Abstract:Through systematic study of geochemistry, zircon U-Pb dating and Hf isotopic compositions on rivers’ overbank sediments in the Great Hingan Mountains, southeast segment of Palaeozoic Central Asian Orogen, it shows that REE and other trace elemental characteristics of the sediments are consistent with those of upper crust. There exist significant differences in contents of mineralized elements between northern and southern segments, which may indicate different mineralization for corresponding elements in different segments. The overbank sediment in the Xar Moron River indicates significant contribution of material from the northern margin of the North China Plate whatever is based on its content of SiO2 or Nd isotopic composition. The most northerly sediment of the Nanweng river also shows the contribution of material from the Precambrian micro-continental block attached to the Siberian Plate on the basis of Nd isotopic composition. Average Nd depleted mantle model age of bulk sediments is almost consistent with that of Hf depleted model ages of zircons, which are 1.03Ga, 1.01Ga，respectively. The oldest zircon U-Pb age is 2473Ma, corresponding Hf depleted model age of which is 3.75Ga. Therefore, the basements of micro-continental blocks of the Great Hingan Mountains were formed during Paleo-proterozoic by intra-continental magmatism of precursor block (3.75Ga). The micro-continental blocks began to separate from the parent block during Mid-proterozoic, which may be a prelude of the Paleo-Asian ocean’s opening. The most intensive crustal accretion from the depleted mantle to the regional crust took place during the period of Neo-proterozoic-Mid-proterozoic to Late Early Paleozoic, which consists of oceanic crusts of Paleo-Asian Ocean and underplating mafic-ultramafic rocks beneath the micro-continental blocks. The Paleo-Asian Oceanic crusts subducted to the Siberian Plate in north and to the North China Plate in south primarily during Late Paleozoic. The ocean disappeared during Late Permian, when intra-continental mountain-building started. The underplating mafic-ultramafic rocks beneath the micro-blocks were partially molten affected by Paleo-Pacific tectonic regime during Mesozoic. Simultaneously，part of basements involved in the magmatism. Mesozoic volcanic and intrusive rocks consist of 80% present occurring crust. But there is no direct contribution of material from depleted mantle during the magmatism.

Abstract:Geochronology and geochemistry of dioritic gneiss in the Lianggehu region, Qiangtang Basin is examined for the first time so as to determined its age and genesis. Results show that dioritic gneiss is composed of a suite of diorite and gabbro-diorite. Zircon occur as long columnar euhedral and hypidiomorphic crystals with well-developed tight oscillating zonal structure, indicating magmatic origin. LA-ICP-MS U-Pb zircon dating of three pieces of dioritic gneiss samples are (220.48±0.49)Ma、(217.9±0.51)Ma and (219.98±0.49)Ma respectively, with an average value of (219.45±0.50)Ma, indicating that dioritic gneiss was formed at the age of Triassic Carnian. The SiO2, MgO and Al2O3 contents of dioritic gneiss range from 55.17 to 58.61%,1.71 to 2.74% and 20.18 to 21.43% respectively. The dioritic gneiss are characterized by high Mg# value (0.38~0.53) , Na enrichment (Na2O/K2O= 1.17~7.38), strong LREE and LILE enrichment , obvious negative anomalies of HFSE, and no Eu anomaly. The isotopic (87Sr/86Sr)t and εNd(t) values of dioritic gneiss vary in range of 0.70868 to 0.71024 and -3.4 to -2.8 respectively. These characteristics combined with lead isotopic parameter indicate that the magmatic source of dioritic gneiss is derived from lithosphere mantle modified strongly by the continental crust.

Abstract:In this paper, we focused on the structural and geochronological analyses for the Yingba area in western Inner Mongolia, China. At least three stages of Late Proterozoic to Mesozoic tectonomagmatism have been identified. New and previous zircon U-Pb ages have revealed Carboniferous (325~313 Ma) granodiorite and porphyritic granite, Early Permian (291~277 Ma) alkaline granite and purple red medium-fine grained granite and Early Cretaceous (~134~130 Ma) pegmatite and quartz monzonite. The first tectonic event is characterized by NW-SE compression after the Early Permian (290.9±1.8 Ma), which generated the low-angle NW-dipping gneissic foliations in the granodiorite and alkaline granite. The second event is indicative of NW-SE extension, during which a SE dipping low-angle ductile shear zone, which is characterized by the medium-high temperature (450~650 ºC) mylonite, crosscut the gneissic granodiorite and gneissic alkaline granite, and so it apparently postdated the first tectonic event (<290.9±1.8 Ma). The ductile shear zone is crosscut by the ~134 Ma pegmatite veins, indicating that the extension occurred before the Early Cretaceous pegmatite veins. The third tectonic event is represented by NW-dipping moderate-angle brittle normal faults, which resulted from NW-SE extension after the Early Cretaceous and crushed the ~134 Ma pegmatite into cataclasite. The Yingba area has recorded a typical process from the formation of an orogen to intracontinental extension during Late Proterozoic to Mesozoic.

Abstract:Granite samples from Risong granite of Ritu county-Lameila pass area, Western Tibet, were selected for a detailed geochronological and Hf isotopes study. Petrochemical data showed that Risong granite belongs to calc-alkalic rock series and the vast majority of all samples contain Di in CIPW composition. All samples show in rightly-deviation from the LREE to the HREE with the obviously negative Eu anomaly (δEu=0.42-0.85), and enriched in Rb, Pb, Th and depleted in K, Ba, especially in HFSE (Nb, Ta, Ti). Different from previous studies define its age to late-Cretaceous to Eocene, this article divided the Risong granite into two intrusive of early-Cretaceous and late-Cretaceous. LA-ICPMS U-Pb zircon ages for monzogranite(D1045-2) were 108.4±2.1Ma(MSWD=2.4, n=18), indicating that it were generated in early Cretaceous. Sample of monzogranite (D1045-2) showed positive Hf isotopic initial ratio and variation between 1.49 to 3.86(with 2.50 averages); Sample of quartz diorite (D1045) showed negative Hf isotopic initial ratio and variation between -2.09 to 0.15 (with -0.49 averages). Two samples showed 762.95Ma-884.47Ma (D1045-2), 959.1Ma-1073.49Ma (D1045) of two stage model ages respectively. Zircon Hf isotopic compositions of two samples all showed narrow ranges in Hf isotopic initial ratio and two stage model ages, indicating that the material source magma of granites had homogeneous in Hf isotopic compositions. The characteristics of the zircon U-Pb ages and Hf isotope features, were in accordance with the features of early Cretaceous magmatisms of North Gangdese.The granite were formed by granitic magmatisms during the oceanic crust orogenic subduction, as the magmatic response to the Bangong-Nujiang Tethys evolution.

Abstract:Jingde pluton is a typical high Sr/Y granodiorite emplaced in the eastern Jiangnan Orogen, China. New LA-ICPM zircon U-Pb dating for one diorite yields an emplacement age of 141±1Ma. The pluton is composed of monozograntie and granodiorite. The biotite in the pluton falls into Mg-type. plagioclase is mainly oligoclase and andesine. The pluton possesses high SiO2 ( 66.01% ~ 70.87%), Al2O3（14.91% ~16.24%），total alkalinity（K2O+Na2O＝6.64% ~ 8.01% ），K2O/Na2O（0.78~1.04），Sr（189 ×10-6 ~ 452×10-6）and LREE，low HREE and HFSE contents， and slightly negligible to positive Eu anomalies (δEu＝0.81~1.18). Consequencely, the samples have high Sr/Y（23 ~ 66）and (La/Yb)N（13 ~ 58）ratios. On the other hand, they have low MgO (or Mg#), Cr and Ni contents. The pluton has relatively higher Nd isotopes (εNd(t)＝‒12.92~‒6.28) and younger tDM2 model ages（1.4~1.9Ga）, with mafic microgranular enclaves (MMEs) suggesting the importance of mantle material in the magma source. The mafic magmas ascended from the metasomatized and heated the lower crust, triggering partial melting to form the Jingde pluton, with input of mantle-derived materials.

Abstract:Paleogene adamellite and feldspar granite developed in Tengchong-Lianghe area, Western Yunnan, recorded magmatism information in the collision between Indian and Asian continents. The LA-ICP-MS zircon U-Pb age of typical adamellite is 51.4±0.4Ma, and Hf modal ages are 1.46-1.55Ga, εHf(t) values are -6.65 to -5.30. Major elements of Paleogene granite from Tengchong-Lianghe area, are characterized by high SiO2 (68.96%-78.68%), K2O (4.56%-6.29%) and Al2O3(12.40%-16.42%), and have K2O/Na2O ratios of 0.93-7.24, A/CNK values of 0.99 to 2.31 with Al2O3>(K2O+Na2O)，belong to metaluminous-strongly peraluminous high K calc-alkaline granite; Their trace elements show strong negative Eu anomalies with Eu/Eu*values of 0.19 to 0.51, enrichment of Cs, Rb, Pb but depletion of Sr、P、Ti、Ba、Nb、Ta. Elements geochemical features signified that these granites might be generatedfrom upper crust by partial melting of metagraywacke. Based on the regional geology, we suggested Tengliang granites (62-51Ma) magmatic response events on the peak period of India-Asia collision.

Abstract:Hutouya pluton is a middle-late Triassic (Late Indosinian) granitic body in Qimantage minerogenetic belts, which mainly composed by biotite-monzonitic granite, syenogranite and little granite with diorite inclusion. The rocks have high silicon (70.71%～77.67%), high potassium (4.7% in average) and are rich in alkali (Na2O K2O=7.86%～9.1%), and the average value of K2O/Na2O is1.36, the value of A/CNK spread within the limits of 0.91～1.05. The rocks belong to high-K,cala-alkaline series peraluminous granitoids. The rocks have middle ∑REE values with an average of 120.10 μg/g, values of δEu within the limits of 0.04～0.47, values of (La/Yb)N spread among1.52～8.06, the rare earth patterns of rocks/chondrite shows the right deviation of ‘V’ type with the character of negative Eu and flat HREE. The rocks are rich in LIL and HFS, and evident negative anomalies of Ba, Sr, Nb, Ti, P. According to the character of regional geology, the diagram of A/FM-C/FM and the spider pattern of trace elements, the author infers that the Hutouya granite is the production of partly fusion of original resource and participation of crust. Based on tectonic history and the diagram of structure environment, the Indosinian granitoids(including Hutouya pluton) formed in post-collisional tectonic setting of syn-orogenic stage. The formation mechanism of Indosinian granitoids is as follows: between later Permian and earlier Triassic, Animaqing ocean basin downthrust to the south margin of Kunlun micro block and form the tectonic setting of syn-collision or within plate, the original basic rock closed association with mantle-derived magmata also developed in this period; during the middle-late Triassic, the pressure stress become weaker after the main collision, and the depth pressure got lower, that made the crust thicker and hotter, and melting point of rocks lower, finally the basic magmatite house was partly melting, and the melt emplace into the upper crust in the open tectonic setting.

Abstract:Tadong iron deposit is the largest submarine volcano plume - metamorphic - reformation iron deposit in Jilin-Heilongjiang metallogenic province. The geological characteristics, geochemical characteristics, electron-probe analysis and Re-Os dating of pyrite in the deposit were reported for the first time in this paper. The deposit occurs in ore-bearing rocks of Tadong Group. The ore bodies show structures banded, lamellar banded or lenticular-like structures. The attitude of the ore body is consistent with surrounding rocks. The banded structure is a main ore structure, secondary layer laminae, compact block, and crumpled structure and so on. Geochemical data display that Tadong iron deposit was formed in the alternative depositional environment of submarine chemical deposition - submarine basic volcano eruption - submarine volcano clastic deposition. The deposit has characteristics of SEDEX type deposits. Its tectonic environment is arc tectonic environment of continent to continent collision zone. The major element content of magnetite in Tadong iron ore FeOT values are 88.49%~93.72%, average 92.35%, SiO2 values are 0 ~ 1.058%%, average 0.075%. TiO2 values are 0 ~0.13%, average 0.03%. Al2O3 values are 0~ 0.30%, average 0.06%, MnO values are 0~ 0.08%, average 0.03%. TiO2 values are 0 ~0.13%, average 0.03%. Genetic types of inmagnetite in Tadong iron ore include magmatic rock type, volcanic rock type, and sedimentary-metamorphic type. The major element content of pyrite in Tadong iron ore Fe values are 43.534%~48.246%, average 46.779%, S values are 48.728%~54.402%, average 51.837%. S/Fe values are 1.782~2.072, average 1.931. The values belong to the sulfur week depletion type. The trace element content of pyrite in Tadong iron ore Co values are 0.039%~0.573%, average 0.143%, Ni values are 0.008% ~ 0.502%, average 0.077%. Co/Ni values are 0.165~19.759, average 4.04. The deposit has the characteristics of volcano hydrothermal and metamorphic hydrothermal iron deposit. Five samples of pyrite for Re-Os isotopic dating are analyzed and W ( Re ) range from 1 172× 10-12 to 29810× 10-12 , w ( Os ) range from 20× 10-12 to 184×10-12. 187Os/188 Os range from 3.82 to 52.11, 187Re/188Os range from 601 to 7 739. The model ages value from 370Ma to 448Ma, Corresponding isochron is 401± 41Ma, MSWD=10.2, Initial187Os/188Os is 0.3± 3.4. Higher 187Os/ 188Os and γOs(t) value suggests that the ore-forming materials originated from the crust .The age is indicated that the Tadong iron deposit was formed in the late Caledonian. Ore-bearing rock series were formed in the early Palaeozoic, but not were formed in late Proterozoic.

Abstract:The Da Hinggan Mountain metallogenic belt is one of most important nonferrous metal metallogenic belt in China, the resources potential is huge. The northern Da Hinggan Mountain area is the geological work blank area except for Xinjiang, the mineral exploration and research level is very low. This paper summarizes the regional geochemical field characteristics, the large and medium-sized endogenous metal deposit distribution and regional geological condition in north Da Hinggan mountain area. The preliminary research indicate that advantages endogenous metal mineral is Molybdenum, Ag-Pb-Zn deposits, followed by gold and copper deposits, the potential for minerals uranium. In two sides of Derbugan fault, Elunchun-Yiershi deep fault, there are bigger various in geochemical backgrounds, metallogenic environment, minerals and mineralization types. The north Da Hinggan metallogenic belt is divided into: Derbugan, the Da Hinggan mountain West slope, Lengjiang, three third order metallogenic belts and ten fourth order metallogenic area.

Abstract:Shanyang-zhashui ore concentration area located the Late Paleozoic fore-arc basin of Mid-Qinling Orogenic Belt. There are Devonian and carboniferous strata in the ore concentration area, and a large number of Indosinian and Yanshanian magmatic intrusions exposed in the area. Extensive alteration and CuMo mineralization are occurred on the Yanshanian rocks and the contact between the rocks and strata. Through the research of minerals of the rocks, feldspars in the rocks are potash feldspar and plagioclase, and a part of the feldspars had occurred alteration; biotites are protogenetic magnesia biotite; hornblendes are belong to endenite and magnesia hornblende; chlorites are delessite. Meanwhile, sphene and apatite appear in the Yanshanian rocks. Based on the composition of biotite and hornblende, we deem the rocks exposed in Shangyang-zhashui ore concentration area are I type granite and with the crust-mantle mixed solvent characteristics, which were formed in the orogenic belt environment. The rocks have similar crystallization temperature, which are during 701 °C to 789 °C. Magma of the rocks is with higher oxgen fugacity. On the basis of chlorite, altered temperature of the rocks are estimated, 250~355 °C, in which the Chigou rock had the highest temperature. The altered temperature illustrated the hydrothermal fluids forming the alteration in the rocks are medium-high or medium temperature fluid. Compared the rocks in Shangyang-zhashui ore concentration area with the metallogenic rock bodies of typical large or super-large porphyry deposit and porphyry-skarn CuMoAu deposit, we can find the rocks researched have a lot of similar features with the typical deposit, in forming environment, magmatic source and oxgen fugacity. The contents of TiO2, Al2O3, CaO and the ratioes of K/Na, Mg/Fe, Mg/ (Mg+Fe3++ Fe2++ Mn) and (Fe3++ Fe2+)/ (Mg+Fe3++ Fe2+) are consistent with the typical deposit; the compositions of apatite in the rocks have some similar characteristics with the metallogenic rocks of typical deposit. However, the compositions of Ti, Si and AlIV+AlVI, Fe3++ Fe2+ of biotites in the rocks are different with the metallogenic rocks of typical deposit. And the volatile matters of apatite, as F, Cl and S, are lesser than the typical, especially the content of SO3, which is adverse to ore-forming elements deposit, as Cu or Mo. The rocks were forming a deeper depth, which is a disadvantage for forming large scale mineralization. As a whole, the Yanshanian rocks in Shangyang-zhashui ore concentration have some advantage for forming porphyry or porphyry-skarn deposit, but there are some adverse conditions. Although the rocks are difficult to forming large porphyry or porphyry-skarn deposit, they have the potential to forming small and medium size deposit, so we also need to attach importance to the rocks in ore prospecting work in the future.

Abstract:This paper discusses biomarker geochemistry in low grade metamorphic source rocks of the Mohe Formation, Mohe Basin. The mainly object is to describe redox conditions and salinity of depositional environment and source of organic matter and thermal evolution of the source rock. The results showed that: (1) The carbon number distribution is C11~C27 and main peak is C17 of saturated hydrocarbon. ∑C21-/∑C22+ is between 4.0 and 6.3, with the average being 5.3. OEP is between 1.23 and 1.37, with the average being 1.31. Pr/Ph varies from 0.9 to 1.4, with the average of 1.2. The variation of gammacerane index from 0.23 to 0.30 and an average of 0.27; C35/(C31~C35) homohopane between 0.04 and 0.06. (2) The relative content of hopanoid is the highest, followed by tricyclic terpane, the relative content of tetracyclic terpane is the lowest. The relative abundance of the regular steranes C29 has the highest values, C27 by the second and then C28. Regular steranes show a pronounced “V” type of C27-, C28- and C29- components. (3) The contents of diahopanes and rearranged sterane are relatively low. The contents of β-carotane, oleanane and 25-norhopane have obvious mean peaks characters. Based on the analysis of multiple biomarker geochemistry and the depositional environments and tectonic evolution feature, we have drawn conclusions that: the source rocks in the Mohe Formation were deposited in relative high salinity and strong reducing environment of the lacustrine face, organic matters are characterized by mixed origins from higher plants and aquatic organisms, and they are mainly during the high-mature stage.