Paleogeographical Distribution of Mesozoic Palaeontinidae (Insecta, Hemiptera) in China with Description of New Taxa

Until now, all Chinese palaeontinids have come from northern China and are more diverse than any other hemipterous insects in the Mesozoic. Most palaeontinids have been discovered from the area encompassing northern Hebei, the Ningcheng area of Inner Mongolia and western Liaoning. The difference in ubiquity of fossil records between northern and southern China is probably related to taphonomical and collecting bias. Records of Early and Late Jurassic palaeontinids are very scarce. The highest diversity of palaeontinid species occurs in the Middle Jurassic of Daohugou Lagerstfitte. Early Cretaceous palaeontinids of China are restricted to the typical distribution of Jehol Biota. Palaeontinodes sp. is described from the Lower Cretaceous Yixian Formation of Yangshuwanzi, Inner Mongolia and is the only Palaeontinodes specimen from the Cretaceous. Plachutella exculpta Zhang, 1997 from the Lower Jurassic Badaowan Formation of Karamai, Xinjiang is re-described and some previously reported species of this genus are discussed.

Pre-Cryogenian integrative stratigraphy,biotas,and paleogeographical evolution of the Qinghai-Tibetan Plateau and its surrounding areas

The composition and geological evolution of pre-Cryogenian material in the Tibetan Plateau and its surrounding areas have played an important role in studying the formation and evolution of early supercontinents on Earth.This paper systematically summarizes the characteristics of pre-Cryogenian sedimentation,paleontology,magmatism,and metamorphism in the Tibetan Plateau and its surrounding areas.Based on existing data,the records of pre-Cryogenian sedimentation and paleontology are mainly concentrated in the Meso-Neoproterozoic,with relatively few records from the Paleoproterozoic or earlier.The oldest geological record is the Hadean detrital zircons in the metamorphosed sedimentary rocks of the Himalaya and Qamdo areas(ca.4.0 Ga).The Tibetan Plateau and surrounding areas preserve records related to the formation and evolution of the Kenor supercraton,and the Columbia,Rodinia,and Gondwana supercontinents.Pre-Cryogenian basements can be divided into three types:Tarim-,Yangtze-,and Lhasa-type.The Tarim-type basement has a paleogeographic affinity with the northern margins of the Australian and Indian continents and lacks detrital zircon age peaks and magmatic-metamorphic records related to the Rodinia assembly(ca.1.3-0.9 Ga).The Yangtze-type basement records volcanic activity related to global cooling in the latest pre-Cryogenian period and contains Meso-Neoproterozoic stromatolite and micropaleoflora fossils,as well as magmaticmetamorphic records related to Rodinia assembly(ca.1.1-1.0 Ga).The Lhasa-type basement is characterized by Neoproterozoic rift-related sediment records(ca.900 Ma)and high-pressure metamorphic events(ca.650 Ma),with a prominent peak of detrital zircon ages of ca.1.2-1.1 Ga.It is likely to have a paleogeographic affinity with the African continent.

EVOLUTION AND DIFFERENTIATION OF THE PHYSICO-EOGRAPHICALENVIRONMENT OF THE QINGHAI-XIZANG (TIBETAN) PLATEAU

The intense uplift of the Qinghai-Xizang Plateau givesrise to drastic changes of natural environment and distinctdifferentiation of the Plateau proper. This paper focuses on theevolution of subtropical environment at low altitude to frigidenvironment at high altitude of the region since Pliocene and thechanges effected by cold-warm amplitude bf global change. Bycomparative study on the structure-type of the altitudinal belt, adistributional model diagram with close relevance to highlanduplift effect has been generalized. Based on regjonaldifferentiation of the Qinghai-Xizang Plateau, a number ofstriking geo-ecological phenomena such as moisture corridor, dryvalleys and high cold-arid core area are investigated anddiscussed.

How many sutures in the southern Central Asian Orogenic Belt:Insights from East Xinjiang-West Gansu(NW China)?

How ophiolitic mèlanges can be defined as sutures is controversial with regard to accretionary orogenesis and continental growth.The Chinese Altay,East junggar,Tianshan,and Beishan belts of the southern Central Asian Orogenic Belt（CAOB） in Northwest China,offer a special natural laboratory to resolve this puzzle.In the Chinese Altay,the Erqis unit consists of ophiolitic melanges and coherent assemblages,forming a Paleozoic accretionary complex.At least two ophiolitic melanges（Armantai,and Kelameili） in East Junggar,characterized by imbricated ophiolitic melanges,Nb-enriched basalts,adakitic rocks and volcanic rocks,belong to a Devonian-Carboniferous intra-oceanic island arc with some Paleozoic ophiolites,superimposed by Permian arc volcanism.In the Tianshan,ophiolitic melanges like Kanggurtag,North Tianshan,and South Tianshan occur as part of some Paleozoic accretionary complexes related to amalgamation of arc terranes.In the Beishan there are also several ophiolitic melanges,including the Hongshishan,Xingxingxia-Shibangjing,Hongliuhe-Xichangjing,and Liuyuan ophiolitic units.Most ophiolitic melanges in the study area are characterized by ultramafic,mafic and other components,which are juxtaposed,or even emplaced as lenses and knockers in a matrix of some coherent units.The tectonic settings of various components are different,and some adjacent units in the same melange show contrasting different tectonic settings.The formation ages of these various components are in a wide spectrum,varying from Neoproterozoic to Permian.Therefore we cannot assume that these ophiolitic melanges always form in linear sutures as a result of the closure of specific oceans.Often the ophiolitic components formed either as the substrate of intra-oceanic arcs,or were accreted as lenses or knockers in subduction-accretion complexes.Using published age and paleogeographic constraints,we propose the presence of （1） a major early Paleozoic tectonic boundary that separates the Chinese Altay-East Junggar multiple subduction systems of the southern Siberian active margin from those of the northern Tarim;and （2） a major Permian suture zone that separates the Tianshan-Beishan from the northern active margin of the Tarim Craton.These new observations and interpretations have broad implications for the architecture and crustal growth of central Asia and other ancient orogens as well.

Chinese Continental Blocks in Global Paleocontinental Reconstruction during Paleozoic and Mesozoic

The Cambrian to Cretaceous paleomagnetic data from Chinese continental and adjacent blocks were collected using principles to obtain reliable and high-precision paleomagnetic data and to pay attention to the similarity of paleobiogeography and the coordination of tectonic evolution.The Chinese continental blocks were laid up on the reconstruction of proposed global paleocontinents with almost the same scale.Thus,it can be clearly recognized that the global continents,including Chinese continental blocks,range along latitudes on the southern side of the equator during the Early Paleozoic. In the Paleozoic,Chinese continental blocks were still located among the Laurentia,Siberia and Gondwana plates,following the fast moving of the Siberia Plate northwards,the amalgamation in a north-south direction at the western parts of the Laurentia and Gondwana plates,and the Iapetus and Rheic Oceans were subducted,eventually to form a uniform Pangea in the Late Paleozoic.The Australian and Indian plates of Eastern Gondwana moved and dispersed gradually southwards, continued to extend the Paleo-Tethys Ocean.The Chinese continental and adjacent blocks were still located in the Paleo-Tethys Ocean,preserved the status of dispersion,gradually moving northwards, showing characteristics of ranging along a north-south orientation until the Permian.In addition,a series of local collisions happened during the Triassic,and consequently most of the Chinese continental blocks were amalgamated into the Pangea,except for the Gangdise and Himalayan blocks. There was a counter-clockwise rotation of the Eastern Asian continent in the Jurassic and northwards migration of the Chinese continent in varying degrees during the Cretaceous,but the Himalayan and Indian plates did not collide into the Chinese continent during this period.

New Schizolepis Fossils from the Early Cretaceous in Inner Mongolia, China and its Phylogenetic Position

Three Schizolepis species collected from the Lower Cretaceous layer of the Huolinhe Basin, Inner Mongolia, China are described. These fossils are Schizolepis longipetiolus Xu XH et Sun BN sp. nov., which is a new species, Schizolepis cf. heilongjiangensis Zheng et Zhang, and Schizolepis neimengensis Deng. The new species is a well-preserved female cone, slender and cylindrical in shape. The seed-scale complexes have long petioles and are arranged on the cone axis loosely and helically. The seed scales are divided into two lobes from the base. Each lobe is semicircular or elongate ligulate in shape, widest at the middle or the lower middle part, with an obtuse or bluntly pointed apex. The inner margin is almost straight and the outer margin is strongly arched. On the surface of the lobe, there are longitudinal and somewhat radial striations from the base to the margin. The seed is borne on the adaxial surface at the base or middle of each lobe. Schizolepis was estabfished in 1847, and, although more than twenty species have been discovered and reported, its phylogenetic position is controversial because of the imperfection of fossils. Most authors have considered there to be a close evolutionary relationship between Schizolepis and extant Pinaceae. Here, we analyze characteristics and compare Schizolepis with Picea crassifolia Kom, which is morphologically most similar to Schizolepis. The results indicate that the genus probably has a distant evolutionary relationship with extant Pinaceae. A detailed statistical analysis of the global paleogeographic distribution of Schizolepis showed that all the fossils of this genus appeared in strata ranging from the Upper Triassic to the Lower Cretaceous in the North Hemisphere, being rare in the Upper Triassic and Lower Jurassic, but being very common from the Middle Jurassic to the Lower Cretaceous, and particularly abundant in the Lower Cretaceous. According to the statistical results, we speculate that the genus originated in Europe in the Late Triassic then spread from Europe to Asia between the Late Triassic and the Late Jurassic. In the Early Cretaceous most species existed in China＇s three northeastern Provinces and the Inner Mongolia Autonomous Region and adjacent areas. Combining the paleogeographic distribution of the genus with ancient climatic factors, we deduced that Schizolepis began to decline and became extinct in the Early Cretaceous, and the reason for its extinction is closely related to the icehouse climate during the Early Cretaceous.

Tectonic Evolution and Key Geological Issues of the ProtoSouth China Sea

There are numerous controversies surrounding the tectonic properties and evolution of the Proto-South China Sea(PSCS).By combining data from previously published works with our geological and paleontological observations of the South China Sea(SCS),we propose that the PSCS should be analyzed within two separate contexts:its paleogeographic location and the history of its oceanic crust.With respect to its paleogeographic location,the tectonic properties of the PSCS vary widely from the Triassic to the mid-Late Cretaceous.In the Triassic,the Paleo-Tethys and the Paleo-Pacific Oceans were the major causes of tectonic changes in the SCS,while the PCSC may have been a remnant sea residing upon Tethys or Paleo-Pacific oceanic crust.In the Jurassic,the Meso-Tethys and the Paleo-Pacific oceans joined,creating a PSCS back-arc basin consisting of Meso-Tethys and/or Paleo-Pacific oceanic crust.From the Early Cretaceous to the midLate Cretaceous,the Paleo-Pacific Ocean was the main tectonic body affecting the SCS;the PSCS may have been a marginal sea or a back-arc basin with Paleo-Pacific oceanic crust.With respect to its oceanic crust,due to the subduction and retreat of the Paleo-Pacific plate in Southeast Asia at the end of the Late Cretaceous,the SCS probably produced new oceanic crust,which allowed the PSCS to formally emerge.At this time,the PSCS was most likely a combination of a new marginal sea and a remnant sea;its oceanic crust,which eventually subducted and became extinct,consisted of both new oceanic crust and remnant oceanic crust from the Paleo-Pacific Ocean.In the present day,the remnant PSCS oceanic crust is located in the southwestern Nansha Trough.

Control of paleogeographic pattern on sedimentary differentiation of evaporite-carbonate symbiotic system:A case study of the sixth sub-member of Ordovician Majiagou Formation M5 Member in central-eastern Ordos Basin,NW China

The relationship between paleogeographic pattern and sedimentary differentiation of evaporite-carbonate symbiotic system is examined based on logging,core and thin section data,by taking the sixth sub-member of fifth member of Ordovician Majiagou Formation(M56)in the central-eastern Ordos Basin as an example.(1)Seven sub-geomorphic units(Taolimiao west low,Taolimiao underwater high,Taolimiao east low,Hengshan high,East salt low,North slope and Southwest slope)developed in the study area.(2)The“three lows”from west to east developed dolomitic restricted lagoon,evaporite evaporative lagoon and salt evaporative lagoon sedimentary facies respectively,the"two highs"developed high-energy grain beach and microbial mound,and the north and south slopes developed dolomitic flats around land.(3)The paleogeographic pattern caused natural differentiation of replenishment seawater from the northwest Qilian sea,leading to the eccentric sedimentary differentiation of dolomite,evaporite and salt rock symbiotic system from west to east,which is different from the classic“bull's eye”and“tear drop”distribution patterns.(4)As the Middle Qilian block subducted and collided into the North China Plate,the far-end compression stress transferred,giving rise to the alternate highland and lowland in near north to south direction during the sedimentary period of M56 sub-member.(5)Taolimiao underwater high and Hengshan high developed favorable zones of microbial mounds and grain shoals in south to north strike in M56 sub-member,making them favorable exploration areas with great exploration potential in the future.

Cambrian faults and their control on the sedimentation and reservoirs in the Ordos Basin, NW China

Comprehensively utilizing the seismic,logging,drilling and outcrop data,this research studies the characteristics of the Cambrian faults and their control on the sedimentation and reservoirs in the Ordos Basin.The results show that:(1)Three groups of faults striking North-East(NE),near East-West(EW),and North-West(NW)were developed in the Cambrian.The NE and near EW faults,dominated by the normal faults,are the synsedimentary faults and the main faults of the Cambrian.(2)According to the roles of faults in tectonic units and the development scale of the faults,the Cambrian faults can be divided into three grades.The second-grade faults,large in scale,controlled the boundary of the Cambrian sags of the Ordos Basin.The third-grade faults,smaller in scale than the second-grade fault,controlled the high and low fluctuations of local structures.The fourth-grade faults,very small in scale,were adjusting faults developed inside the local tectonic units.(3)The Cambrian faults had strong control on the sedimentation and reservoir of the Cambrian.Controlled by the second-grade and the third-grade faults,the paleogeographical framework of the Cambrian presents combination characteristics of the bulge-sag macro-structures and the high-low differentiation micro-geomorphology.This paleogeographical pattern not only controlled the development of the oolitic beach facies in the Cambrian but also the distribution of high-quality reservoirs.(4)Under the control of the faults,the micro-paleogeomorphological high parts closely adjacent to the margin of the Cambrian sags are the favorable exploration areas.

Magmatism and metamorphism at ca. 1.45 Ga in the northern Gawler Craton: The Australian record of rifting within Nuna(Columbia)

U-Pb monazite and zircon geochronology and calculated metamorphic phase diagrams from drill holes in the northern Gawler Craton, southern Australia, reveal the presence of ca. 1.45 Ga magmatism and metamorphism. Magmatism and granulite facies metamorphism of this age has not previously been recognised in the Gawler Craton. The magmatic rocks have steep LREE-enriched patterns and high Ga/Al values, suggesting they are A-type granites. Calculated metamorphic forward models suggest that this event was associated with high apparent thermal gradients and reached pressures of 3.2 -5.4 kbar and temperatures of 775-815℃. The high apparent thermal gradients may reflect pluton-enhanced metamorphism, consistent with the presence of A-type granites. The recognition of ca. 1.45 Ga tectonism in the northern Gawler Craton is added to a compilation of ca. 1.50 -1.40 Ga magmatism, shear zone reactivation, rift basin development and isotope resetting throughout the South and North Australian Cratons that shows that this event was widespread in eastern Proterozoic Australia. This event is stylistically similar to ca. 1.45 Ga A-type magmatism and high thermal gradient metamorphism in Laurentia in this interval and provides further support for a connection between Australia and Laurentia during the Mesoproterozoic. The tectonic setting of the 1.50-1.40 Ga event is unclear but may record rifting within the Nuna(or Columbia) supercontinent, or a period of intracontinental extension within a long-lived convergent setting.

Paleogeographic Reconstitution and Tangential Tectonic in the Backland of Tunisian Dorsal (Fahs Area: J. Rouas and Ruissate)

The Tunisian Dorsal backland is the Eastern Atlas side of maghrebides. Field data of Fahs area allowed us to develop new interpretations and to characterize the main structural features of the studied devices (Jebel Rouas and Ruissate). Heritage of Zaghouan accident, Triassic salt movements and strike-direction of major synsedimentary faults are the principal causes and results of the skinned and superimposed geometric architecture, generated by the reversed extensional (Jurassic-Cretaceous) tectonics. The actual geometry of Jebel Rouas and Ruissate represents a fault propagation fold, affecting Jurassic and Cretaceous sets. The backland of this thrust fault defines an imbrications structures of Barremian series. Tectonic records activities show the existence of angular unconformities (Oligocene and Eocene series on the Cretaceous sets considered as bedrock), slumps, tectonic breccias and synsedimentary faults are all of them controlled by a deep major accident;N-S to NE-SW and NW-SE. Features of the study area are probably related first;to the blockage of Zaghouan thrust oriented NE-SW in the foreland;then, to the intense halokinetic activity, which facilitates the layers displacement acting as decollment level. The detailed structural and stratigraphic study of Fahs area and its neighbors shows the presence of an intense tangential tectonic during upper Miocene, affecting Meso-Cenozoic sets, because all the structures involved are sealed by Oligocene and Miocene thinned series. This is accentuated by the existence of different sets of decollment at different depths, which are represented by a displacement to the SE through the backland of the Tunisian Dorsal. We define these features as an imbrication and thrusting Out of sequence system.

Dyke Swarms: Keys to Paleogeographic Reconstructions, Preface for IDC7 2016

Focusing on geological,geochemical and geophysical aspects of dykes and related units,the International Dyke Conference(IDC)series was launched in Toronto,Canada in 1985 by Prof.Henry C.Halls(University of Toronto).It has continued approximately every five years with

Paleomagnetic Data and Dyke Swarms Geometries – Important Tools for Precambrian Paleogeographic Reconstructions

There are only two quantitative tools for Precambrian paleogeographic reconstructions–paleomagnetic data and dyke swarms geometries.Paleomagnetic data provide information about paleolatitudes and orientation of rigid

Palaeomagnetic Study on a 1765 Ma Dyke Swarm from Singhbhum Craton: Implications to the Paleogeographic Position of India

The paleogeographic position of India within the Columbia supercontinent during Paleoproterozoic era is still uncertain because of very few reliable,high-quality palaeomagnetic data with precise geochronology.Here we

Sedimentary model reconstruction and exploration significance of Permian He 8 Member in Ordos Basin,NW China

Based on the Late Paleozoic geological background and the latest exploration achievements of the Ordos Basin and North China platform, it is concluded that during the sedimentary period of Permian He 8 Member, the area in concern had multiple material sources, multiple river systems, flat terrain, shallow sedimentary water, widely distributed fluvial facies sand body and no continuous lake area, so alluvial river sedimentary system developed in the whole region. Based on stratigraphic correlation and division, and a large number of drilling and outcrop data, a comprehensive analysis of lithofacies and sedimentary facies types and distribution was carried out to reconstruct the ancient geographic pattern of the He 8 Member sedimentary period. The results of paleogeography restoration show that the area of Ordos Basin was the "runoff area" in the sedimentary slope in the western part of the North China platform during the sedimentary period of He 8 Member, the whole region was mainly alluvial plain sedimentation featuring alternate fluvial facies, flood plain facies and flood-plain lake facies. According to the results of flume deposition simulation experiment, a new sedimentary model of "alluvial river & flood-plain lake" is established, which reveals the genesis of large area gravel sand body in He 8 Member of this area and provides geological basis for the exploration of tight gas in the south of the basin.

Paleogeographic Peculiarities of Potassium and Potassium-Magnesium Salt Generation in the Southeast of the Russian Plate

Permian salt-bearing formation covers a substantial area of the Russian Plate.In some places,it is up to several kilometers thick.The salt-bearing formation contains unique accumulations of potassium and magnesium salts,

Interpretation of Depositional Environment of Fusulinid Bearing Middle Permian Succession of Bolula and Khaja Ghar Formation, Bamian Zone, Central Afghanistan

The study area belongs to the north Afghanistan having complex tectonic setting, because of separation of the Afghanistan plate from Pangea in Early Permian and its subsequent northward journey and collision with Eurasian plate. The rock exposed in the area belongs to Paleozoic, Mesozoic to Quaternary with Proterozoic basement. Particularly the Permian succession of Afghanistan is rich in fusulinids (larger foraminifera), is age diagnostic, provides strong biostratigraphic tool for the Permian deposits, and has paleobiogeographic applications. The Bamian zone of north Afghanistan has good exposure to Middle Permian and is designated as Bolula and Khaja Ghar Formation is undertaken in this study. The Bolula Formation overlies the greenschist and basalts, composed mainly of carbonate rocks (Dolostone and limestone), having massive limestone, with some quartz and secondary calcite vein in the succession. The intermittent siliciclastic wedges within the carbonate succession are identified as input within the platform with tectonic pulses in the hinterland. Bolula and Khaja Ghar succession is divided into 8 lithofacies ( Facies A to H) and 6 carbonate Facies viz. Sparry calcites limestone, Micritic limestone, Fossiliferous limestones (Biomicrite), Peloidal limestone (Fecal pellets), Interlaminated micritic and sparite limestone, and sandy limestone (micritic). The Bolula and Khaja Ghar Formation in the Bamian area have deposited in a shallow marine shelf environment because of predominance of carbonate rocks and presence of shallow-water marine fossils including fusulinids, small benthic foraminifera, algae, bivalve, brachiopods fragments, corals and bryozoans, etc. In the Bamian zone the unconformity between Upper Carboniferous and Lower Permian;indicates extensive gap in sedimentation, traceable to many parts of Afghanistan as unconformity or tectonic contact is considered here as sequence boundary.

Sedimentary Features and Paleogeographic Evolution of the Middle Permian Trough Basin in Zunyi,Guizhou,South China

Based on detailed field surveys,numerous sections and drillcores as well as analyses of lithofacies and sedimentary facies,sedimentary differentiation in the Middle Permian Zunyi(northern Guizhou,South China)trough basin was studied in detail.Caused by activities of the Emeishan mantle plume,the regional extensional setting and the extinguishing of carbonate production factories were shown from Guizhou to Yunnan.Three types of sedimentary enironments were developed in the study area:platform,slope,and basin.In this work,we established a sedimentary model for the study area,identified 14 syndepositional faults,and created the detailed reconstruction of the trough basin via a sedimentological investigation.It is found that the paleogeographic evolution of the study area can be divided into six stages:(1)a pre-rifting stage,(2)rapid rifting and subsidence,(3)stable rifting and subsidence,(4)the second stage of rifting and subsidence,(5)silicification,and(6)regional uplift and denudation.The sedimentary features and paleogeographic evolution of the Maokou Formation in Zunyi show that the platform,slope,and basin sedimentary features coexisted.In addition,the extensional setting and extinguishing of carbonate production factories were important preconditions for the evolution of the platform region in the study area,and the activity of syndepositional faults also played an important role in the paleogeographic evolution of this area.

Tectonic implications of Late Paleozoic stratigraphic distribution in Northeast China and adjacent region

An analysis of the distribution of the Late Paleozoic strata on Northeast China and adjacent region reveals a zonal pattern of the distribution around the core of the Jiamusi-Mongolia Block.The main part of Late Paleozoic marine strata in this area is considered the continental margin deposits of the Jia-musi-Mongolia Block by analyzing the stratigraphic contact relationship,lithofacies,etc.The results are exhibited in a series of tectonic paleogeographic maps.This presents an important proof for the foundation of the Jiamusi-Mongolia Block,and confines the forming time of Jiamusi-Mongolia Block to the Late Silurian.

The Early Paleozoic paleogeography of the North China block and the other major blocks of China

With the summarization of the Early Paleozoic paleomagnetic data recently obtained from the three major blocks of China, the Early Paleozoic (i.e. Cambrian and Ordovician) paleogeographic positions of the North China, South China and Tarim blocks were discussed in detail. The North China, South China and Tarim blocks were inferred to be located adjacent to East Gondwana in low latitudes of the Southern Hemisphere during the Early Cambrian. During the Early-Middle Ordovician, the South China and Tarim blocks were also located in low latitudes of the Southern Hemisphere with some affinities of the Gondwanaland, whereas the North China block may have episodically separated from the Gondwanaland, and might be sited close to the North America and Siberia. The reestablished paleogeographic configurations are in agreement with the studies on the biogeography, paleoclimate and sedimental facies of the North China and South China blocks.