Abstract:Abstract: The Wuling diorite stock was intruded in volcaniclastic rocks of the Carboniferous Dahalajunshan Formation. Iron ore deposits were discovered in the contact zone or the interior of the stock. Zircon LA-ICP-MS U-Pb dating of the diorite yielded a weighted mean 206Pb/238U age of （307.7±0.8）Ma. Positive εNd(t) values vary from3.1 to 4.6, initial 87Sr/86Sr ratios are relatively low (0.7043-0.7046), and Nd model ages vary between 695Ma and 818Ma and fall on the mantle trend line in the 87Sr/86Sr(t) versus εNd(t) diagram. These data indicate a mantle source for the Wuling diorite. However, high Th values (1.61-3.24μg/g) and Th/Ta ratios (6.1-7.9) imply that the magma experienced a certain degree of contamination by continental crust. Therefore, the Wuling diorite magma might have been formed by the fractional crystallization of basaltic magma affected by crustal material. Although some traces of arc magmatism can be detected, the Wuling dirote was actually formed by intraplate magmatism. This diorite was emplaced when block rotation occurred between the Yili and Tarim plates after the termination of the West Tianshan accretionary orogeny. It is inferred that the generation of the magma was probably related to the detachment of an orogenic root zone or a local squeezing-stretching structural transition zone within the Yili plate.

Abstract:Abstract: Located along the Aqishan-Yamansu belt of East Tianshan Mountains, the Shaquanzi Fe-Cu deposit is one of the deposits hosted in Paleozoic volcanic rocks. The deposit occurs in the second and third lithologic memberss of the Dikaner Formation consisting of volcanic rocks intercalated with sedimentary rocks. The iron mineralization also occurs at the contact zone between diorite-porphyrite and wall rocks. The tectonic setting and age of the volcanic rocks are key factors in the reconstruction of the ore-forming process. In this paper, representative samples of Dikaner Formation volcanic rocks and diorite-porphyrite in the Shaquanzi Fe-Cu ore district were analyzed for major and trace elements and zircon U-Pb dating was conducted to investigate the tectonic setting and formation ages of these rocks. LA-ICP-MS analyses of zircons with well-defined oscillatory zoning yielded mean 206Pb/238U ages of (321.7±1.7) Ma and (322.7±1.7) Ma, respectively, indicating that they were formed during late Early Carboniferous. The geochemical data suggest that most of the volcanic rocks belong to calc-alkaline series with the enrichment of LILE, LREE and depletion of Nb, Ta, and Ti, similar to the characteristics of arc volcanic rocks. The zircons from rhyolite and diorite-porphyrite have εHf(t) values of +6.28~+15.51 and ?0.22~+13.9, respectively. The rhyolites were derived from juvenile crustal materials and basalts, which came from mantle wedge modified by fluids from subducted materials that formed andesite and diorite-porphyrite through crystal fractionation. Regional geology and geochemical evidence indicates that the Dikaner Formation volcanic rocks and diorite-porphyrite were formed simultaneously through island arc magmatism during the late stage of subduction. The Shaquanzi Fe-Cu deposit hosted in the Dikaner Formation were formed after 322 Ma.

Abstract:Abstract: Located in the western part of the West Tianshan Awulale iron metallogenic belt, the Shikebutai iron deposit is a representative deposit in this belt. It mainly occurs in the Carboniferous Yishijilike Formation volcanic rocks dominated by tuff. Based onj rock geochemistry and LA-ICPMS zircon U-Pb dating of volcanic rocks in the Shikebutai iron deposit, this paper discusses the tectonic environment and petrogenic age of the volcanic rocks. Geochemical analysis shows that most of the volcanic rocks vary from high potassium calc-alkaline volcanic rocks to shoshonite series in chemical composition. The major elements indicate that volcanic rocks are mainly composed of andesite, dacite, rhyolite and dacite, belonging to calc-alkaline series. Trace elements and rare earth elements indicate that the tectonic environment for the formation of the volcanic rocks was active epicontinental volcanic arc. LA-ICPMS zircon U-Pb dating shows that 206Pb/238U weighted average ages of volcanic rocks are 301±1Ma and 313±2Ma, suggesting that volcanic rocks in this deposit were formed in early Late Carboniferous. Combined with regional geological data, the authors hold that the high-K calc-alkaline volcanic rocks of shoshonite series in the ore district may be the product of the late subduction of continental arc magmatism, and the tectonic environment for the formation of the volcanic rocks was active epicontinental arc. The chemical characteristics of the volcanic rocks are on the whole similar to features of Lower Carboniferous Dahalajunshan Formation volcanic rocks.

Abstract:Abstract: The Meishan polymetallic iron deposit is one of the representative deposits in Ningwu Basin, with its Fe-Cu-Au-Mo mineralization related closely with the gabbro-diorite porphyry. In this paper, the authors conducted LA-MC-ICP-MS zircon U-Pb dating of the ore-bearing gabbro-diorite porphyry and the fresh gabbro-diorite porphyry under the orebody, and obtained the U?Pb ages of (137.8±1.7) Ma and (141.2±1.0) Ma, respectively, suggesting that the gabbro-diorite porphyry was formed in 138~141Ma, the accompanying Fe-Cu-Au-Mo mineralization might have taken place later, and both occurred in Early Cretaceous, constrained by a tectonic regime extension and lithospheric thinning environment. Depending on the chronology and geological facts evidence, the authors put forward a new viewpoint that the volcanic-magmatism of Ningwu Basin began from the north and lasted for 7~10 Ma at least. The U-Pb ages of the older zircons from the gabbro-diorite porphyry range from 1903 to 1898 Ma, 1163 Ma and 296 to 292 Ma, suggesting Paleoproterozoic, Neoproterozoic and Early Permian. These data imply that the basement rocks made some contribution to the magmatism and there existed the so-called double layer structure of the Paleoproterozoic crystalline basement plus the Mesoproterozoic-Neoproterozoic fold basement in the Middle-Lower Yangtze River valley metallogenic belt (YRB).

Abstract:Abstract: Rhenium and osmium isotopes in a molybdenite sample and ten pyrite samples were used to determine the timing of mineralization by ICP-MS. Re-Os model age of the molybdenite sample is （2376±37）Ma, Re-Os ages of the ten pyrite samples yielded three kinds of ages : ① （2567±36）Ma—（2540±37）Ma (model age); ② （2237±112）Ma (model dating); ③ （1572±140）Ma (isochron age). These data suggest that the molybdenite of（2376±37）Ma was formed during early Proterozoic, and was the oldest Re-Os model age of molybdenite, the pyrite of（2237±112）Ma was formed during early Proterozoic, and both of them indicate that the molybdenite and the pyrite were derived from the crust and represented an important hydrothermal activity in 2.3 Ga; the pyrite of （2567±36）Ma—（2540±37）Ma was formed during new Archaeozoic period and yielded the oldest Re-Os model age, which indicates that the pyrite was formed with BIF in 2.5 Ga; the pyrite of（1572±140）Ma was formed during middle Proterozoic, which indicates that pyrite was derived from the crust and represented a hydrothermal activity. The Re-Os isotopic dating result provides a new proof for the existence of hydrothermal activity in iron deposits of the Anshan-Benxi area, and is also important for understanding the ore-forming processes and tectonic evolution in this area.

Abstract:Abstract: The Shikebutai iron deposit is hosted in Upper Carboniferous intermediate-acidic volcaniclastic rocks, low-grade metamorphic schist and phyllite in the Yili rifting of West Tianshan Mountains. Stratiform, stratoid and phacoidal orebodies are distributed along the strata. Ore minerals are predominantly hematite and specularite, with small amounts of pyrite and siderite, whereas gangue minerals are dominated by jasper, barite and quartz, with a small quantity of calcite. The ores display banded, lamellar and massive structures. Ore minerals usually show cryptocrystalline, filling and subhedral textures. The ore-forming process of the Shikebutai iron deposit can be divided into four stages, i.e., pyrite-hematite-jasper-barite stage, siderite-pyrolusite stage, quartz-specularite stage and oxide minerals stage. Geological characteristics of lamellar structure and the distribution along the strata indicate that the formation of the Shikebutai iron deposit was related to sedimentation. Electron microprobe analyses show that hematite from massive ore has variable Al2O3, Na2O, Mgo and SiO2 values, which suggests that massive hematite ores are products of rapid sedimentation and crystallization, and also implies the rapid extravasation of iron-rich fluids. Nevertheless, hematite from lamellar ore and banded ore have concentrated Al2O3, Na2O, Mgo and SiO2 values, suggesting that they formed in calm sedimentary environment with slow extravasation of iron-rich fluids. In general, the extravasation rate of mineral-rich fluid and the sedimentary environment changed continuously during the metallogenic process. The high Co-Ni ratio of pyrite shows that it was derived from volcanism. A negative correlativity between FeOT and MnO+MgO is found in siderite which can be divided into two groups corresponding respectively to two different types of siderite under microscope. These phenomena imply that siderite experienced a process of differentiation at the late metallogenic stage. The δ34S values of pyrite range from -6.1‰ to 6.5‰ and the value of barite is 12.9‰ , which indicates that the sulfur was derived from magma, and it was subjected to fractionation between sulfide and sulfate. In summary, the Shikebutai iron deposit belongs to submarine volcanic exhalative-sedimentary high-grade iron deposit.

Abstract:Abstract: The Tiemulike iron deposit is one of the deposits with highest-grade magnetite in the Awulale metallogenic belt and is hosted in volcanic rocks of the Carboniferous Dahalajunshan Formation. Its wall rocks have experienced a little alteration, mainly chloritization and epidotization. According to the ore fabrics and microscopic observation, mineralization of the deposit can be divided into four ore-forming stages. Since very insufficient work has been done in this aspect, the genesis of the deposit fails to reach an agreement. Magnetite and hematite electron microprobe analyses show that the deposit was genetically closely related to the magmatic-hydrothermal system. Pyroxene and amphibole electron microprobe analyses show that alteration of pyroxene is very weak, with only slight actinolitization of hornblende. Sulfur isotope from pyrite (0.1‰~2.9‰) indicates that the metallogenic material might have been derived from deep mantle. Oxygen isotope from magnetie (-2.7‰~0.5 ‰) shows that late epithermal ore-forming process played an important role in the reformation of the early magnetite. Combined with the geological characteristics of the metallogenic belt, this paper suggests that the Tiemulike iron deposit was mainly formed by the magmatic-hydrothermal mineralization system; after the formation of a large quantity of magnetite, the remaining small amount of fluid was mixed with ocean water, resulting in a epithermal alteration process and leading to the filling of hematite and in the magnetite ore.

Abstract:Abstract: The Zhangjiawa skarn iron deposit with high-grade iron is located in Laiwu of Shandong Province within southeastern North China Craton. The Laiwu hydrothermal metasomatic iron deposit is located at the unconformity between Carboniferous Benxi Formation and Ordovician Majiagou Formation and near the contact zone between Majiagou Formation and Late Yanshanian diorite, with the mineral reserves reaching a large-size deposit. Recent researches show that mineral compositions are somewhat different with the distance from the contact zone. The inner zone consists of calcium skarn minerals such as garnet, pyroxene, amphibole and episode, while the outer zone is composed of magnesium skarn minerals such as phlogopite and serpentine. The zoning structures of garnets and pyroxene in the Zhangjiawa iron deposit indicate that the ore-forming environment of the deposit changed gradually with the evolution of mineralization. The environment was somewhat reducing and acid at the beginning and, with the growth of silicate minerals and magnetite, became oxidative and alkaline. Finally, polymetallic sulfides crystallized and the environment became acid and reducing.

Abstract:Abstract: The Akexike Fe-Au deposit on the northern margin of the Junggar Basin occurs in the contact zone between volcanic rocks and tuffs of the Nanmingshui Formation. The orebodies are podiform, veined, and lenticular in form. The deposit has expereinced silicification, sericitization, chloritization, pyritization and carbonatization. Field evidence and petrographic analysis indicate two periods of metallogenesis: the volcanic-sedimentary period associated with the development of Fe mineralization and the hydrothermal period associated with Au mineralization. Liquid- and a few CO2- rich inclusions characterize the volcanic-sedimentary period, whereas CO2- and carbon (CH4 and C4H6)-rich inclusions characterize the hydrothermal period. Volcanic-sedimentary period had NaCl-H2O-CO2 fluids with moderate temperature (major Th of 180-320 ℃), low salinity (mainly 6-10 wt% NaCleq), and modereate to low density (0.59-0.98 g/cm3). Hydrothermal period has NaCl-H2O-CO2-CH4 fluids with moderate temperature (major Th of 220-320℃), low salinity ( mainly 2-10 wt% NaCleq), and moderate to low density (0.55-1.03 g/cm3). Stable isotope analysis of quartz yielded values of -129.9‰ to -97.9‰ for δD, 7.9‰ to 12.3‰ for δ18OSMOW, and -2.6‰ to 4.4‰ for δ18Ofluid, indicating that the ore-forming fluids were magmatic fluids mixed with seawater. δD, δ18OSMOW, and δ18Ofluid values of the hydrothermal period are -129.8‰--102.6‰, 11.2‰-16.1‰, and 3.1‰-7.4‰, respectively, indicating that the ore-forming fluids were metamorphic water mixed with deeply circulated meteoric water. Combined with geological characteristics and fluids composition, the authors hold that Au mineralization of hydrothermal period was closely associated with CO2-CH4 fluids.

Abstract:Abstract: Located in the middle of Eastern Tianshan Mountains, the large-size Yamansu iron deposit is hosted in Andesitic volcanic clastic rock or andesitic tuff of the Lower Carboniferous Yamansu Formation, with a lenticular marble beneath the main ore body. The ore bodies occur as lamellar stratoids and lenses, controlled by EW-striking faults and circular faults. Wall rock alteration is strong, including garnet skarn and complex skarn. Electeon microprobe analyses show that the end member of garnet is andradite(And) with an average content of 63.59%, grossularite(Gro) with an average content of 34.11%, almandite(Alm) and spessartine(Sps) with an average content of 4.44%. Components of garnet and pyroxene are And45.68~100Gro0.67~57.95(A1m+Sps)11~29.03, which indicates that characteristics of this skarn minerals are quite similar to those in calcic skarn from the major large iron deposits, suggesting that they probably resulted from skarnization; In the Ca+Al+Mn versus Ti+V discriminant diagram showing spot analyses of magnetite and hematite, almost all data from the Yamansu ore deposit fall into the region of the skarn type iron deposit. In addition, in the ternary plot of Ti02-Al203-Mg0 of magnetite, many data from the Yamansu ore deposit tend to be seated in the sedimentary metamorphogenic and contact meatasomatic region while less data drop into magmatic mafic-ultramafic region. These two diagrams may suggest that the formation mechanism of magnetite from this ore deposit may be similar to that of magnetite from skarn iron deposits. Combining the geological characteristics with the study of mineralogy, the authors hold that most samples through a process of hydrothermal metasomatism, it indicates that iron formation was related to magmatic hydrothermal metasomatism.

Abstract:Abstract: Located in the central eastern part of Liaoning Province, the Yanqianshan iron deposit is a typical iron deposit of this area. The authors studied the petrographic and mineralogical characteristics of the Yanqianshan iron deposit, and analyzed the major and trace element geochemical characteristics of the iron formation and rocks. The iron formation is mainly the banded iron formation (BIF) and contains a small amount of lump ore, with its roof and floor rock as well as orebody interbed being mainly Archean Anshan Group phyllite. Analyses of major elements show that the iron ore is mainly composed of SiO2 and iron oxides, with low Al2O3 content and high LOI. The trace element distribution curve of the ore is of the right-oblique type, with the enrichment of the highly incompatible elements and LILE. There is a significant positive Eu anomaly, which resulted from the mixture of the seafloor hydrothermal fluid (> 300℃) with the seawater. It is shown that the BIF formation of this area was closely related to the seafloor hydrothermal activity. The HREE are abundant in the BIF in this area, the Y / Ho ratios are greater than 26, and La and Eu have positive anomalies. Due to lack of terrigenous material, the authors infer that the BIF formed in shallow water with the depth greater than 200m, and the iron-rich hydrothermal fluids migrated to relatively shallow water area and then experienced oxidation and precipitation to form a stable banded structure. A-C-FM restoration of the original rock in combination with Zr/TiO2-Ni diagram shows that phyllite is a kind of metasedimentary rock, and Sm / Nd ratios also suggest the characteristics of sedimentary rocks. Th values vary from 7.9 to 22.5×10-6 with an average of 15.8×10-6, La values vary from 17.9 to 71.7×10-6 with an average of 38.4 ×10-6, the average of La / Sc ratios is 2.3, the average of Th / Sc ratios is 1.0, and the average of La / Th ratios is 2.4 in the phyllite of this area. These data suggest the continental island arc sedimentary characteristics. It is thus concluded that the metallogenic environment of the Yanqianshan iron deposit was a back-arc basin around the Archean craton.

Abstract:Abstract: This paper presents in situ microanalysis data of garnets form the Jinshandian iron skarn deposit, Hubei Province. Studies show that garnets from the Jinshandian iron skarn deposit can be divided into two stages, i.e., early Al-rich garnets mainly with grossular and grossular-andradite series, and late Fe-rich garnets dominated by andradite, with the variation implying the increase of the fluid oxidation. Compared with the early garnets, the late stage are rich in large ion lithophile elements and high field strength elements as well as REE. Early grossular shows typical HREE-enrichment and LREE-depletion features, while smaller fractionation between HREE and LREE characterizes grossular-andradite series. Total REE content, δEu and HREE/LREE fractionation degrees of Fe-rich garnet samples vary from sample to sample, and are even different in different parts of a single garnet grain, suggesting that the process of its formation was not stable, and fluid properties changed greatly, possibly due to the addition of evaporate minerals from the wall rocks. Garnet in situ microanalysis research also suggests that the evaporate minerals added into the Jinshandian skarn system had features of heterogeneity and periodicity.

Abstract:Abstract: The Meishan iron deposit is located in the northern Ningwu Basin of the Middle-Lower Yangtze River metallogenic belt, and occurs at the contact zone between the gabbro-diorite porphyry and the pyroxene andesite of the Late Cretaceous Dawangshan Formation. The garnets of the Meishan iron deposit are similar to those of skarn deposits in end member, classified as andradite-grossular series. Magnetite and hematite display the characteristics of both Kiruna-type and porphyry copper deposits. Hematite and siderite were formed by hydrothermal fluids, and the hematite has at least two types. Gabbro-diorite porphyry (host rocks), magnetite and apatite share similar chondrite-normalized REE distribution patterns, indicating the same source. Nevertheless, the gabbro-diorite porphyry fails to show Eu anomalies and possibly resulted from magmatic fractional crystallization with high oxygen fugacity. Negative Eu anomalies of magnetites and apatites might have resulted from the enrichment of Eu2+ in the albites during the process of albitization. Iron was extracted from Fe2+-rich silicate minerals and migrated into the ore-forming fluid due to albitization of the gabbro-diorite porphyry.

Abstract:Abstract: China has rich nickel resources and is also a country of much nickel resources consumption. The nickel deposits are composed of magmatic type, marine sedimentary type and weathering crust type in China. The formation epochs were from the Neoproterozoic to Cenozoic, with the Neoproterozoic and late Paleozoic being two peaks. The spatial distribution of nickel deposits is relatively concentrated: they are mainly distributed in Northwest, Southwest and Northeast China, frequently exhibiting clustered distribution. The continental margin breakup belt, the post-collision orogenic belt and the mantle plume are three important tectonic settings of the nickel deposits in China. In this paper, the authors divided the nickel deposits in China into 30 Grade-III nickel metallogenic belts on the basis of the Grade-III metallogenic belts, described briefly the spatial distribution characteristics, metallogenic regularity, metallogenic conditions and ore-forming features of the nickel deposits, summarized the main geological characteristics of six nickel metallogenic belts, which include East Tianshan, Gansu-Xinjiang Beishan, Longshoushan, central Jilin-Yanbian, Kang-Dian and southern margin of the Yangtze, and discussed the prospecting orientation for the nickel resources. It is held that the depth of the intrusion should be regarded as the favorable exploration target for the Ni sulfide deposit.

Abstract:Abstract: The Wutuan granitic pluton in southwestern Hunan is mainly composed of biotite monzogranite and dimicaceous monzogranite. U–Pb zircon dating of a biotite monzogranite sample was carried out, and analyses of 9 zircon grains yielded an average age of (220.5±4.4)Ma, which indicates that the granites were formed in middle Late Triassic. The rocks are silicon-high (SiO2=70.64%~75.32%, 72.33% on average), aluminum-rich (Al2O3=13.24%~16.37%, 14.47% on average), potassium-high (K2O=4.27%~6.66%, 5.10% on average) and alkali-moderate (Na2O+K2O=6.71%~8.46%, 7.65% on average) ones, with K2O/Na2O ratios being 1.54~5.34 (2.23 on average) and ASI value being 1.24 on average, thus belonging to ferric, high-K calc-alkaline series and shoshonite series perluminous granitoids. Ba, Nb, Sr, P and Ti are pronouncedly depleted, while Rb, (Th+U+K), (La+Ce), Nd, (Zr+Hf+Sm) and (Y+Yb+Lu) are comparatively concentrated. The rocks have low ΣREE values of 84.35~222.90μg/g (156.81μg/g on average), δEu values of 0.17~0.52 (0.39 on average), (La/Yb)N values of 1.81~17.12 (10.57 on average), ISr values of 0.71813~0.72110, εSr(t) values of 193.5~235.6, εNd(t) values of -9.78~-9.70 and t2DM ages of 1.78~1.79 Ga. The C/MF-A/MF diagram indicates that the granites were derived from mudstones and clastic rocks. Al2O3/TiO2 ratios of most strongly perluminous granite samples are less than 100. All these data point to S-type granitiods and suggest that the granites might have come mainly from acid rocks of the middle-upper crust. Trace element diagrams for discrimination of the structural environment show that the granites were formed in a post-collisional tectonic setting. According to the petrogenesis, the discrimination of structural environment and regional tectonic evolutional setting, the authors infer that the formation mechanism of the Wutuan pluton should be as follows: the thickening of the crust in Indosinian movement caused the rise of the temperature of the crust, and later the weakening of the stress in the post-collisional tectonic setting caused the melting of the middle-upper crust, with the magma emplaced in a relatively open environment. In addition, upwelling and heat transference of asthenosphere mantle might have played a certain role in the formation of granitic magma.

Abstract:Abstract: The bedded cherts in Raohe area of eastern Heilongjiang Province constitute a significant component of Mesozoic Wandashan orogenic ophiolitic melange. A new paleomagnetic investigation was carried out for a Triassic red chert sequence in the western part of the WOB, with totally 200 samples collected. The bedded cherts of Lower Triassic Dajiahe Formation in Wandashan Orogenic Belt (WOB) in eastern Heilongjiang Province have been partially or completely subjected to remagnetization. In combination with the data of tectonic evolution of Wandashan Orogenic Belt and micropaleontology, the authors hold that the time of remagnetization was Late Jurassic-Early Cretaceous, caused by the orogenic fluid related to the westward subduction of the Pacific Plate.

Abstract:Abstract: The western Ordos Basin and its adjacent areas, which belong to the west of north China plate, experienced a transformation process from passive continental margin to active continental margin. The transformation of tectonic attributes also led to the changes of the basin’s nature: the passive continental margin basin in the western Ordos was converted into back-arc basin during the period of Daping stage-Aijiashan stage. According to the study of lithofacies-palaeogeography in west Ordos Basin, 8 depositional facies can be recognized in the middle-late Ordovician period: shore, tidal flat, gentle slope, evaporative platform, open platform, shelf, slope and basin. The shelf could be classified into 3 sub-facies，i.e., carbonate shelf, clastic shelf and mixed carbonate-clastic shelf. A set of shelf carbonate rocks of clastic rocks was deposited in the western Ordos Basin during Daping stage-Darriwilian stage. Nevertheless, in the Aijiashan stage, Helanshan region subsided intensively and turned into a closed, black shale basin, with the influence of the Caledonian tectonic movement and the gradual seawater withdrawal from the Ordos Basin. It is therefore held that the black shale basin might have been an important depositional area of hydrocarbon source rocks in this stage.

Abstract:Abstract: Based on the sedimentary sequence characteristics of the typical sections in different facies zones in Guizhou and Guangxi, the authors recognized two obvious sea level fluctuations during the late Early Devonian period. On such a basis, the sedimentary sequences are divided into two third grade sequences（SQ1, SQ2）. The sequences （SQ1, SQ2）can be correlated regionally. In addition, the authors observed that the curve of δ13C from Lower Devonian Dale Formation in Xiangzhou of Guangxi is coincident with the curve of the regional sea level fluctuations. This study indicates that the geochemistry as well as the sequences was well controlled by the sea level changes.

Abstract:Abstract: The Qimantag metallogenic belt in the East Kunlun Mountains is characterized by a large variety of deposit types and metallic kinds, with skarn deposits being the typical type. Hence, this belt has become one of the hotspots among geologists. In recent years, the prospecting for porphyry copper molybdenum deposit has achieved new breakthroughs continually in this metallogenic belt. In Ketinghaer, to the east of this belt, a new porphyry copper molybdenum deposit was discovered in 2013. The strata in this area belong mainly to Paleoproterozoic Jinshuikou Group, and the main rocks are metamorphic rocks, such as gneiss and marble. The Variscan and Indosinian intermediate-acidic intrusive rocks are widely distributed in this area, with the Indosinian intrusive rocks being the host rocks; within the rock bodies, there are small porphyry mass and cryptoexplosion breccia. In addition, the NW-, NE-trending structures and multiple geophysical-geochemical anomalies are also distributed in this area. Through a comprehensive analysis of the above conditions including geological conditions, geophysical-geochemical anomalies, and characteristics of typical porphyry copper molybdenum deposits, the authors tentatively summed up the prospecting thinking for porphyry deposits. On such a basis, the prospecting work was carried out, which led to the breakthrough finally. And then, the authors summarized the prospecting thinking and methods for the Ketinghaer porphyry copper molybdenum deposit, and established a geological-geochemical-geophysical comprehensive model so as to provide the train of thought and orientation in search for the same type of deposits in this region.

Abstract:Abstract: The metallogenic model and prospecting criteria of sedimentary bauxite deposits in Central Guizhou-South Chongqing region are summarized as follows: Guangxi movement?took place at the end of the Silunian and Ziyun movement that occurred at the last stage of the?Devonian period, which might both have been in the crust-mantle interaction phase of the E’mei mantle plume evolution. The transportation of a large amount of materials and radiation energy from the?mantle plume to the crust led to the rise-and-fall movement of the earth’s crust. During this period, large area of the region ??was uplifted, leading to the formation of the long-term uplifted area. At the end of the Devonian, the pediplanation occured. In the Early Carboniferous Yanguanian period, the climate?was?humid and rainy. Exposed surface?rock in the Lower Paleozoic experienced laterization and calc-laterization. Laterite weathering crust with gibbsite provided sources for the sedimentary bauxite. In Xiuwen and Xifeng-Zunyi sedimentary areas, the bauxite-bearing rock series of Jiujialu Formation formed at the Early Carboniferous Datang Stage. Suiyang-Zheng’an-Daozhen sedimentary area deposited bauxite ore-bearing rock series of the Dazhuyuan Formation in the Maping period which, after the formation of the limestone of the Late Carboniferous Huanglong Formation, generated calc?laterization. As the deposition region formed different parent rocks containing gibbsite-laterite weathering crust, the deposited bauxite ore-bearing rock series have different chemical and mineral compositions.

Abstract:Abstract: As different geological bodies have different background values of metallogenetic elements, the ore deposit may be not distributed in the range of geochemical anomaly, and hence the anomaly might only reflect the background of the rock. Based on 1:200000 geochemical surveying data obtained in Zhangjiakou area, the authors calculated the anomaly thresholds of Cu, Zn, V, Ti and Ni elements. The results show that the geochemical anomaly based on traditional statistics is determined by the distribution area of basalt. That is to say, the range of geochemical anomaly is controlled by the lithology. According to the background value of different lithologies, the authors computed contrast values in comparison with geochemical data. The results show that this calculating way is not affected by lithology. This method can effectively delineate geochemical anomalies in low background value area. The contrast value method has good prospecting indicator significance.

Abstract:Abstract: The evaluation method for shale gas, which is a very important unconventional oil and gas resource, is different from that for conventional oil and gas resources. According to the accumulation mechanism and formation process, the volumetric method seems to be the best method for evaluating shale gas resources in consideration of research status in China. In this paper, based on the analysis of maturity of organic matter, depth, gas content, preservation condition, surface environment of shale of Wufeng-Longmaxi Formation in the Middle Yangtze region, in combination with the definition standard of shale gas by Ministry of Finance, the authors hold that the Enshi-Pengshui area is a favorable area for exploration and development. According to the volume method principle for computing the shale gas resources, the acreage, thickness and density of gas-bearing shale in this area are 5174 km2, 57 m, and 2.71 t/m3 respectively. In accordance with the conditional probability, the authors assigned conditional probabilities to uncertain parameters, which include such factors as organic carbon content, total porosity and gas saturation. Finally, the geological resources of shale gas in favorable areas of Wufeng-Longmaxi Formation are estimated to be at 5434.7×108 m3.

Abstract:Abstract: Located in the northwest of Zunhua City of Hebei Province, Tangquan is characterized by hilly landscape and rich geothermal resources. In this paper, the authors studied the borehole data of many bedrock thermal wells (water wells) in the study area, and investigated the distribution characteristics and controlling factors of the geothermal field. The results show that borehole temperature is significantly affected by groundwater flow, and the vast majority of temperature wells are characterized by convective heat transfer, with a few temperature wells characterized dominantly by heat transfer conduction. The geothermal anomaly center of the study area is located in the area from Tangquan Fuquan Palace to the sanatorium, and the anomaly center exhibits bipolar distribution; the temperature of water at the depth of 50m in the geothermal anomaly center is about 51~54°C, and that at the depth of 100m is up to 60~67°C. The geothermal water of the geothermal system is caused by gradual heating action of surrounding rocks under the normal heat flow background in the process of deep circulation of groundwater. The water storage structure from Fuquan Palace to the sanitarium is formed by a buried basin with granite confining floor. Because faults cut through monolithic granite body, and cause the upward migration of the heat flux of the deep rock along the fault, whereas the heat flux is mixed with fissure water of the gneisses and is concentrated in the area from Fuquan Palace to the sanatorium. Because the gneiss fractures the aquifer in Fuquan Palace area and sanitarium area, the deep heat can quickly reach the shallow strata and give rise to local abnormal high temperature in the shallow part. The geothermal fluid belongs to continental sedimentary water that is formed in the strata with dissolved salt brine, and is mainly derived from meteoric water.

Abstract:Abstract: Northeastern Yunnan has rich resources and hence serves as a major coal resource base area in southwestern China. Based on previous researches in the study area, the authors made a comprehensive analysis of field geology, mountain projects and drilling data and, on such a basis, investigated the variation regularity of mineable coal seams in major Upper Permian coal-bearing strata. The results show that, spatially from east to west and temporally from early Xuanwei to late Xuanwei, the mineable coal seams are uplifted and tend to ‘migrate’ from the bottom upward. An analysis of the factors responsible for such variation regularity and the variation of the ancient geography from west to east shows that the gradually stabilized structural conditions and periodic eustatic sea level jointly control the distribution and ‘migration’ of the mineable coal seams. In addition, the mineable coal-seams and mineable segments in different places are pointed out, which is of practical guiding significance for the exploitation of the coal resources in the study area.

Abstract:Abstract: The Salawusu River Valley, located in the transition zone between the loess plateau and the Mu Us desert, has kept sensitive records of paleoclimate since the last interglacial period. The profile which contains the aeolian sand with some interbeddings of sandy soil and limnetic paleosol facies in the downstream part of the valley was recently termed Jiufangtai Stratigraphic Section. In this paper, the authors focused the study on the top section since the interstadial epoch of the last glaciation and employed a series of geological methods, such as the AMS-14C, OSL dating method, grain size, magnetic susceptibility, Rb, Sr elements and their ratios. Based on the data obtained and the climatic-stratatigraphic comparison with the relative marine isotope stage, the authors further divided the strata into the following sequences: (1) the MIS 1 sequence (0~11 ka B.P.), which was a mainly dry period at the beginning of the Holocene, consistent with records from the arid-semiarid transition zones in other places. And the 1.5~1.8 cal ka B.P. was a wet phase when the modern Salawusu River formed; (2) MIS 2 sequence (11~28 ka B.P.), which was a lasting and stable dry and cold period; (3) MIS 3 sequence (28~52 ka B.P.), which mainly contained 2 warm and humid periods (MIS 3a and MIS 3c), and a cold period (MIS 3b), similar to things of MIS 1. The lacustrine facies in MIS3 sequence was similar to the particular warm and wet stage in the Tibetan Plateau and its adjacent areas, which recorded the strong summer monsoon event during 30~40 ka B.P.. It is concluded that the paleoclimatic records had a comparable sedimentary response to the global and regional climate events. Thus, the valley is an ideal zone for studying climate changes in China. In addition, some comprehensive analysis should be conducted in the reconstruction of the valley paleoenviroment history, because there are varying degrees of limitations in different assumptions.

Abstract:Abstract: In this study, the authors reconstructed the distribution of ice sheets on Gondwana Supercontinent in Paleozoic based on the methods of stratigraphic correlation and paleomagnetism. By studying the Paleozoic glacier deposits on the major plates of Gondwana, the authors have reached the conclusion that three major glacial events occurred on Gondwana Supercontinent in Paleozoic, which included (1) Late Ordovician-Early Silurian glacial event, (2) Late Devonian-Early Carboniferous glacial event, (3) the end of Late Carboniferous-Permian glacial event. The Late Ordovician-Early Silurian glacier event lasted a shorter period of time, and the glacier deposits were limitedly distributed on West Gondwana. Compared with the first glacier period, the ice sheets during the Late Devonian-Early Carboniferous glacier period were even smaller and mainly distributed in South America Plate, whereas the last glacial event lasted for the longest time and influenced the largest area, and the ice sheets were distributed on all the major plates which constituted Gondwana Supercontinent. Furthermore, the centers of ice sheets in the three glacial events were all close to the South Pole, but they were not completely coincident. It is thus held that the major factor affecting the distribution of ice sheets on Gondwana Supercontinent was the temperature. In addition, basin dynamics, topography, attributes of glacier and other specific factors could also affect the distribution of ice sheets. Combining the authors’ field work in Baoshan Block with achievements of other researchers, the authors have reached the conclusion that only the Late Carboniferous-Permian glacial event had an effect on China’s blocks, and mainly affected the blocks in Southwest China, including Baoshan Block, Tengchong Block, Lhasa Block and Qiangtang Block.

Abstract:Abstract: With central south Hebei plain as the study area, to study iodine geochemistry of soil in detail and explored its controlling factors, the authors studied the distribution of iodine based on the analysis of iodine content in different soile stypes and different sedimentary environment.The results show that the most content of iodine element in different soile stypes of central south Hebei plain is coastal solonchak and bog soil.The sedimentary environment with more iodine element content in the deep soil is the lakes and swamps phase of Baiyangdian and coastal plain of Cangzhou,the sedimentary environment with lower iodine element content is alluvial fan plain of Hutuo River in the middle of Taihang Mountain and Zang River. The distribution of iodine element in soil is significantly affected by physical factors and human factors in the area,with the physical factors play the leading role, on this basis, human factors have a greater impact on the iodine element content of topsoil.