Abstract:Based on the 973 program and the northern sandstone type uranium survey program, this study tried to explain the"red and black"sandstone constraint on uranium mineralization. On the basis of summarizing temporal and spatial relationship between red layers and black layers of global sandstone uranium deposits and the sieving of more than 100,000 meters core drilling data of the northern continental basin, the authors selected Junggar, Ordos and Songliao basin as typical research objects. Through compilation of drilling chart of the basin, investigating well-connecting section of typical mining area and geochemical testing of key strata, the authors made a vertical and horizontal comprehensive analysis and comparison of"red and black"sandstone and uranium-bearing strata, and the results show that the formation ages of uranium-bearing strata gradually change from Middle Jurassic to Upper Cretaceous from west to east in China. There were at least 6 large-scale oxygen-rich red sedimentary events in Late Mesozoic period, which are respectively I. Middle Jurassic-late Jurassic early stage (Bathonian-Oxfordian), Ⅱ. Early-middle stage of the Early Cretaceous (Berriasian-Barremian), Ⅲ. Middle stage of Early Cretaceous (Barremian), IV. Late stage of middle Cretaceous (Cenomanian), V. Middle stage of late Cretaceous (Coniacian), and VI. Late stage of late Cretaceous (Campanian). The red layer and the black layer below constituting"red-black color structure" in I, V and VI stage are 3 important uraniumbearing strata in China. Geochemical and fossil data of the red and black layers in the typical basins show that the content of B, Sr and Cu and the ratios of Fe²⁺/Fe³⁺, B/Ga, Sr/Cu and FeO/MnO are obviously different between them. The content of Fe₂O₃ in the red layer is obviously higher, and the ratio of U and U/Th in the transition zone is obviously higher than other sides. Combined with development of strawberry pyrite in black layer and carbonate rocks in red layer, the authors hold that the red layer is a relatively strong oxidizing environment and the black layer is a relatively reducing environment, which respectively provide oxidationreduction conditions for the mineralization of sandstone uranium ore. The spectrum of uranium deposits is related genetically with red and black layer, industrial orebodies occur in tabular form in gray and grayish green sandstone. The red and black layer with the thickness of more than 500m is unfavorable for mineralization. The black and red layer formed in late Mesozoic continental basin has vertical zoning to represent the depositional environment change from oxidizing to reducing environment which provides "obstacle" and "field" for mineralization respectively. In conclusion, the authors put forward the "double color structure" metallogenic prospecting model for sandstone uranium deposit, in which the upper layer serves as the red oxide barrier, whereas the lower layer serves as black reducing barrier, and the sandstone uranium deposit (ore spot) transition zone is characterized by grayish green, gray sand enrichment and mineralization. The understanding obtained by the authors is significant not only for improving the metallogenic environment knowledge, metallogenic regularity and metallogenic model of sandstone uranium deposit but also for guiding the investigation of sandstone uranium deposits.

Abstract:The chromitite bottleneck has been going on for many years in China. In October 2015, Bureau of Land and Resources of Tibet announced the discovery of a 200 million tons of massive chromite deposit in deep exploration at Luobusa in Tibet, which achieved a major breakthrough in China's chromite prospecting, and the direction of finding more chromite deposits in the future was also pointed out. The podform chromite produced in the ophiolitic mantle peridotite is the main source of chromium. The study of podiform chromite mineralization and mantle peridotite is necessary for further finding the chromite deposit and relieve the bottleneck of the chromitite resources in China. Podiform chromite produced in the ophiolite is the main source of chromium and an important strategic resource for China. Research on the genesis of the podiform chromitite and mantle peridotite is necessary for further finding the chromite deposit and relieve the bottleneck of the chromitite resources in China. With the discovery of deep minerals such as diamonds in podiform chromite and mantle peridotites in recent years, researchers have also begun to question the theory of formation of podiform chromite. With the first discovery of 200 million tons of massive chromite orebody, the new understanding that podiform chromite is formed in the depth was raised, and its formation process mainly has gone through four stages. The crust and oceanic crust material of the early subduction to the mantle transition zone (410-660 km) is dehydrated and dismembered, and the heat and fluid produced by the transition zone contribute to the melting of the mantle and the release and aggregation of chromium. The chromitite ore slurry is driven by the mantle plume and is transported to the top of the transition zone for condensation and consolidation. The authors have reached the conclusion that the formation of ophiolites is a mutli -stage process involving subduction of lithospheric slabs into the transition zone, crystallization of chromian spinel and some massive chromitites at depth, incorporation of UHP and highly reduced phases into the chromitites, and entrapment of oceanic lithospheric slabs above subduction zones where they undergo varying degrees of interaction or reaction with MORB melts and SSZ melts. Several large massifs in the western part of the Yarlung Zangbo suture are similar to Luobusa in many aspects. They have experienced the same tectonic setting and the mineralization of podiform chromite, and there is a large prospecting space.

Abstract:Since the State Council promulgated the document concerning strengthening the geological work, the research and prospecting for coal resources in China have obtained ten major achievements, which have largely ensured the national needs for energy resources. However, the proportion of the scientific and green development of coal is still very low and, in the western part of China, where the relatively favorable coal development conditions and coal production are dominated, the damage of water resources and the harm to surface ecology have already restricted the green development of coal resources. Coal utilization is facing serious pressures from air pollution control, greenhouse gas emission reduction, and ecological and environmental protection. The coal geology still has eight difficult problems which need to be studied in the future.

Abstract:With the rapid development of new energy vehicles, lithium as an energy metal is increasingly important in recent years. This paper briefly summarizes the progress of the lithium prospecting both in China and abroad between 2015 and 2016 and the development trend. The authors focus on the progress and prospecting of brine type, hard rock type and other types of lithium ore as well as the hot lithium prospecting areas in the world. Meanwhile, combined with the development of new industry and lithium resources utilization, some suggestions are made on prospecting and exploration of lithium resources in China. People should further understand lithium resources in China and strengthen the prospecting work in key areas so as to provide resources for the construction of large-scale lithium resources base. Geologists should not only focus on the brine type and hard rock type lithium mines but also pay attention to the prospecting for new types of lithium ore so as to improve resource utilization efficiency and promote the transformation and upgrading of related industries. Scientists should begin to study the recycling of lithium and the highend exploitation and utilization of lithium as an energy metal for occupying the technical key point to provide a scientific basis.

Abstract:Interaction between oil-gas and sandstone type uranium has aroused much interest among geologists, especially uranium geologists. In spite of rapid development of mineralization theory for single energy mines, the study of interaction is very insufficient. Therefore, this problem should be regarded as the key frontier scientific issue which deserves investigation. Based on an analysis of distribution characteristics of uranium and oil-gas, microscope testing, geochemical calculation, it can be inferred that uranium enrichment can be improved by adsorption, reduction, uranium-supply and preservation of oil-gas, in which asphalt and organic acid, cracked by oil-gas, can adsorb uranium strongly. For reduction of oil-gas, high valence and activated uranium ion can be reduced to +4 valence and form stable uranium minerals by more reducing gas, such as H₂, CH₄, CO, and H₂S. By means of acid dissolving, extraction and metallic-organic complexation, organic acid, produced by the interaction of oil-gas and SO₄^2-, can accumulate partial uranium nearby surrounding rocks. And then this uranium can be released in mineralization location, which can reform mineralization and increase the source of uranium. Besides, more reducing H₂, CO, escaping from oil-gas, can cause acidification and kaolinization of the formation, which leads to the feature that the oxidation zone is slightly alkaline and the metallogenic belt is slightly acidic. Therefore, the interaction between oil-gas and uranium can be very important for the determination of uranium-bearing beds, locating of uranium deposits, developing of mineralization theory, and oil-gas exploration guided by‘chimney effect’.

Abstract:In western Henan Province, the rare earth ore deposit in Taiping Town is a newly-found medium-sized light rare earth deposit. Four orebodies were delineated in the three rare earth veins. The average thickness of the orebodies is 1.77 m, the average grade is 2.23 percent, the preliminary estimation of the amount of the resources is up to 100000 tons. Rare earth orebodies occur in the Mesoproterozoic plagiogranite and Erlangping Group, north of Taiping Town-Banshanping anticline, and are strictly controlled by NW-trending structures. The ∑ LREO accounts for 83.23%-99.35%, The ∑ HREO accounts for 16.77%-0.65%, and the distribution ratio of CeO₂+La₂O₃+Nd₂O₃ is 79.56%-94.15%. Rare earth mineral mainly is bastnaesite.The major rare earth minerals belong to the strongly selective partition pattern which is rich in LREE with feature of Ce > La > Nd. The rare earth ore reveals a depletion of light rare earth and enrichment of heavy one, with a weak positive Eu and indistinct Ce anomaly as well as distinct fractionation processes. The average ratio of Eu/Sm is 0.38; the ratio of Th/U is high, the indictation of magmatic origin is similar to bariterare earth distribution pattern. The veined light rare earth ores fill in the fault structures which formed in Yanshanian and were superimposed upon the Erlangping Group and Zhangjiazhuang rock mass. So the ore-forming epoch is not earlier than(108±1)Ma. The origin of the deposit belongs to the quartz vein and altered rock type, controlled by the crust-mantle mixed source and faulted structure. Exploration indicators include the filling materials composed of quartz vein and fluoritization baratization pyritization, altered rock, weak Th radioactive anomalies and low content of U. The results obtained by the authors are very important for theoretical research on rare earth minerals as well as prospecting and work deployment in Henan Province.

Abstract:Jiamusi massif is located in the northeast Asia early Precambrian landmass, where metamorphic rocks well developed and constituted an important crystalline graphite enrichment zone. The SHRIMP U-Pb dating results of ore rocks from typical Luobei Yunshan and Jixi Liumao graphite deposits in Jiamusi massif show that ²⁰⁷Pb/²⁰⁶Pb age is (1855±5)-(1979±13)Ma and (476±9)-(575±12) Ma respectively for metamorphic recrystallization zircon and authigenic zircon. The geochemical characteristic analysis indicates that the ore rock is enriched in large ion lithophile elements such as Rb, Ba and high field strength elements such as Zr, Hf, Th, U, Nb and Ta, and Rb/Sr ratio of ore rock is higher than continental crust Value 0.24, suggesting weak cyclic sedimentation; Sr/Ba ratio is lower, implying that magma was derived from the continental crust remelting; terrigenous material is dominant; the average V/Cr ratio is 4.58, average V/(Ni+V)ratio is 0.90, suggesting a weak reduction environment; the light rare earth element values are higher than those of heavy rare earth elements in the two typical deposits; negative europium anomalies are obvious for Luobei Yunshan mineral deposit, implying shelf shallow sea sedimentary characteristics; cerium is abnormal in Jixi Liumao deposit, indicating that the source material was dominated by shallow sea sedimentary materials. Mixed granite dike of rare earth elements in the study area exhibits a positive europium anomaly distribution curve, suggesting the characteristics of foreign magmatic hydrothermal metasomatic rock. Ore rocks of typical graphite deposit in Jiamusi massif were subjected to regional metamorphism of high temperature and high pressure in Paleoproterozoic period, and later experienced the pan-Asian structural activity under the background of tectonic magmatic intrusion in early Paleozoic period, which caused further proliferation and formation of giant crystal flaky graphite.

Abstract:The Huize super-large sized Ge-Ag-rich Zn-Pb deposit is a typical deposit in the Sichuan-Yunnan-Guizhou lead-zinc polymetallic ore-forming area. On the basis of enormous field survey and tunnel measurements and through studies of petrology and geochemistry of ore-bearing dolomite, the authors investigated zonation regularity of mineralization and alteration and structural ore-controlling role, and the results show that ore-bearing dolomite was formed by dolomitization in the ore-forming process, characterized genetically by typical hydrothermal alteration. Its genetic type differs from that of fine-grained dolomite and dolomitic limestone in the Baizuo Formation. According to the mineral compositions of ores and altered wall rocks, the degree of mineralization and alteration and the distribution characteristics, the zoning regularity of mineralization and alteration has been revealed:from the orebody to the wall rock, there exists the zoning of Zn-Pb ores and Zn-Pb mineralized pyrite zone→Zn-Pb and pyrite-mineralized coarse-grained dolomite zone→gray coarse-grained dolomite zone, beige coarse-grained dolomite zone, flesh red coarse-grained dolomite zone, net veined dolomitized limestone zone, and weakly dolomitized limestone zone. Mineralization and alteration zoning is obviously controlled by interlayer faults on the upper wall of the thrust-fold structures (Kuangshanchang, Qilingchang, Yinchangpo oblique faults and its derivatives folds). On such a basis, the mineralization structure of ore -forming structure, altered dolomite and Zn-Pb orebody has been established. The results obtained by the authors not only enrich the metallogenic theory of the HZT-type Zn-Pb deposits but also have important practical significance for comprehensive geological study of the resources crisis mines in the northeastern Yunnan ore concentration area and the Sichuan -Yunnan -Guizhou metallogenic area.

Abstract:Algoma-type Banded Iron Formations (BIFs) are marine chemical sedimentary rocks that are generally interlayered with volcanic rocks and/or sedimentary sequences in Archean greenstone belts, mostly followed by metamorphism and deformation. Because rare earth elements (REEs) are usually not fractionated during diagenesis and metamorphism, REE patterns are thus regarded as a powerful tool to understand conditions under which BIF were deposited. Located in the northern North China Craton (NCC), BIFs such as Sanheming, Gongyiming, Dongwufenzi and Gongjucheng are hosted by the Guyang greenstone belt, of Seertengshan Group which consists of multiple sequences of metavolcanic rocks and metasedimentary rocks. The regional metamorphic grade ranges from upper greenschist-to lower amphibolite-facies. The BIFs are composed of laminated magnetite and white to gray quartz associated with amphibole layers. Moreover, minor chlorite, garnet and plagioclase, rich in Al, are observed interbedded with quartz and magnetite. Based on the content of immobile elements, the samples can be subdivided into two types:pure and contaminated. Cr/Th ratios in the contaminated BIF indicate that detritus is mainly from basaltic rocks. Normalized by post -Archean Australian Shale (PAAS), REE patterns of pure and weakly contaminated BIF are characterized by depletion of LREE, positive La and Y anomalies, and relatively high Y/Ho ratios (>29), which are typical of modern seawater and some other Archean BIF. Slightly negative Ce_PAAS anomalies are present in most samples, suggesting its precipitation from anoxic waters. Large positive Eu_PAAS anomalies may indicate that, during deposition of BIF, the oceans were greatly influenced by high-temperature (>250℃) hydrothermal fluxes which accounted for 0-10%. However, REE patterns of highly contaminated BIF are obviously distinct. Disordered destitution of this kind of BIF indicates that deep water in limited regions or time was not quiet before the deposition of BIF.

Abstract:The newly-discovered Early Jurassic rhyolite in Badaguan area of Da Hinggan Mountains is of great significance in investigating the tectonic evolution history of Northeast China. The rocks are mainly composed of rhyolites, with a small amount of dacitic and rhyolitic tuffs. LA-ICPMS shows the rhyolites were formed in Early Jurassic, and their formation ages range from 185 Ma to 190 Ma. Geochemical studies show that the rhyolites are characterized by rich silicon and alkalis, poor calcium and magnesium and high FeO_T/MgO ratios. Hence the rhyolites belong to high-potassium calc-alkaline rocks. All samples have the similar characteristics of REE patterns, which are characterized by relatively poor total REE content (∑REE=103.80×10^-6-194.31×10^-6), significant fractionation of HREE and REE[(La/Yb)]_N=7.12-10.22) and moderate Eu negative anomalies (δEu=0.34-0.74). The rhyolites are characterized by enrichment of Rb, Th, U, K and LREE, strong depletion of Ba, Sr and HFSE (e.g., Nb, Ta, P and Ti), and relative loss of Nb, Ta. The relatively low Ga/Al ratios indicate that the rhyolites are I-type granites of high differentiation. The discrimination diagrams of (Y+Nb)-Rb and (Yb+Ta)-Rb show that the rhyolites were formed on the active continental margin. The comprehensive studies show that the Badaguan area was located on an active continental margin before Early Jurassic, which was affected by the subduction of Mongol-Okhotsk plate towards metamorphic rocks in the Erguna Block.

Abstract:The amphibolite, which is lenticular in shape and is wrapped in metamorphic peridotites, was discovered in the Kalamaili ophiolitic mélange belt, East Junggar, Xinjiang. LA-ICP-MS zircon U-Pb dating of the amphibolite yielded an age of (402.7±4.9) Ma, indicating that it was formed in Early Devonian. Petrographic, whole-rock chemical and Sr-Nd isotopic data suggest that the source rocks of the amphibolites were probably the meta-gabbro. The rock samples have SiO₂, MgO and Mg# values of 47.58%-50.57%, 8.04%-9.12% and 63.89-67.64, respectively. They also have Ni and Cr values of 68.9×10^-6-99.2×10^-6 and 306×10^-6-398×10^-6. All these geochemical data are similar to the average value of MORB. The REE of the rocks show weak depletion to flattening pattern. The features of the trace elements of the rocks are similar to those of the N-MORB, suggesting no obvious depletion of Nb, Ta, Zr, Hf and Ti. The samples have high ε_Nd (t) values varying from 8.7 to 9.2, suggesting that the original magma of the rocks was derived from the depleted mantle. On the TiO₂ versus FeO_T/MgO and Th versus Ta versus Hf/3 diagrams, all samples fall in the MORB field. Combined with the geological background, the authors hold that the amphibolite was probably formed in a midoceanic ridge setting and represented the lithosphere fragments of the dismembered ancient ocean basin, being a part of the Kalamaili ophiolitic mélange. This research reveals that the opening time of the Kalamaili ocean basin was the Early Devonian at least.

Abstract:The volcanic rocks of the Chaotugou Formation in Chifeng area of Inner Mongolia consist of meta-basalts and metarhyolites and exhibit typical "double peaks", with the SiO₂ content being 46.24%-56.6% and 77.59%-85.75% respectively. Zircon LA-ICP-MS U-Pb dating of rhyolite yielded U-Pb ages of(359±1) Ma-(360±1)Ma, which represent the time of crystallization of the volcanic rocks. The volcanic rocks were formed in late Devonian Famennian age. Geochemically, meta-basalts (or basaltic andesites) are characterized by enriched LREE, depleted HREE, slightly negative Eu, Nb, Ta, Sr and Ti anomalies and high abundances of LILE and HFSE, with the (La/Yb)_N ratios from 2.4 to 8.76, and the ⁸⁷Sr/⁸⁶Sr initial values from 0.705076 to 0.707770; in addition, they have relatively high positive ε_Nd(t)values (+0.51 to +4.90) and relatively young T_DM (964-1090 Ma) ages. The mafic rocks might have resulted from the mixture of depleted mantle with crustal source. Meta-rhyolites are generally characterized by rich silicon, alkali and poor magnesium. They are characterized by enriched LREE, depleted HREE, noticeable negative Eu (δEu 0.12-0.43), Nb, Ta, Sr, P and Ti anomalies, relatively high U, Th and rather low Ba, Sr, Ti and P; the (La/Yb)_N ratios are from 7.07 to 11.07, ⁸⁷Sr/⁸⁶Sr initial values are high (0.713757-0.739647), negative ε_Nd(t) values are low (-1.75 to +2.54), and T_DM ages are relatively young (846-1156 Ma); besides, most zircons have the positive ε_Hf(t) values (-2.3 to +6.9) and relatively young T_DM ages (707-1074 Ma). The felsic rocks show an A-type affinity and might have come from a juvenile crustal source. According to their geochemistry and previous regional geological studies, the late Devonian volcanic rocks are basalts and rhyolites, suggesting a typical bimodal volcanic rock association and implying an extensional setting.

Abstract:The Jiajika ore deposit has become one of the areas with the richest Li resources in China and even in the world; nevertheless, remote sensing research on Li resources remains very insufficient. In this paper, geological mapping and oreprospecting studies in Jiajika area were conducted using remote sensing technology. Spectral library of typical rocks and minerals collected in this area was built, and spectral characteristics of rocks and minerals including biotite schist, grenatite schist, grenatite cordierite schist, hornstone, granite, spodumene-bearing pegmatite, pegmatite without spodumene, quartz vein, feldspar, spodumene monocrystal, biotite, and aquamarine were analyzed. Then geological mapping and ore prospecting were studied based on image processing and interpretation of middle spatial resolution remote sensing data LandSat 8 and high spatial resolution remote sensing data Geoeye-1. The results indicate that remote sensing technology is instructive for geological mapping and ore prediction of Jiajiaka type lithium ores and is likely to be a good indicator before geological study.

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