic rock reference materials.
2018 Vol. 37 (2): 242-249 [
Abstract
] (
370
) [
HTML
1KB] [
PDF
2328KB] (
649
)
250
LEI Chuan-yang, WU Jian-liang, YIN Xian-ke, LIU Wen, WANG Bo, LI Wei, YUAN Hua-yun, ZHANG Wei, YIN Tao, PEI Ya-lun
New Discovery of the Diorite Porphyry Dyke in the Shamuluo Formation in Western Segment of the Bangongco—Nujiang Suture Zone and Its Geological Significance
In order to discuss the genesis and tectonic setting of the diorite porphyry dyke in the Shamuluo Formation in the western segment of the Bangongco-Nujiang suture zone,and to further discuss their significances to the regional tectonic evolution, the chronology and geochemistry of the diorite porphyry dyke have been undertaken in this paper. The results indicate that the diorite porphyry is characterized with features of a metaluminous,high-potassium and calc-alkaline I-type granitoid,with a LA-ICP-MS zircon U-Pb dating age of(103.5±1.5)Ma and the medium differentiation. The chondrite-normalized REE patterns are generally right-declined patterns which are characterized with steep in left and flat in rightand intermediate negative Eu anomalies. The primitive mantle-normalized trace element spider diagrams show that it is relatively enriched in large ion lithophile elements,such as Rb, K,Th, Zr, Hf, U, and is depleted in high field strength element,such as Ba, Nb,P and Ti. With the combination of regional geological background, it is suggested that the diorite porphyry could be formed in the continental arc setting resulted fromof the northward subduction of the Bangongco-Nujiang Tethyan Ocean.The magma was mainly derived from the partial melting of lower crust which was caused by the underplating of the mantle magma derived from the metasomatized mantle wedge by subducted sediments. It is believed that the Bangongco-Nujiang oceanic plate was still northward subducting to the Qiangtang plate in late stage of the early Cretaceous approximately at(103.5±1.5)Ma.
2018 Vol. 37 (2): 250-259 [
Abstract
] (
410
) [
HTML
1KB] [
PDF
3672KB] (
581
)
260
LV Zheng-hang, ZHANG Hui, TANG Yong, ZHAO Jing-yu, LIU Yun-long, GUO Liu
The Distribution of Phosphorous in Various Types of Pegmatites from Altai, Xinjiang and Its Implication
The Xinjiang Altai is an important area of rare metal resources which are going to be exhausted because of the long-term exploitation and the limitation of traditional geophysical methods for prospecting rare metal ore deposits. Thus, it is urgently required to innovate exploration method and make breakthrough in exploration of rare metal resources. Previous studies suggest that prealuminous rocks with mineralization of rare metal are commonly characterized with high P content. The analyses of P
2
O
5
contents in alkaline feldspars from four types of pegmatites by using EPMA and the statistics on P contents in pegmatites have been conducted in this work, in order to verify the prospecting indicators proposed by previous studies and outline prospecting target. The results demonstrate that the barren pegmatites are characterized with low P contents (P
2
O
5
<0.1%), whereas the mineralized pegmatites are characterized with high P contents (P
2
O
5
≥ 0.1%). Therefore, this work supports that the P
2
O
5
>0.1% of alkaline feldspar is an effective indicator for prospecting rare metal ore deposits of pegmatite. It is noticed that P contents of the Permian mineralized pegmatites are generally lower than those of the Triassic mineralized pegmatites, we suggest that the Permian pegmatites have relatively low potential for finding rare metal resources. As the Triassic pegmatites in the Halong-Qinghe subzone commonly have high P contents, it is suggested that the rare metal exploration should be concentrated in a target area from the Keketuohai to the upstream of the Kalaeerqisi river in the Xinjiang Altai.
2018 Vol. 37 (2): 260-270 [
Abstract
] (
354
) [
HTML
1KB] [
PDF
2896KB] (
559
)
271
LIU Bin, WANG Xue-qiu
Origin of Cu Geochemical Deomains in the Middle-Lower Yangtze River Region and Its Constraints on the Formation of Cu Deposit Districts
In this paper, we analyze the genesisof large deposits/ore districts in the Middle-Lower Yangtze River region from the originof ore materials. Five copper geochemical domains in the study area were selected.All discovered Cu deposit concentration areasand most of the large Cu deposits are located within such geochemical domains. Combined with published Sr-Nd, Hf isotopeand zircons U-Pb age data of ore-forming rocks in the study area, we conclude that the large amount of Cu in the region was mainly derived from the enriched lithospheric mantle and a small amount addition of crustal material. These large-scale Cu rich domains can provide huge ore-forming materials for the Middle-Lower Yangtze River metallogenic belt, formingextensive copper mineralization after long-term tectonic activity andmagmatism.
2018 Vol. 37 (2): 271-282 [
Abstract
] (
385
) [
HTML
1KB] [
PDF
3808KB] (
974
)
283
WEI Qing, FAN Hong-rui, LAN Ting-guang, LIU Xuan
Hydrothermal Alteration and Element Migration in the Sizhuang Gold Deposit, Jiaodong Province, China
The Sizhuang gold deposit, located at the Zhaoyuan-Laizhou metallogenic belt in the northwestern border of the Jiaodong Peninsula, is a typical fracture-alteration type gold deposit. The gold mineralization is associated with typical diffusive K-feldspar alteration, sericitization, silicification and pyrite-sericite-quartz alteration at the hanging wall or the footwall of the main fault and near the ore bodies. During the fluid-rock interaction processes, the major and trace elements of altered rock were largely changed. LILE (Rb) and LREE (La and Ce) show variable degrees of mobility; TRTE (Cr, Co, Ni, and Cu) are strongly mobile; HREE and HFSE (Ta, Ti, Nb) can also be highly modified during the K-feldspar alteration. The gold in the Sizhuang gold deposit was most likely transported as Au(HS)
2-
complex. When the temperatures of ore-bearing fluid drops or the chemical properties of fluids continuously changed due to water-rock reactions, the stability of Au(HS)
2-
complex will be reduced, triggering gold precipitation.
2018 Vol. 37 (2): 283-293 [
Abstract
] (
335
) [
HTML
1KB] [
PDF
5322KB] (
554
)
294
XU Jing-chi, GU Xue-xiang, WANG Jia-lin, ZHANG Yong-mei, HE Ge, ZHOU Chao, LIU Rui-ping
Zircon U-Pb Geochronology, Geochemistry and Geological Significance of Granites from the Sanfengshan Cu-Au Deposit in Southern Beishan Orogenic Belt, Xinjiang
In this paper, we present the LA-ICP-MS U-Pb zircon dating and geochemical results for granites that exposed in the Sanfengshan Cu-Au deposit, to constrain their petrogenesis and tectonic setting, and the relationship between the magmatism and mineralization. The Sanfengshan granites mainly consist of monzo granite and granite aplite. Zircon LA-ICP-MS U-Pb age of the granites is 462 Ma (Middle Ordovician). The Sanfengshan granites mainly exhibit high K calc-alkaline and metaluminous to peraluminous characteristics, similar to those of I-type granites. They are enriched in Th, U, LREEs and large ion lithophile elements, and depleted in high field strength elements (Nb, P and Ti). In addition, the Sanfengshan granites are characterized by high contents of Sr, low concentrations of Y and Yb and high Sr/Y (31-108,>20), belonging to C-type adakites, indicating that parental magma of Sanfengshan is likely to result from partial melting of amphibolite eclogite at the bottom of thickened lower crust. It is suggested that the Sanfengshan granites were probably the product of island arc magmatism during the southward subduction of the Paleo-Asian Ocean beneath the Tarim Craton.
2018 Vol. 37 (2): 294-306 [
Abstract
] (
481
) [
HTML
1KB] [
PDF
5446KB] (
522
)
307
ZHAO Guo-bin, YANG He-qun, REN Hua-ning, XIE Xie, JIA Jian
The Cross-Range Mineral Exploration Guided by the Successive Evolution Regularity of Metallogenic Series—A Case Study of Copper Deposits Related to Ordovician Basic Volcanic-Sedimentary Rocks in the Shijuli Area, Northern Qilian Mountains
In order to more effectively guide mineral prospecting practices by applying the theory of metallogenic series, the relationships between metallogenic series and geological formations have been studied in this paper. It is believed that the same geological formation could contain syngenetic metallogenic series, pene-contemporaneous metallogenic series, epigenetic metallogenic series and supergene weathering metallogenic series. These several generations of metallogenic series which are related to the same geological formation have successive and evolutive relationship which can be used to guide cross-range mineral prospecting. Prospecting thinking is just opposite to the thinking of metallogenic process. In the mineral prospecting practice, based on the relevant element geochemical anomalies, we start to track supergene weathering metallogenic series firstly, then to subsequently track epigenetic metallogenic series, pene-contemporaneous metallogenic series and syngenetic metallogenic series. According to this prospecting thinking, the authors have summarized the experience for prospecting the Shijuli copper deposit which is related to Ordovician basic volcanic-sedimentary rocks in the northern Qilian metallogenic belt, and then have outlined two prospecting targets of Cu resources outside of the deposit in the belt.
2018 Vol. 37 (2): 307-315 [
Abstract
] (
472
) [
HTML
1KB] [
PDF
4275KB] (
873
)
316
LIU Bo, PENG Yun-biao, KANG Shi-hu, QIN Yan-wei
Depositional Characteristics and Uranium Metallogenic Fluid Dynamics of Uranium Bearing Paleo-valley of the Saihan Formation in Basaiqi, Erlian Basin
On the basis of borehole, seismic and well logging data, sedimentary characteristics, stratigraphic division of the Saihan Formation of basaiqi U-bearing paleo-valley at the Erlian Basin were carried out in this study. The lower member of the Saihan Formation mainly developed delta-lacustrine deposits which can be subdivided into two layers. the upper member of the Saihan Formation mainly developed alluvial fan-fluvial deposits that can be subdivided into 4 different layers. Different layers have experienced variable degrees of erosion in the top. Uranium mineralization is mainly hosted in the braided sandstone of first and second layers in the upper member of the Saihan Formation. Fluid dynamics of uranium mineralization indicates that there are two uranium mineralization patterns:(1) Reduction of U by reduced deep oil and gas within sandstons; (2) Mixing of oxidized U-bearing fluids of different salinities triggered the deposition of U. Through the study of stratigraphic division and metallogenic fluid dynamics, distribution of sandstone type uranium deposits in the paleo-valleys could be well constrained.
2018 Vol. 37 (2): 316-325 [
Abstract
] (
436
) [
HTML
1KB] [
PDF
4593KB] (
478
)
326
DING Kun, WANG Rui-ting, QIAN Zhuang-zhi, LUAN Yan, ZHANG Tian-yun, FENG Yan-qing, LI Yong-qin
Geochemical Characteristics of Trace Elements and Sulfur Isotopes of Sulfides from the Chenjiaba Cu-Pb-Zn Polymetallic Deposit, Lveyang County, Shaanxi Province
In order to explore the source of ore-forming materials and the genesis of the Chenjiaba Cu-Pb-Zn polymetallic deposit in the Mian-Lve-Yang ore-concentrated district, a geochemical study on REE, trace elements, and S isotopes of pyrite, chalcopyrite and sphalerite of the deposit has been carried out by using the ICP-MS and EA-IRMS instruments in this paper. The results show that the ore-forming elements, such as Cu, Pb, Zn, Ag, and Au etc. in pyrite are enriched comparing with the abundances of trace elements in the upper crust of the earth. It might reflect that the ore-forming elements were enriched in the ore-forming fluid. The Y/Ho ratios of pyrite (varying from 5.5 to 42) are similar to those of the quartz keratophyre, indicating the involvement of magmatic hydrothermal fluid in the mineralization. In addition, the pyrite has Co contents of 54.8×10
-6
-165.02×10
-6
and Co/Ni ratios ranging from 1.29 to 5.95, indicating that the deposit was formed in a medium to low temperature environment by the early volcanic exhalative mineralization and late hydrothermal mineralization. Sulfur isotopes of sulfides vary from 4.88‰ to 8.90‰, indicating that sulfur could be sourced from the mixture of the brine sulfate and sea water sulfate.
2018 Vol. 37 (2): 326-333 [
Abstract
] (
408
) [
HTML
1KB] [
PDF
3641KB] (
520
)
334
HUANG Kai-ping, ZHENG Mao-rong, SUN Ping-ming, CHEN Fang
Geochemical Characteristics of the Bahuang Uranium Deposit in the Eastern Guizhou and Their Constraints on the Sedimentary Environment of the Phosphorite
In order to reveal the genesis of the phosphorite-type uranium deposit, a geochemical study on the phosphorite hosted in the bottom part of the Jiumenchong Formation in the Bahuang uranium deposit in Eastern Guizhou has been conducted in this paper. The results show that the phosphorite is characterized with the enrichment of U, V, REE, Sr and Sb. The chondrite-normalized REE patterns of the phosphorite are featured with LREE enrichment right-inclined patterns with medium to weak negative Ce anomalies (δCe=0.30~0.81) and medium negative Eu anomalies (δEu=0.61~0.71).The low Th/U ratios (0~0.04) and highδU values (1.97~2.00) of the phosphorite indicate that it was formed in the anoxic reduction environment. The ratios of Fe/Ti, (Fe+Mn)/Ti and Al/(Al+Fe+Mn) of the phosphorite, varying from 54.24 to 121.5, from 55.35 to 123.7, and from 0.34 to 0.47, respectively, show both characteristics of the normal marine sedimentation and the submarine hydrothermal deposition. The high U/Th ratios (25.42~374.50) indicate that the source of U was probably associated with the submarine Sedex type hydrothermal activity. Therefore, It can be considered that the genesis of the Bahuang uranium deposit in Eastern Guizhou was related to the intermittent submarine Sedex type hydrothermal activity.
2018 Vol. 37 (2): 334-343 [
Abstract
] (
373
) [
HTML
1KB] [
PDF
3094KB] (
475
)
344
DING Wei, WANG Tao, LI Yan-bo, ZHANG Shuo
Petrogenesis of the Linshu Monzonitic Granite in the Southern Part of the Sulu Orogen
In order to discuss the age, type, source, tectonic environment and formation mechanism of the Linshu monzonitic granite pluton, which is tectonically occurred in the southern part of the Sulu orogenic belt, in Qingyun Town, Linshu County, the zircon U-Pb dating, petrology and elemental geochemistry of the rock have been undertaken in this study. The results show that the LA-ICP-MS zircon U-Pb age of the monzonitic granite is (126.6±3.8) Ma. The rocks are characterized with high Si, weak peraluminous, poor Fe and Mg, rich alkaline and high K, and low TFeO/MgO ratios. In addition, the rocks are depleted in HFSE including Nb, Ta, Ti, and P and relatively enriched in Pb and LILE including Rb, Th, K, and La, with highly differentiated REE distribution patterns which have moderate Eu negative anomalies (δEu=0.62-0.72). Therefore, it is believed that the rocks could be mainly derived from the partial melting of the lower crust of granulite facies under the moderate pressure (0.8-1.3 GPa), corresponding the depth of 35-45 km, in an extensional tectonic environment. In the diagenetic process, the mineral fractional crystallization could be occurred. The detachment of the lithosphere and the underplating of the mantle magma could be mainly resulted in the partial melting of the lower crustal material.
2018 Vol. 37 (2): 344-354 [
Abstract
] (
294
) [
HTML
1KB] [
PDF
3346KB] (
462
)
355
2018 Vol. 37 (2): 355-357 [
Abstract
] (
249
) [
HTML
1KB] [
PDF
2331KB] (
514
)
358
2018 Vol. 37 (2): 358-361 [
Abstract
] (
219
) [
HTML
1KB] [
PDF
2544KB] (
463
)
362
2018 Vol. 37 (2): 362-364 [
Abstract
] (
233
) [
HTML
1KB] [
PDF
3220KB] (
580
)
365
2018 Vol. 37 (2): 365-368 [
Abstract
] (
199
) [
HTML
1KB] [
PDF
2659KB] (
407
)
