Some aspects of excellent marine source rock formation:implications on enrichment regularity of organic matter in continental margin basins

Through the analysis of ocean organisms, the distribution characteristics and enrichment of organic matters in modern marine sediments and ancient marine strata, this paper shows that the main factors influencing the formation of excellent marine source rocks are the paleoclimate, biologic productivity, terrestrial organic matter, oxidation–reduction environment, sedimentation rate, and the type of the basin. In addition to those factors,high biologic productivity or high content of terrestrial organic matter input is a requirement for the enrichment of the organic matter in a marine environment. Reducing environment was favorable for organic matter accumulation and preservation in depositing and early diagenesis stage, which is an important element for the formation of high-quality marine source rocks. Paleoclimate also influences the marine source rocks formation, as humid subtropical and tropical climates are the most favorable regimes for the formation of marine source rocks. Wind transports some vascular plant materials into the marine environment. Furthermore, upwellings driven by steady wind can cause high biologic productivity, thus formingorganic-C-rich mud. Suitable sedimentation rate is beneficial for marine organic matter accumulation. Moreover, the type of the basin also plays an important role in the development of marine source rocks. Silled basins with a positive water balance often act as nutrient traps, thus enhancing both productivity and organic matter preservations, while in open oceans, organic matter enrichment in sediments has just been found in the oxygen minimum layers.     

Conditions of Petroleum Geology of the Qiangtang Basin of the Qinghai-Tibet Plateau

The Qinghai-Tibet Plateau located in the Tethyan tectonic domain is the best developed region of Mesozoic and Cenozoic marine sediments in China. The Qiangtang basin is the biggest and relatively stable area of the plateau. Triassic and Jurassic hydrocarbon source rocks are extensively distributed in the basin. There exist good dolomite and organic reef reservoirs and mudstone and evaporite cap rocks, as well as well-developed structural traps in the basin; in addition destroyed petroleum traps have been discovered. Therefore, the conditions of petroleum geology in the Qiangtang basin are excellent     

Progress, Problems and Prospects on the Stratigraphy and Correlation of the Kungurian Stage, Early Permian (Cisuralian) Series

The Kungurian Stage is one of the three remaining stages of the Permian that is not yet defined at the base by a Global Stratotype Section and Point (GSSP). The candidate section at the Yuryuzan’River in the Urals yields few conodonts, and contains non-marine sediments near the boundary. The search for a suitable, continuous marine succession is a principal task for the Subcommission on Permian Stratigraphy. The Leonardian, with its type area in the southwest United States, and in objective stratigraphic succession directly beneath the basal Guadalupian Roadian Stage, has priority to serve as a subseries of the Lower Permian. However, distinct provincialism limits the correlation of Leonardian fossil zones with the fusuline-based Tethyan timescale. Conodonts can be correlated in many important regions on opposite sides of Pangea, yet contradictions arise when relating conodont zones with fusuline and ammonoid zones. The different taxonomic philosophies are highly suspected for the cause of the conflicts, but also there are different conodonts from the type Roadian in West Texas. Given that the Pamir and Darvaz in central Asia are difficult to access, further investigations should focus on South China, where abundant fusulines and ammonoids facilitate correlation throughout the Tethyan region, and where conodonts permit correlation with North America.     

High resolution profiles of trace metals in pore waters of marine and riverine sediments assessed by DET and DGT

In polluted aquatic systems, toxic metals are often accumulated in bottom sediments. They are, however, not necessarily stored definitively because diagenetic processs can modify redox, pH and even the amount of complexing ligands, releasing the trace metals back into the pore waters and the water column. Especially the labile metal fraction in the pore waters is important since this is the bioavailable fraction determining the bio-toxicity of the sediments. The goal of our study was therefore to assess, with novel sampling techniques, this bioavailable metal fraction in the pore waters as well as the flux towards the overlying water column. High-resolution profiles of trace metals in pore waters of marine and riverine sediments were assessed by DET （diffusive equilibrium in thin films） and DGT （diffusive gradients in thin films） gel techniques. The DET technique uses a diffusive gel layer that equilibrates with the aquatic system and with this technique the concentrations of total dissolved trace metals are obtained directly. The DGT technique uses an acrylamide diffusive gel backed by a resin gel （Chelex） which binds trace metals. With the DGT technique only labile species of selected metals can be captured. According to the redox potential measurements, the marine sediments were suboxic （200 mV to -220 mV versus Ag/AgCl electrode）, while the riverine sediments were completely anoxic （-160 mV to -220 mV versus Ag/AgCl electrode）. This redox potential was apparently controlling the trace metals species in the pore waters： for example a strong correlation between Mn and Co was found in the riverine sediments （for DET and DGT sampling）, while in the marine sediments trace metals presented various behaviors.     

The Gol-e-Zard Zn-Pb Deposit,Lorestan Province,Iran: a Metamorphosed SEDEX Deposit简

The Gol-e-Zard Zn-Pb deposit is one of several sediment-hosted Zn-Pb deposits found in the central part of the Sanadaj-Sirjan Zone, known as the Isfahan-Malayer belt, western Iran. Mineralization occurs in Upper Triassic to Jurassic phyllites and meta-sandstones. Sphalerite and galena are the most abundant metallic ores, with minor chalcopyrite. Calcite and quartz are the main gangue minerals. Fissure filling, replacement textures and especially mineralized faults, suggest an epigenetic stage in the Gol-e-Zard deposit formation. Geochemical studies of mineralized rocks show high concentrations of Zn, Pb and Cu,（Zn and Pb 〉 10000 ppm and Cu average 3000 ppm）. LREE enrichment（LREE〉HREE, La/Lu average 1.44） and positive Eu anomalies（Eu/Eu＊〉1 average 1.67） indicate reducing conditions during the deposition of deposit. However, some samples do not display negative Ce anomalies, which indicate that localized oxidizing conditions are also present. This study indicates that the Gol-e-Zard deposit formed due to circulating hydrothermal fluids in a marine environment. A SEDEX-type genesis, which is defined by circulating hydrothermal fluids through sediments in a marine environment, and syngenetic precipitation of Zn and Pb sulphides, is suggested for the Gol-e-Zard deposit. Emplacement of some granitoid intrusions such as the Aligudarz granitoid intrusion remobilized mineralizing fluids and metamorphosed the Gol-e-Zard deposit.     

Geological Conditions and Prospect Forecast of Shale Gas Formation in Qiangtang Basin,Qinghai-Tibet Plateau

The presence of shale gas has been confirmed in almost every marine shale distribution area in North America.Formation conditions of shale gas in China are the most favorable for marine,organic-rich shale as well.But there has been little research focusing on shale gas in Qiangtang Basin,Qinghai-Tibet Plateau,where a lot of Mesozoic marine shale formations developed.Based on the survey results of petroleum geology and comprehensive test analysis data for Qinghai-Tibet Plateau,for the first time,this paper discusses characteristics of sedimentary development,thickness distribution,geochemistry,reservoir and burial depth of organic-rich shale,and geological conditions for shale gas formation in Qiangtang Basin.There are four sets of marine shale strata in Qiangtang Basin including Upper Triassic Xiaochaka Formation （T3x）,Middle Jurassic Buqu Formation （J2b）,Xiali Formation （J2x） and Upper Jurassic Suowa Formation （J3s）,the sedimentary types of which are mainly bathyal-basin facies,open platform-platform margin slope facies,lagoon and tidal-fiat facies,as well as delta facies.By comparing it with the indicators of gas shale in the main U.S.basins,it was found that the four marine shale formations in Qiangtang Basin constitute a multi-layer distribution of organic-rich shale,featuring a high degree of thickness and low abundance of organic matter,high thermal evolution maturity,many kinds of brittle minerals,an equivalent content of quartz and clay minerals,a high content of feldspar and low porosity,which provide basic conditions for an accumulation of shale gas resources.Xiaochaka Formation shale is widely distributed,with big thickness and the best gas generating indicators.It is the main gas source layer.Xiali Formation shale is of intermediate thickness and coverage area,with relatively good gas generating indicators and moderate gas formation potential.Buqu Formation shale and Suowa Formation shale are of relatively large thickness,and covering a small area,with poor gas generating indicators,and limited gas formation potential.The shale gas geological resources and technically recoverable resources were estimated by using geologic analogy method,and the prospective areas and potentially favorable areas for Mesozoic marine shale gas in Qiangtang Basin are forecast and analyzed.It is relatively favorable in a tectonic setting and indication of oil and gas,shale maturity,sedimentary thickness and gypsum-salt beds,and in terms of mineral association for shale gas accumulation.But the challenge lies in overcoming the harsh natural conditions which contributes to great difficulties in ground engineering and exploration,and high exploration costs.     

The Cretaceous System in China

This paper provides an outline of Cretaceous stratigraphy and paleogeography in China, which is based on rich data obtained from recent researches. Cretaceous deposits are widespread in China. Most strata are of nonmarine origin and marine sediments occur only in Tibet, western Tarim Basin of Xinjiang, Taiwan and limited localities of eastern Heilongjiang. All deposits are rich in fossils and well-constrained biostratigraphically. The stratigraphic successions of different regions are illustrated, and general stratigraphic division and correlation have been introduced. The marine deposits are described in the Tibetan Tethys, Kashi-Hotan Region of Xinjiang, eastern Heilongjiang, western Yunnan and Taiwan; the nonmarine deposits are outlined from northeast China, southeast China, southern interior China, southwest China, the Shaanxi-Gansu-Ningxia region, and northwestern China intermontane basins. The sedimentary facies and paleogeography are diversified. In Tibet the basin evolution is largely related to the subduction and collision of the Indian Plate against the Eurasian Continent, and shows a tectonic evolution in the Cretaceous. Foraminifera are a dominant biota in the Tibet Tethys. Nonmarine sediments include variegated and red beds, coal- or salt-bearing horizons, and volcanic rocks. These deposits contain diverse and abundant continental faunas and floras, as well as important coal and oil resources. The Cretaceous stratigraphy and paleogeography in China have presented a foundation for geological studies.     

Minerogenetic Mechanism of the Songxi Silver—Antimony Deposit of Northeastern Guangdong—Ore—Controlling Role of Organic Matter

Organic geochemistry and comparisons of characteristics of the organic matter in wall rocks of the ore-controlling strata and ores of the Lower Jurassic Songling black shale formation and the related Songxi silver-antimony deposit of northeastern Guangdong have been studied in this paper.The results show that the Lower Jurassic Songling shale formation is a suite of biologic-rich and organic-rich ore-bearing marine sedimentary rocks.Micro-components of the organic matter in the Songling black shale formation consists primarily of algae,amorphous marine kerogen,solid bitument,and pyrobitument.The thermal evolution of organic matter is at the over-maturity stage.There is a general positive correlation between total organic carbon(CO)and metallogenetic elements such as Ag and Sb in the black shale formation.Organic matter in the host rocks in the Songxi ore deposit played a role in controlling the silver-antimony depositing environment during the forming process of the black shale ore-bearing formation.In the absence of vitrinite,the relative level of thermal maturity calculated by solid bitument reflectance indicates that the ore-forming temperatute of the Songxi silver-antimony deposit was about 150-170℃,which was considered as an epithermally reworked ore deposit.The roles of organic matter in the formation of the Sonxi ore deposit are a primitive accumulation of the metallogenetic elements(Ag,Sb) in the sea-water cycle system for ore source and a concentration of metals by ion exchange of chelation as well as reductionn of the oxidzed metals.     

Source and Enrichment Mechanism of Lithium in the Triassic Argillaceous Marine Sediments from Huangjinkou, Sichuan, China

In the Triassic marine sediments, an obvious enrichment of lithium has been found. The source and enrichment mechanism of lithium is unknown. Here, we report trace and rare earth element and isotope analyses for Triassic sedimentary samples from core ZK601, recovered from the Huangjinkou anticline in the Xuanhan basin. Lithium concentrations from the Leikoupo and Jialingjiang formations are much higher than the average concentrations in the crust of eastern China and in other marine sediments. Lithium concentrations are highest at depths of 3300–3360 m (in argillaceous marine sediments), and Li is positively correlated with Rb, Ga, Zr, Nb and other trace elements. The range of δ7Li values in our samples is consistent with that in other Triassic marine carbonate rocks. Lithium concentrations and isotope ratios are negatively correlated in the argillaceous dolomite samples at depths of 3300–3360 m. We compared the results in this study with trace and rare earth elements in the clay from Sichuan and Chongqing, and propose that the clay in the argillaceous marine evaporites from Huangjinkou formed via the hydrolysis of volcanic ash during Early–Middle Triassic volcanic eruptions into brine basins, during which clay adsorbed Li from the brine and formed Li-rich argillaceous dolomites. The addition and hydrolysis of volcanic ash in the evaporative brine is also related to the formation of a new type of polyhalite.     

Development of highly sensitive analytical methods for radionuclides in marine environmental studies

The determination of natural and artificial radionuclides, such as Th, U and Pu isotopes, in the marine environmental studies is important and has been an active research field in the environmental analytical geochemistry. For example, uranium isotope ratios give information regarding the source of the uranium in the environment, and are important for studying its biogeochemical behavior, while thorium isotope （^230Th） and Pu isotopes are good tracers for particle scavenging process study in the ocean. Due to the extremely low concentrations of these radionuclides in the marine environment, the accurate analysis of these radionuclides is still a challenging task. In this presentation, we will present the recent development of highly sensitive analytical methods for ^230Th, ^234U, ^235U, ^238U, ^239Pu and ^240Pu and their isotope ratios （^234U/^238U, ^235U/^238U, ^240Pu/^239Pu） in radionuclides in marine environmental samples, such as seawater, sediments, settling particles, using quadrupole and sector field ICP-MS. Applications of the radionuclide analysis in the marine environmental studies, such as the radioactivity environmental monitoring,     

Stratigraphy of the Triassic?Jurassic Boundary Successions of the Southern Margin of the Junggar Basin, Northwestern China

The Triassic?Jurassic (Tr?J) boundary marks a major extinction event, which (~200 Ma) resulted in global extinctions of fauna and flora both in the marine and terrestrial realms. There prevail great challenges in determining the exact location of the terrestrial Tr?J boundary, because of endemism of taxa and the scarcity of fossils in terrestrial settings leading to difficulties in linking marine and terrestrial sedimentary successions. Investigation based on palynology and bivalves has been carried out over a 1113 m thick section, which is subdivided into 132 beds, along the Haojiagou valley on the southern margin of the Junggar Basin of the northern Xinjiang, northwestern China. The terrestrial Lower Jurassic is conformably resting on the Upper Triassic strata. The Upper Triassic covers the Huangshanjie Formation overlaid by the Haojiagou Formation, while the Lower Jurassic comprises the Badaowan Formation followed by the Sangonghe Formation. Fifty six pollen and spore taxa and one algal taxon were identified from the sediments. Based on the key-species and abundance of spores and pollen, three zones were erected: the Late Triassic (Rhaetian) Aratrisporites?Alisporites Assemblage, the Early Jurassic (Hettangian) Perinopollenites?Pinuspollenites Assemblage, and the Sinemurian Perinopollenites?Cycadopites Assemblage. The Tr?J boundary is placed between bed 44 and 45 coincident with the boundary between the Haojiagou and Badaowan formations. Beds with Ferganoconcha (?), Unio?Ferganoconcha and Waagenoperna?Yananoconcha bivalve assemblages are recognized. The Ferganoconcha (?) bed is limited to the upper Haojiagou Formation, Unio?Ferganoconcha and Waagenoperna?Yananoconcha assemblages are present in the middle and upper members of the Badaowan Formation. The sedimentary succession is interpreted as terrestrial with two mainly lake deposit intervals within Haojiagou and Badaowan formations, yielding fresh water algae and bivalves. However, the presence of brackish water algae Tasmanites and the marine?littoral facies bivalve Waagenoperna from the Badaowan Formation indicate that the Junggar Basin was influenced by sea water caused by transgressions from the northern Tethys, during the Sinemurian.     

The Gol-e-Zard Zn-Pb Deposit,Lorestan Province,Iran: a Metamorphosed SEDEX Deposit

The Gol-e-Zard Zn-Pb deposit is one of several sediment-hosted Zn-Pb deposits found in the central part of the Sanadaj-Sirjan Zone, known as the Isfahan-Malayer belt, western Iran. Mineralization occurs in Upper Triassic to Jurassic phyllites and meta-sandstones. Sphalerite and galena are the most abundant metallic ores, with minor chalcopyrite. Calcite and quartz are the main gangue minerals. Fissure filling, replacement textures and especially mineralized faults, suggest an epigenetic stage in the Gol-e-Zard deposit formation. Geochemical studies of mineralized rocks show high concentrations of Zn, Pb and Cu, (Zn and Pb > 10000 ppm and Cu average 3000 ppm). LREE enrichment (LREE>HREE, La/Lu average 1.44) and positive Eu anomalies (Eu/Eu*>1 average 1.67) indicate reducing conditions during the deposition of deposit. However, some samples do not display negative Ce anomalies, which indicate that localized oxidizing conditions are also present. This study indicates that the Gol-e-Zard deposit formed due to circulating hydrothermal fluids in a marine environment. A SEDEX-type genesis, which is defined by circulating hydrothermal fluids through sediments in a marine environment, and syngenetic precipitation of Zn and Pb sulphides, is suggested for the Gol-e-Zard deposit. Emplacement of some granitoid intrusions such as the Aligudarz granitoid intrusion remobilized mineralizing fluids and metamorphosed the Gol-e-Zard deposit.     

Remobilization of Iodine in Marine Sediments During Early Diagenesis

Based on the sedimentary geochemical studies of the Antarctic Ocean and the various geochemical parameters available,this paper deals with the process of emobilization of iodine in marine sediments during early diagenesis.The results showed that the process is not always controlled completely by organic matter as was expected previously.On average the adsorption and oxide phases of iodine account respectively for 23% and 32% of the total in continental-shelf and hemipelagic surficial sediments.Chemical analysis has revealed that the upward diffusion flux and redox conditions would play an important role in the concentration of iodine in the surface sediments.And the species of iodine in the surfial sediments characteristic of high I/Corg ratios would bepredominated by the oxide and adsorption phases.As experimentally evidenced,it is the early diagenetic remoibilization of iodine associated with the oxide and adsorption phases that led to the decrease of I/Corg with increasing depth.Calculations suggested that the diffusion flux of iodine from the deep parts of te sedimentary columum upwards is on the same order of magnitude as the deposition flux of it from sea water.This may be one of the important factors leading to the depletion of iodine in sedimentary rocks.On the basis of the above discussion and calculations the author has proposed a model for the remobilization of iodine in marine sediments during early diagenesis.     

An Updated Review of the Middle-Late Jurassic Yanliao Biota: Chronology, Taphonomy, Paleontology and Paleoecology

The northeastern Chinese Yanliao Biota (sometimes called the Daohugou Biota) comprises numerous, frequently spectacular fossils of non-marine organisms, occurring in Middle-Upper Jurassic strata in western Liaoning, northern Hebei, and southeastern Inner Mongolia. The biota lasted for about 10 million years, divided into two phases: the Bathonian-Callovian Daohugou phase (about 168-164 million years ago) and the Oxfordian Linglongta phase (164-159 million years ago). The Yanliao fossils are often taphonomically exceptional (many vertebrate skeletons, for example, are complete and accompanied by preserved integumentary features), and not only are taxonomically diverse but also include the oldest known representatives of many groups of plants, invertebrates, and vertebrates. These fossils have provided significant new information regarding the origins and early evolution of such clades as fleas, birds, and mammals, in addition to the evolution of some major biological structures such as feathers, and have demonstrated the existence of a complex terrestrial ecosystem in northeast China around the time of the Middle-Late Jurassic boundary.     

A New Species of Ginkgo with Male Cones and Pollen Grains in situ from the Middle Jurassic of Eastern Xinjiang, China

Well-preserved Ginkgo pollen organs are analyzed from the Middle Jurassic Xishanyao Formation of the Turpan–Hami Basin, Xinjiang Uygur Autonomous Region, northwestern China, and are described as a new species, Ginkgo hamiensis Z.X. Wang et B.N. Sun sp. nov. The immature male cones are cylindrical and catkin-like, with two longitudinal stripes on the stalk. The pollen sacs are shaped like a long oval with two pollen sacs fused together for each microsporophyll, and the microsporophyll tip is a triangular cystidium. The pollen grains are oblong or fusiform and monocolpate; both ends are blunt or sharp. By comparison with previously reported fossil records of Ginkgo plants, we determined that the current fossils are different from all other reported species; thus, the present fossil is referred to as a new species of Ginkgo. The reproductive organs of the Ginkgo fossils described herein can provide valuable information for the study of Ginkgo plants. Further, there are two probable evolutionary trends in the Ginkgo pollen cones. One trend is that the number of pollen sacs changed from three or four during the Jurassic and Cretaceous to two at the present day; the other is that the number of pollen sacs has remained two from the Middle Jurassic to the present day. In addition, the pollen cones described herein are similar to the pollen cones of the extant Ginkgo, which strongly indicates that the morphology of Ginkgo plants may have remained highly conserved over millions of years.     

The Cenomanian—Turonian Anoxic Event in Southern Tibet：A Study of Organic Geochemistry

The Cenomanian-Turonian oceanic anoxic event(C/T OAE) is developed in southern Tibet.Organic geochemical study of the Cenomanian-Turonian sediments from the Gamba and Tingri aress shows that the mid-Cretaceous black shales in southern Tibet are enriched in organic carbon.Te molecular analyses of organic matter indicate marine organic matter was derived from algae and bacteria.In the Gamba area,the organic matter is characterized by abundant tricyclic terpanes and pregane,which are predominant in 191 and 217 mass chromatograms,respectively,Pristane/phytane(Pr/Ph)ratios in the C/T OAE sediments are less than 1, demonstrating the domination of phytane.The presence of carotane can be regarded as a special biomarker indicating oxygen depletion in the C/T OAE sediments in the Tethyan Himalayas.In anoxic sediments,β-carotane and γ－carotane are very abundant.The β-and γ-carotane ratios relative to nC17 in the Cenomanian-Turonian anoxic sediments vary from 32.28-42.87and 5.10-11.01.     

New Jurassic Fossil True Bugs of the Pachymeridiidae(Hemiptera:Pentatomomorpha)from Northeast China

Four new fossil genera and species of true bugs from the family Pachymeridiidae, Beipiaocoris multifurcus, Bellicoris mirabilis, Nitoculus regiUus, and Viriosinervis stolidus, are described. New specimens were collected from the Middle and Upper Jurassic non-marine sedimentary strata from the Jiulongshan and Yixian Formations of northeast China. The species Karatavocoris asiatica Becker-Migdisova, 1963, which was considered to be a member of the family Coreidae is transferred to the Pachymeridiidae. A new map of all known and newly discovered fossil pachymeridiid localities is given. The diagnosis of the family is modified.     

Geochemistry of fine-grained sediments of the upper Cretaceous to Paleogene Gosau Group （Austria, Slovakia） Implications for paleoenvironmental and provenance studies

Bulk rock geochemistry of 169 fine-grained sediment samples of the upper Cretaceous to Paleogene Gosau Group（Northern Calcareous Alps,Austria and Slovakia） from borehole and outcrop localities was performed to separate non-marine and marine deposits.Geochemical characteristics of different Gosau depositional systems,basins and sediment provenance using major-,trace-,and rare earth elements were also investigated.Geochemical proxies such as boron concentrations were tested for seeking the possibilities of paleosalinity indicators.Due to the fact that several pelagic sections are represented by extremely low boron contents.B/Al^* ratios are recognized as more robust and differentiate reliably between marine（mean:160±34） and non-marine（mean:133±33） samples.Using statistical factor analysis,hemipelagic to pelagic samples from the Gieβhbl Syncline and Slovakian equivalents can be differentiated from marginal-marine to non-marine samples from the Grnbach and Glinzendorf Syncline related to terrigenous（SiCh.Al₂O₃,K₂O,Th,Rb,Zr and others） and pelagic indicative elements （CaO,Sr,TOT/C and B/Al^*）.A clear indication for ophiolitic provenance is traced by high amounts of chromium and nickel.Only non-marine successions of the Glinzendorf Syncline show higher Cr and Ni concentrations（up to 250 and 400 ppm,respectively） and enriched Cr/V and Y/Ni ratios trending to an ultramafic source.     

The Shishugou Fauna of the Middle–Late Jurassic Transition Period in the Junggar Basin of Western China

The Middle–Late Jurassic transition period is a critical period for the evolution of terrestrial vertebrates, but the global fossil record from this time is relatively poor. The Shishugou Fauna of this period has recently produced significant fossil remains of dinosaurs and other vertebrate groups, some representing the earliest known members of several dinosaurian groups and other vertebrate groups and some representing the best-known specimens of their group. These discoveries are significant for our understanding of the origin and evolution of several vertebrate lineages. Radiometric dating indicates that the fauna is aged approximately 159–164 Ma. Comparisons with other similarly-aged terrestrial faunas such as Shaximiao and Yanliao show both taxonomic similarities and differences between these faunas and indicate that the Junggar deposits might have preserved the most complete vertebrate fossil record for a Middle–Late Jurassic Laurasian terrestrial fauna.     

Geological characteristics and metallogenic prospect of marine volcanic rock-type copper deposits in eastern Kunlun Mountains area,Xinjiang

The Katelixi Cu-Zn deposit is a marine volcanic rock-type copper deposit discovered for the first time in the Tokuzidaban Group in eastern Kunlun Mountains area. It is hosted in the Lower Carboniferous Tokuzidaban Group volcanic strata. The orebodies are obviously controlled by the strata and their ore-bearing rocks are a suite of greyish-green mafic tuffs, generally parallel-stratiform, stratoid and lenticular in form, occurring in limestone as well as in the contact between limestone and carbon-bearing siltstone. This ore deposit possesses distinct characteristics of marine volcanic rock sedimentaion. The geological, petrochemical and REE characteristics of its occurrence pro-vide strong evidence suggesting that this deposit is of marine volcanic rock sedimention origin, basically identical to those of some typical marine volcanic rock-type copper deposits in Xinjiang and other parts of China. Marine vol-canic rocks are well developed in the Lower Carboniferous Tokuzidaban strata in eastern Kunlun Mountains area. In addition to this deposit, we have also found a number of copper polymetallic ore deposits or occurrences in associa-tion with marine volcanc activities in many places where there is a good metallogenic prospect. A breakthrough in the understanding of ore prospecting and genesis has not only filled up the gap in prospecting this type of ore depos-its in this area, but also is of great significance in directing exploration of this type of ore deposits in this area.