Abstract:Northern Hebei Western Liaoning, developing in boundary between Jurassic and Cretaceous with various fossils and volcanic ash bedding, is the marvelous region for the study of lithological, biostratigraphic, isotopic dating and Magnetic chronostratigraphy. The boundary of Jurassic and Cretaceous strata are between the Dabeigou and Dadianzi formations in the Luanping Basin, Northern Hebei and the Tuchengzi and Yixian formations in Yixian Beipiao area in Western Liaoning. The Dadianzi Formation consists of spore & pollen assemblages, such as Cicatricosisporites Luanpingspora Jugella; Ostracoda: Yanshanina Cypridea Rhinocypris assemblages, Cypridea Yanshanina Timiriasevia assemblages, Cypridea sulcata sub assemblages and conchostraca: Eosestheria Abrestheria assemblages and so on. Those fossils can be correlated in home and aboard, especially, spore & pollen and ostracoda are the same fossils in the correlation strata in England, French, Germany, Russia and Canada, with age of Early Early Cretaceous (Berriasian). However, the spore & pollen and conchostracain developed mainly in the lower part of the Yixian Formation are same as those assemblages in the Dadianzi Formation. Then, the Dabeigou Formation with spore & pollen assemblages: Poceites Podocarpidites Schizaeoisporites assemblages, Ostracoda: Luanpingella Torinina Eoparacypris assemblages and conchostraca: Nestoria Keratestheria assemblages show the Late Late Jurassic period (Tithonian) in the correlation with home and aboard. However, the boundary of Jurassic and Cretaceous is just developed in between the Dabeigou and Dadianzi formations. In the International biostratigraphic correlation shows the boundary between Jurassic and Cretaceous, eg. the boundary of the Tithonian and Berriasian. According to the isotopic data in North Hebei Western Liaoning region, the boundary age of Jurassic and Cretaceous is at 1307 Ma.

Abstract:Four NNE-striking major normal faults were developed along the Jiangsu segment of the Tan-Lu Fault Zone during extensional activities of Cretaceous. They are abbreviated by F1, F2, F3 and F4 faults from east to west. The normal faults controlled development of the NNE-trending eastern graben、western graben and a horst between the two grabens. The F5 fault occurs in the eastern graben. Detailed field investigation shows that active faults widely appear in the Jiangsu segment of the Tan-Lu Fault Zone. The F2, F3 and F5 active faults mainly show thrusting while the northern segment of the F1 fault presents reverse dextral slip. Computation of fault-slip data suggests that activity of the active faults results from ENE-WSW compression which is consistent with present stress filed in this region. Comprehensive analyses demonstrate that the latest active time for the F1, F2, F3 and F5 faults is late Pleistocene, and that the northern part of the F4 fault shows activity since Quaternary whereas the southern part exhibits no Quaternary activity. Fault displacement data and Quaternary deposition suggest that the F2 and F5 faults show more strong activity. Comprehensive analyses suggest that the active faults in the Jiangsu segment are derived mostly from direct reactivity of previous normal fault, and present the characteristics of inhomogeneous and discontinuous activities. The F5 active fault with a longer extension in the Shandong segment extends into the Jiangsu segment, and shows the formation mechanism of previous normal fault reactivity.

Abstract:A particular type of soft-sediment deformation structure, similar to imbricate structure, is developed in the Jurassic strata at Honggouzi, western Qaidam Basin, China. We refer to this structure as a duplex-like deformation structure, because it is inferred to have been formed by the action of fast-moving, submarine gravity current sediments gliding across a pre-existing semiconsolidated sedimentary layer. Duplex-like structures are mainly being composed of a series of planar and horizontal laminations, which with the other regions all containing planar, horizontal laminations. However, a minority of the structures developed in the Jurassic strata of the Qaidam Basin have a “Z” shape, and at the bottom of the structure, there is a particular structure similar in shape to a swallow’s tail or soft-deformation nodule. The average dip direction of the duplex-like structure is 301.2° and the average dip angle is 54.7°. Duplex-like deformed laminations are composeizhi819d mainly of weakly metamorphosed, extremely poorly sorted, feldspathic lithic graywacke. Sericite can be observed along bedding planes. The duplex-like structure occurs within a sequence of river-channel fine conglomerate, interchannel carbonaceous mudstone (shale), shallow-water delta sand–shale, shallow-lake calcareous mudstone, olistostromes, and a turbidite. At the bottom of the sequence are found brownish-red shallow-lake calcareous mudstone and carbonaceous mudstone and at the top are found olistostromes whose genesis is related to the slip and drag of a slumped body of submarine sediment. In combination with other symbiotic and associated structures, it is considered that the duplex-like structure was formed by the slumping and subsequent movement and traction of delta-front semiconsolidated sediments over the bottom sediments of a shore or shallow-lake sedimentary environment, probably triggered by an earthquake. After correction, the average dip direction of the duplex-like structure is 358° and the average dip angle is 48°.The attitude of the duplex-like structure indicates that the direction of gliding was from north toward south, which is consistent with the current location of the Altun Mountains, indicating that the Altun Mountains existed in the Jurassic. The orogenesis of these mountains likely involved seismic activity, and an earthquake was the triggering factor in the formation of the duplex-like structure by causing the slumping/gliding of the olistostrome sediments.

Abstract:The Mesozoic shoshonotic series volcanic rocks in the Lower Yangtze River reaches restricted in the Ningwu, Luzong, Lishui and Huaining four basins. The series are characterized by high-K and alkali enrichment. In geochemistry, these rocks enriched in strong incompatible elements such as Rb, Th, U and K as well as light rare earth elements (LREE), depleted in high-field-strong-elements (HFSE) such as Nb and Ta. The Sr and Ba characteristics of the rocks vary with lithology, indicating that the fractional crystallization of plagioclase may play an important role during magma evolution in these basins. Some geochemistry characteristics(such as Ce/Yb) of the shoshonotic series volcanic rocks in the basins are similarly with that of intra-oceanic island arcs, possibly because the lithospheric thinning allowed the asthenospheric mantle upwelled to relatively shallow depth where a greater proportion of spinel-facies melting can contribute to magma generation. The Nd and Sr isotope compositions of the rocks are roughly similar with the enriched subcontinental lithospheric mantle of the Yangtze craton, imply that their parental magma were mainly come from partial melting of the enriched subcontinental lithospheric mantle. But the tectonic setting of the basins are also play an obvious role on the magma characteristics, indicating the existing of crustal contamination. The whole shoshonotic series volcanic rocks in the Lower Yangtze region formed in a very short period from 128 to 134 Ma, with a peak about 130 Ma. The genesis of the shoshonotic magma may be related with the lithospheric thinning of the eastern China in the late Mesozoic.

Abstract:There is a set of calcicalkalic volcanic rocks with basalt-andesite in the northeast part of Bogda orogenic belt. The measured zircon 206Pb/238U age, 314.7±1.5Ma, by LA-ICP-MS, shows that the volcanic rocks formatted in Late Devonian. Their SiO2 changes in a narrow limits and they are featured with higher Al(Al2O3=15.81%~17.74%) , lower TiO2(TiO2=0.99%~2.44%), and being rich in Na(Na2O=2.82%~3.82) and deficient in K(K2O=0.17%~1.62%). Their REE abundance is from 103.75×10-6 to 137.26×10-6, with a rightly-oblique patterns type characterized by LREE enrichment and HREE depletion and a negative anomaly of Eu. In primitive mantle-normalized multi-elements spider diagram, they are enriched selectively with large-ion-lithophile elements (LIEL) such as Ba and U, uniformly and observably depleted high-field-strength elements(HFSE) such as Nb,Ta, Ti and Y, being similar with the geochemical characteristics of arc volcanic rocks. But their Nb/U, Nb/Th, Th/U have an affinity for N-MORB. The samples’ Mg#=54.46~64.34, Ni=73.56×10-6, Cr=156.37×10-6 and the same variation trend in TFe2O3 and TiO2 with SiO2 indicate that the magma have a process of crystal fractionation including Ti-Fe oxide. The correlation of La/Nb-Sr, Nb/Ta-La/Yb and the ratio of (Th/Nb)N, (Nb/La)N indicate that the magma suffers from the mixing of the crust. The simulation curve and Zr-Zr/Y diagram imply that the basalt formatted in intraplate, and its magma source is situated in the spinel stability field. It is the products of asthenosphere mantle/mantle medge melting with decompression in backarc basin. The age and situation of the volcanic rocks and the background of regional geology, reveal that the volcanic rocks in the northeast part of Bogda orogenic belt is the reflection of Kangguertage ocean subducting northerly, and provide a new evidence for the viewpoint that the Bogda Carboniferous rift valley should evaluate from the backarc basin for Kangguertage ocean subducting to Turpan-Hami plate during Early Paleozoic to Late Carboniferous.

Abstract:Zhengguang Au deposit is located at the Duobaoshan ore-concentrated area, northern of Great Xing’an Range. In order to constrain petrogenesis of contemporaneous igneous rocks and corresponding metallogenic background, a systematic study on major and trace elemental, geochronology and Hf isotope geochemistry was performed for the dacite porphyry in the Zhengguang Au deposit. Zircon LA-ICP-MS U-Pb dating indicates that dacite porphyry formed in early Ordovician(478~481Ma). Geochemical data shows that the dacite porphyry belongs to metaluminous or peraluminous and high-K calc-alkaline series and is characterized by SiO2≥56%(on average, 63.91%), high alumina contents (Al2O3, on average, 14.85%), low magnesium contents (MgO, average 2.70%), low Y and Yb contents (Y =6.00×10-6 to 7.74×10-6, Yb = 0.70×10-6 to 0.92×10-6), high strontium contents (an average of 368×10-6), high Mg# values, significant fractionation between light REE and heavy REE( (La/Yb) N = 8.74~11.54) , and unobvious Eu anomalies. All of these geochemical features are similar to those of adakites generated by partial melting of a subducted oceanic crust. Furthermore, zircon εHf(t) range from 13.03-13.31 with Hf isotope Two-stage model ages(tDM2) from 605Ma to 624Ma. Both geochemical characteristics and Hf isotope compositions suggest that the dacite porphyry in Zhengguang Au deposit was formed by partial melting of a juvenile subducted oceanic crust. The results of this study also demonstrate that there is a subduction of an oceanic plate, which is located between the Xing’an block and Songnen block, beneath the Xing’an block during the early Ordovician.

Abstract:Maevatanana gold deposit is located in the central part of Madagascar. Because of thick sediments, very little paper is reported about the Maevatanana gold deposit in Madagascar. In the Maevatanana gold district, ZK3-5 drill hole shows gold mineralization underside the granite vein, and the timing of metallogenesis at 534±13 Ma, as determined by the 187Re–187Os isochron age on pyrite, this is virtually coeval with the emplacement of post-collisional granite between 537 and 522 Ma during the waning stages of the East African Orogen. Field observation and experiment data indicates that the Maevatanana gold deposit is closely associated with the post-collisional granites after the East African Orogen, which were derived from mantle. The mafic magmas underplate the lower crust, generating voluminous felsic magmas by partial melting of the lower crust. Meanwhile, felsic-mafic magma mixing during the tectono-thermal reactivation of the East African Orogen produced voluminous volatiles. The volatiles extracted gold in the felsic magmas. Therefore, magma mixing during the tectono-thermal reactivation of the East African Orogen, which was important for the formation of the Maevatanana gold deposit.

Abstract:The Bainaimiao copper deposit, Inner Mongolia, is located in early Paleozoic Bainaimiao island-arc belt of the Mandula-Huolinguole arc-basin system in Xing’ An-Mongolia Orogenic Belt. The deposit is comprised of the northern and the southern ore belts. The host rock of the southern ore belt is greenschist, whereas the orebodies in the northern belt mainly occurred in the granodiorite porphyry. There is still controversy over the forming ages of the deposit and Bainaimiao formation for quite a long time. In this paper, two of the SHRIMP U-Pb ages of zircons obtained from the chlororite-plagioschist-the third member of Bainaimiao Group and granodiorite porphyry, are 439.8±6.7Ma and 433.9±2.2Ma，451.8±3.0Ma respectively, and the Re-Os isotopic age of molybdenite is 433.9±3.1Ma. Combining with the isotopic ages obtained by predecessors, it is suggested that the ages of the rock-forming of Bainaimiao formation and granodiorite porphyry ,and the ages of the ore-forming of Bainaimiao copper deposit formed in late Ordovician to eraly Silurian. Both of them were formed in the Caledonian tectonic-magmatic activity. Key words: Chlororite-plagioschist; Granodiorite porphyry; Zircon SHRIMP U-Pb dating; Re-Os isotopic dating; Bainaimiao copper deposit

Abstract:Abstract The Wuchuan-Zhen′an-Daozhen Al metallogenic district, north Guizhou province, located in southern Chongqing-central Guizhou bauxite metallogenic belt, is one of the major bauxite belts in Guizhou province. The bauxite-bearing rock series is the Middle Permian Liangshan Formation and the ore genesis of the bauxite belongs to paleo-weathering crust sedimentary type. The results of the chemical compositions analysis show that the Al2O3 contents and Ai/Si ratios of the earthy, clastic bauxite is higher than those of the oolitic, dense massive bauxite. Based on the microscopic observation, powder diffraction and electron microprobe analysis, the major minerals of bauxite ores are the diaspore, boehmite, and clay minerals, of which the diaspore is aggregated distribution and shows a short column, subhedral-euhedral crystal form, the clay mineral is mainly kaolinite and shows present island and residual cyclic occurrences, the other clay minerals include illite, montmorillonite and chlorite. Other minerals consist of pyrite minerals, magnetite, feldspar, quartz, rutile, zircon, anatase, calcite and dolomite. The main minerals in bauxite rocks are clay minerals, which are mainly kaolinite, and other minerals are similar with the bauxite. The content of Al2O3, SiO2, TiFe2O3 and TiO2 in bauxite ores is greater than 83% and the content of the loss on ignition is less than 14%, while the content of Al2O3, SiO2, TiFe2O3 and TiO2 in bauxite rocks is less than 80% and the content of loss on ignition is greater than 15%. This indicates that the bauxite ores is significantly different from bauxite rocks. Combined with previous studies, this paper suggests the formation process of bauxite ores is that under the suitable climatic conditions, the sandshale of the Hanjiadian Formation (the ore-forming mother rocks) was weathering and leaching, then formed weathering residues and clay minerals (mainly kaolinite) which enriched in Al, Ti and other inert elements. After migrated to lakes basin environment, the clay minerals continually lost silicon and iron, enriched in aluminum and formed bauxite rocks. Finally, under the processes of deep buried compaction, diagenesis and mineralization, these clay minerals further lost silicon and iron, enriched in aluminum, the industrial bauxite ores formed in the Middle Permian.

Abstract:The tectonic subsidence history of the Ganluo were reconstructed by using apatite fission-track, Zircon fission-track and vitrinite reflectance data of clastic rock, and correlative restriction on preservation of Zn-Pb Deposit in Ganluo was discussed. Three stages could be compartmentalized as follows: (1) During Late Triassic epoch, influenced by the subduction of the East Tethys Ocean basin, the tectonic environment of Ganluo area changed into paraforeland basin, and the buried depth stara increased rapidly, with the incremental quantity more than 7.6km. (2) Early Jurassic-Paleogene, at this stage, the tectonic regime of Ganluo area transformed and the stara uplifted discontinuously and slowly, the average uplift rate is no more than 32.7m/Ma; (3) Since the beginning of Neogene epoch, the stara of Ganluo uplift quickly, the uplift amplitude in the Northern of Ganluo is more than the Southern, the average uplift rate is more than 295m/Ma from 25.5Ma to 10.3Ma and more than 667 m/Ma from 6Ma up to now. The rapid uplift stage of Ganluo is earlyer than that of Mabian and Lincang, and significantly later than that of Western Panzhihua, this uplift feature is coincide with the outward propagation and growth deformation of tibetan plateau, which is is characterized by multistage coeval and disequilibrium developments. The results of tectonic subsidence history indicates the deep buried diagenesis after mineralization is significant for the preservation of Primary lead-zinc mine, and affects the current emplacement depth of ore body.

Abstract:The sedimentary environment of middle Permian Zhesi Formation in Suolun area was studied on the basis of lithology and sedimentary structure, in combination with the content and ratios of trace elements as well as geochemical parameters of saturated hydrocarbon, then to discuss relative change of sea-level and the evidence for evaluation of oil/gas geologic conditions of Carboniferous-Permian was provided. It indicates that Zhesi Formation mainly belongs to marine sedimentary environment under the condition of warm-humid climate and semi-salt water; the range of palaeosalnity is 18.55‰~28.72‰, The paleosalinity and the change of water depth are showed by the trace elements and their ratios, which are impacted by the change of sea-level. Palaeosalinity and relative change of sea- level has a good correlation with sedimentary facies evolution. Using the quantitative calculation Palaeosalinity and the values which reflect the paleosalinity and the water depth of Sr/ Ba, B/Ga and Rb/ K ,the curve of relative change of sea-level of Zhesi Formation was established. The Zhesi Formation had undergone two transgression-regression cycles and the transgressions take place in the bottom and middle part of Zhesi Formation. According to sedimentary facies analysis and the geochemical index, showed that main body of Zhesi Formation was formed in an neritic shelf environment characterized by oxygen deficient and reductive conditions ,which is conducive to the preservation of organic matter and development of hydrocarbon source rock.

Abstract:Based on the fact that field geological observations, works to expose and geophysical exploration, discovery is located in the North China block before the southern edge of East Qinling 215.6Ma the ruins of an ancient earthquake's epicenter. The studies show that the the earthquake ruins formation depth greater than 10km the MS magnitude greater than 7. Geological, geophysical and engineering to expose the to combine rock geochemistry, isotope tracer isotope dating, REE and trace element characteristics analysis showed that the earthquake ruins by magma differentiation gas-liquid fluid to accumulate enormous pressure cryptoexplosion the fracture within formation.Focal discovery of the ruins and the formation mechanism of understanding of the significance of: the initial recognition of the presence of magmatic gas-liquid cryptoexplosion causes earthquakes, and thus improve the cause of the earthquake is tectonic earthquake causes explain ways to explore and improve the earthquake prediction; overcome seismogenesis research in theseismic source is not visible and not enter into the problem, and for the earthquake causes even earthquake prediction exploring direct observation of the focal entity. The earthquake ruins, the remains of the ruins of a focal, and is likely to be found so far, including a focal entity, the focal depth of the era of seismic intensity (magnitude) occurred, including elements of the most complete earthquake epicenter ruins.

Abstract:The mantle derived magmatogenetic gold deposit in western Shandong area could be defined to the gold deposit related to Mesozoic intrusions. Intrusive rocks relating to gold mineralization are mainly intermediate and alkaline rock stocks and dikes occurring along faults or adjacent areas or overlapping areas of different faults. At least some ore forming material was derived from lower crust or upper mantle, or partly from country rocks, in terms of C, H, O, S and Pb isotopic compositions. The mineralization age of each gold deposit in the Luxi area has big difference: The K Ar isotopic age of goldbearing quartz vein is 962Ma; the age of basic rock sills of Jinxing gold deposit in Yiyuan is 141Ma. The both represent the mineralization age of stratiform multimetal deposit. The inferential mineralization age of Jinchang gold deposit in Yinan is about 128~121Ma, based on the Rb Sr isotopic ages of biotite (133±6Ma from early stage skarn and 128±2Ma from late stage skarn). The area with low denudation degree and concealed rock mass and its surrounding is the favorable area for gold prospecting. The main prospecting direction of stratiform fine grained disseminated gold deposit is in the periphery of intrusive bodies, and the prospecting direction of other types of gold is in intrusive bodies or their contact zones. Due to no systematical deep studies on Mesozoic intrusions in this area, there have no precision dating method on the mineralization age. At present, no feasible method of mineralization age of Guilaizhuang gold deposit in Pingyi is available.