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Middle Jurassic (middle + jurassic)
Selected AbstractsAN ASSESSMENT OF VARIABILITY IN THEROPOD DINOSAUR REMAINS FROM THE BATHONIAN (MIDDLE JURASSIC) OF STONESFIELD AND NEW PARK QUARRY, UK AND TAXONOMIC IMPLICATIONS FOR MEGALOSAURUS BUCKLANDII AND ILIOSUCHUS INCOGNITUSPALAEONTOLOGY, Issue 4 2009ROGER B. J. BENSON Abstract:, The assemblage of large-bodied theropod remains from the Taynton Limestone Formation (middle Bathonian) of Stonesfield, Oxfordshire and the Chipping Norton Limestone Formation (lowest Bathonian) of New Park Quarry, Gloucestershire, UK is interpreted as monospecific. An assessment of morphological variation in theropod fossils from these localities reveals no taxonomically-significant variation among remains representing large-bodied individuals. Previous observations of anatomical variation among femora, ilia and scapulocoracoids are attributed to postmortem damage and deformation. Referral of all such material to the first named dinosaur taxon, Megalosaurus bucklandii Mantell, is therefore justified. ,Iliosuchus incognitus' lacks autapomorphies and is a nomen dubium. However, other remains of small-bodied theropods from Stonesfield indicate a minimum of two small-bodied taxa that are distinct from M. bucklandii. [source] The rock-hewn churches of Tigrai, Northern Ethiopia: A geological perspectiveGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 7 2002Asfawossen Asrat Ethiopia is endowed with many rock-hewn churches, with the largest group in central and eastern Tigrai. These churches can be divided into four zones: the Atsbi, Hawzen-Ger'alta, Sinkata-Adigrat, and Tembien, with more than 100 rock-hewn churches of different ages, sizes, and histories. However, they have one thing in common: All are carved into sandstone. The Enticho, Adigrat, and Ambaradam sandstones (Permo-Carboniferous, Triassic,Middle Jurassic, and Early Cretaceous, respectively) are extensively exposed in these areas and are characterized by thick and massive beds of coarse- to fine-grained and well-sorted successions. These sandstones are easily carved, yet compact enough to withstand pressure. Although limestone, basalt, and crystalline rocks are exposed in the same area, few rock-hewn churches have been carved into them. The rock type is, therefore, the most important factor in the location of these rock-hewn churches. © 2002 Wiley Periodicals, Inc. [source] Palaeomagnetism, rock magnetism and geochemistry of Jurassic dykes and correlative redbeds, Massachusetts, USAGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 1 2000Suzanne A. McEnroe Jurassic diabase dykes, sills and sedimentary rocks in central Massachusetts were sampled for palaeomagnetic analysis. The intrusions fall into three of the chemical types for eastern North American diabases: high TiO2 quartz-normative (Holden); low TiO2 quartz-normative (Ware); and high Fe2O3 quartz-normative (Pelham,Loudville). The characteristic magnetizations in the majority of intrusive samples unblock between 550 °C and 580 °C, with Curie temperatures in a discrete interval between 556 °C and 580 °C. The dominant remanence in the diabases is carried by C1 to C3 oxidation-exsolved titanomagnetite occurring as euhedral grains, as fine needles or dust in the matrix, as devitrifed glass, and as fine magnetite-ilmenite-silicate symplectite. In some dykes, titanomagnetite was further modified by deuteric oxidation during post-magmatic cooling, creating titanomaghematite and/or a granulation of the magnetite. Palaeopoles for the three diabase groups are: Holden, 60.1°N, 80.5°E, A95 = 4.1°; Ware, 73.5°N, 85.8°E, A95 = 3.9°; and Pelham,Loudville, 65.3°N, 95.6°E, A95 = 4.1°. These data are combined with samples from two stratigraphic sections through the Early Jurassic part of the Sugarloaf Formation in the Deerfield Basin representing both fine-grained mudstones and coarser arkoses. These haematite-dominated rocks reveal several components of magnetization, a steep recent field direction, an intermediate secondary diagenetic overprint direction in both mudstones and arkoses, and a high-temperature shallow primary direction found only in the mudstones. Palaeopoles for the Sugarloaf Formation are: mudstones, 57.7°N, 81.3°E, A95 = 9.1°; and arkoses, 75.1°N, 131.6°E, A95 = 5.9°. Based on the new palaeomagnetic data reported here, the North American plate in the Middle Jurassic was at higher palaeolatitudes than indicated by the present North American apparent polar wander path. [source] Discovery of Jurassic ammonoids from the Shyok suture zone to the northeast of Chang La Pass, Ladakh, northwest India and its tectonic significanceISLAND ARC, Issue 1 2007Masayuki Ehiro Abstract Callovian (late Middle Jurassic) ammonoids Macrocephalites and Jeanneticeras were recovered from the Shyok suture zone, northeast of Chang La Pass, Ladakh, northwest India. They are the first reliable Jurassic fossils and the oldest chronologic data from the Shyok suture zone. The ammonoid-bearing Jurassic strata, newly defined as the Tsoltak Formation, consist largely of terrigenous mudstone with thin sandstone beds and were probably a part of the continental basement to the Cretaceous Ladakh Arc. [source] Metamorphism and metamorphic K,Ar ages of the Mesozoic accretionary complex in Northland, New ZealandISLAND ARC, Issue 3 2004Yujiro Nishimura Abstract A southwest dipping Mesozoic accretionary complex, which consists of tectonically imbricated turbiditic mudstone and sandstone, hemipelagic siliceous mudstone, and bedded cherts and basaltic rocks of pelagic origin, is exposed in northern North Island, New Zealand. Interpillow limestone is sometimes contained in the basaltic rocks. The grade of subduction-related metamorphism increases from northeast to southwest, indicating an inverted metamorphic gradient dip. Three metamorphic facies are recognized largely on the basis of mineral parageneses in sedimentary and basaltic rocks: zeolite, prehnite-pumpellyite and pumpellyite-actinolite. From the apparent interplanar spacing d002 data for carbonaceous material, which range from 3.642 to 3.564 Å, the highest grade of metamorphism is considered to have attained only the lowermost grade of the pumpellyite-actinolite facies for which the highest temperature may be approximately 300°C. Metamorphic white mica K,Ar ages are reported for magnetic separates and <2 µm hydraulic elutriation separates from 27 pelitic and semipelitic samples. The age data obtained from elutriation separates are approximately 8 m.y. younger, on average, than those from magnetic separates. The age difference is attributed to the possible admixture of nonequilibrated detrital white mica in the magnetic separates, and the age of the elutriation separates is considered to be the age of metamorphism. If the concept, based on fossil evidence, of the subdivision of the Northland accretionary complex into north and south units is accepted, then the peak age of metamorphism in the north unit is likely to be 180,130 Ma; that is, earliest Middle Jurassic to early Early Cretaceous, whereas that in the south unit is 150,130 Ma; that is, late Late Jurassic to early Early Cretaceous. The age cluster for the north unit correlates with that of the Chrystalls Beach,Taieri Mouth section (uncertain terrane), while the age cluster for the south unit is older than that of the Younger Torlesse Subterrane in the Wellington area, and may be comparable with that of the Nelson and Marlborough areas (Caples and Waipapa terranes). [source] Jurassic depositional records and sandstone provenances in Hefei Basin, central China: Implication for Dabie orogenesisISLAND ARC, Issue 2 2004Zhong Li Abstract Detrital composition and major element geochemistry of Jurassic sandstones in the south Hefei Basin, central China, show their provenance to be the Dabie Mountains, whose tectonic attributes are closely related to continent,island arc complexes. It was found that a provenance change, from recycled orogen signatures and mixed orogenic sandstones to arc orogen, occurs from the lower Middle Jurassic to the Upper Jurassic (the Zhougongshan Formation). Dissected magmatic arc sources were gradually exposed in the Dabie Mountains due to intensive exhumation during the Late Jurassic, particularly after the Fenghuangtai depositional phase. Furthermore, it can be infered that the magmatic arc was initially present in both the Early Paleozoic and the Triassic, according to isotopic dating studies in previously published reports. ,13C,,18O tracing between existing marbles of different strata in the Dabie block and marble gravels of the Fenghuangtai Formation in the Hefei Basin indicate that partial lithostratigraphic units for the Jurassic provenances have entirely disappeared from the Dabie block; therefore, it is impossible to reconstruct integral orogenic processes from studies on the remaining Dabie block alone. These findings, together with basin-fill sequences, also suggest that the Hefei Basin was mainly subjected to compressive mechanical regimes rather than extensional regimes in the Jurassic, which resulted in reverse-grading clastic depositional sequences, and is probably related to the northward intracontinental deep subduction of the Yangtze Plate. Regional exhumation properties and a tectonic model of the Late Mesozoic Dabie orogenesis are discussed in this paper. [source] Transformation of the pectoral girdle in the evolutionary origin of frogs: insights from the primitive anuran DiscoglossusJOURNAL OF ANATOMY, Issue 1 2006Pavla Havelková Abstract Using cleared-and-stained whole mounts and computer-aided three-dimensional reconstructions made from serial histological sections, we studied the development of the pectoral girdle in Discoglossus pictus, an extant member of an ancient frog lineage, represented for example by Eodiscoglossus from the Middle Jurassic to Early Cretaceous periods in Europe. Basic developmental features were compared with those of extinct Temnospondyli, considered to be the most probable anuran ancestors, and with Triadobatrachus, an early Triassic proanuran. In the endochondral girdle, the separate scapula and coracoid of Discoglossus and other anurans (completed by suprascapular and procoracoid cartilages) evolved from the compact scapulocoracoid of temnospondyls by paedomorphosis. In parallel, the dermal ossifications of the girdle were reduced to a small clavicle and cleithrum. The overall reduction in ossification of the anuran pectoral girdle supports the hypothesis of a paedomorphic origin for Anura. The almost simultaneous appearance of dermal and endochondral ossifications may be explained by the accumulation of developmental events during a short, distinct metamorphosis (which did not occur in neotenic temnospondyls living permanently in water). The sternal elements seem to be neomorphs for the most part, which help to cushion the shock of landing in jumping anurans but which also evolved as functional substitutes (insertion area for the pectoralis muscles) of the temnospondyl interclavicle. [source] UPPER TRIASSIC-MIDDLE JURASSIC STRATIGRAPHY AND SEDIMENTOLOGY IN THE NE QAIDAM BASIN, NW CHINA: PETROLEUM GEOLOGICAL SIGNIFICANCE OF NEW OUTCROP AND SUBSURFACE DATAJOURNAL OF PETROLEUM GEOLOGY, Issue 4 2003Yang Yongtai Although Mesozoic source and reservoir rocks are known to occur at oilfields in the northern Qaidam Basin (NW China), the precise identification and distribution of Mesozoic rocks in the subsurface are outstanding problems. The Dameigou locality has in the past been considered as the type section for Lower-Middle Jurassic strata in northern Qaidam. Previous studies have concluded that the onset of non-marine sedimentation here took place in the Early Jurassic; and that Mesozoic strata penetrated by wells in the Lenghu structural zone are Middle Jurassic. In this paper, we present new data from the Lengke-1 well, drilled in the Lenghu structural zone in 1997. This data indicates the existence of a more extensive pre-Middle Jurassic stratigraphy than has previously been recognized. Biostratigraphic data together with regional seismic mapping suggest that the pre-Middle Jurassic succession at Lengke-1 includes both Late Triassic and Early Jurassic deposits. The Late Triassic sedimentary rocks appear to have been deposited in local half graben, some of which were later inverted during Jurassic, Cretaceous and Cenozoic tectonism. Lower and Middle Jurassic strata (lacustrine and fluvial deposits) are present in the SW and NE parts of the Lenghu structural zone, respectively. Extensive organic-rich intervals are present in both successions. Lower Jurassic lacustrine mudstones may represent a previously under-appreciated, and potentially large, source rock sequence. [source] Dinoflagellate cyst biostratigraphy of the Opalinuston Formation (Middle Jurassic) in the Aalenian type area in southwest Germany and north SwitzerlandLETHAIA, Issue 1 2010SUSANNE FEIST-BURKHARDT Feist-Burkhardt, S. & Pross, J. 2010: Dinoflagellate cyst biostratigraphy of the Opalinuston Formation (Middle Jurassic) in the Aalenian type area in southwest Germany and north Switzerland. Lethaia, Vol. 43, pp. 10,31. In order to provide a detailed dinoflagellate cyst stratigraphy of the Lower Aalenian Opalinuston Formation from the Aalenian type area, 68 samples from four boreholes and one outcrop section were analysed. The sample localities are Hausen an der Fils and Wittnau in southwest Germany, Weiach in north Switzerland and Mont Russelin in the Swiss Jura Mountains. Dinoflagellate cyst assemblages were recovered from the Late Toarcian Aalensis Zone to the Late Aalenian Murchisonae Zone. The samples yielded rich, well-preserved and diverse assemblages with 51 dinoflagellate cyst taxa identified in total. The dinoflagellate cyst distribution data obtained from this study allow a high-resolution biostratigraphical subdivision of the lowermost Middle Jurassic Opalinuston Formation into four palynostratigraphical units. First and last occurrences, acmes and consistent presence of the species Batiacasphaera sp. A, Evansia cf. granochagrinata, Kallosphaeridium praussii, Nannoceratopsis triangulata, Phallocysta? frommernensis and Wallodinium laganum were selected as the criteria for defining these units. The obtained high-resolution palynostratigraphical scheme provides a basis for establishing and further refining early Middle Jurassic biostratigraphy in the Boreal and Tethyan realms. ,Aalenian, biostratigraphy, dinoflagellate cysts, Germany, Jurassic, Switzerland, Toarcian. [source] First evidence of stegosaurian Deltapodus footprints in North Africa (Iouaridène Formation, Upper Jurassic, Morocco)PALAEONTOLOGY, Issue 1 2010MATTEO BELVEDERE Abstract:, New findings of dinosaur footprints are described from the Upper Jurassic Iouaridène ichnosite of Morocco. On the top of two surfaces, stratigraphically close to that bearing the famous Breviparopus taghbaloutensis trackways, two footprints were excavated and assigned to the ichnogenus Deltapodus. This ichnogenus is well known from the Middle Jurassic of Yorkshire and also occurs in Upper Jurassic deposits from Iberia and the United States. This finding represents the first record of Deltapodus from Africa. These footprints, probably produced by stegosaurian dinosaurs, add new data on the distribution of this type of dinosaur and on the connection between the northern and southern margin of Tethys. 3D models have been generated to allow more detailed studies and to record these unique footprints. [source] A NEW MIDDLE JURASSIC APHID FAMILY (INSECTA: HEMIPTERA: STERNORRHYNCHA: SINOJURAPHIDIDAE FAM.PALAEONTOLOGY, Issue 3 2008CHINA, NOV.) FROM INNER MONGOLIA Abstract:, A new monotypic aphid family, Sinojuraphididae, is described from the Middle Jurassic of China. Its antennae and wing venation have very plesiomorphic structures, even more than in known Triassic taxa (e.g. 12 antennomeres, Cu with a very long stem, very narrow pterostigma), confirming the persistence of ancient, probably Triassic, lineages among Jurassic aphids. [source] The black layer in cephalopods from the German Muschelkalk (Triassic)PALAEONTOLOGY, Issue 6 2004Christian Klug Thin, dark, probably phosphatic coatings were found on the dorsum in front of and sometimes behind the aperture of 50 specimens of Paraceratites and Ceratites (Ammonoidea) belonging to 14 species and subspecies and in three specimens of Germanonautilus, all from the Middle Triassic of Germany. The proportions, occurrences, position, outline, and preservation in fossil Nautiloidea and Ammonoidea (originally organic matter) of this structure support the hypothesis that it is homologous with the black layer in Recent Nautilus and Allonautilus. It is not yet possible to test whether these cephalopods show homologous styles of the development of these structures or whether the black layer can be identified in a common ancestor. In contrast to many ammonoids, Ceratites and Paraceratites, most Palaeozoic ammonoids, and some Mesozoic ammonoids probably did not have lower mandibles that were suitable for the closure of the aperture. They probably possessed a dorsally extending mantle (supracephalic mantle fold) and a hood, as in Recent Nautilus and Allonautilus, that was attached to the black layer. This interpretation is corroborated by a similar morphology of the black layer in an adult specimen of the nautilid Cenoceras from the South German Middle Jurassic and three specimens of Germanonautilus from the South German Middle Triassic (both Nautiloidea). [source] The Rutland Cetiosaurus: the anatomy and relationships of a Middle Jurassic British sauropod dinosaurPALAEONTOLOGY, Issue 6 2002Paul Upchurch A relatively well,preserved specimen of Cetiosaurus oxoniensis, from the Middle Jurassic (Bajocian) of Rutland, United Kingdom, is described in detail. The material includes a nearly complete cervical series, representative dorsal vertebrae, a fragment of sacrum, anterior caudals, the right femur, and numerous rib and limb fragments. Contrary to previous suggestions that this specimen possesses 14 cervical and ten dorsal vertebrae, it seems more probable that there were at most 13 cervicals and at least 12 dorsals. The vertebral column displays several autapomorphic features which supplement the generic diagnosis of Cetiosaurus, including: (1) a stout, anteriorly directed process located at the top of the neural spine of the twelfth (?) cervical vertebra; and (2) the presence of lateral pits, separated by a thin midline septum, below the transverse processes of middle dorsal vertebrae. Cladistic analysis indicates that Cetiosaurus is probably the sister,taxon to the advanced neosauropod clade. This relationship affects the distribution of particular character states that have played an important role in determining sauropod phylogeny. [source] Poekilopleuron bucklandii, the theropod dinosaur from the Middle Jurassic (Bathonian) of NormandyPALAEONTOLOGY, Issue 6 2002Ronan Allain Poekilopleuron bucklandii, described by Eudes,Deslongchamps in 1838, is one of the earliest discovered dinosaurs. Although incomplete, it is one of the best preserved Middle Jurassic theropods known from Europe. Unfortunately, the only specimen of P. bucklandii, housed in the Musée de la Faculté des Sciences de Caen, was destroyed during World War II. However, casts of some parts of the type skeleton have been found in the collections of the Museum National d'Histoire Naturelle, Paris. These casts and Eudes,Deslongchamps' monograph are used to redescribe the specimen. Poekilopleuron shares one synapomorphy with the Spinosauroidea and we tentatively assign it to that clade. The possible synonymy between Poekilopleuron and Megalosaurus is examined and we conclude that Megalosaurus is a nomen dubium and that the name should be restricted to the type dentary. [source] Geology, Wall-rock Alteration and Vein Paragenesis of the Bilimoia Gold Deposit, Kainantu Metallogenic Region, Papua New GuineaRESOURCE GEOLOGY, Issue 3 2007Joseph Onglo Espi Abstract The Bilimoia deposit (2.23 Mt, 24 g/t Au), located in the eastern Central Mobile Belt of mainland Papua New Guinea, is composed of fault-hosted, NW,NNW-trending Irumafimpa,Kora and Judd,Upper Kora Au-quartz veins hosted by Middle,Late Triassic basement that was metamorphosed to medium-grade greenschist facies between Middle,Late Triassic and Early,Middle Jurassic. Mineralizing fluids were introduced during crustal thickening, rapid uplift, change of plate motions from oblique to orthogonal compression, active faulting and S3 and S4 events in an S1,S4 deformation sequence. The Bilimoia deposit is spatially and temporally related to I-type, early intermediate to felsic and late mafic intrusions emplaced in Late Miocene (9,7 Ma). Hydrothermal alteration and associated mineralization is divided into 10 main paragenetic stages: (1) chlorite,epidote-selvaged quartz,calcite,specularite vein; (2) local quartz,illite,pyrite alteration; (3) quartz,sericite,mariposite,fuchsite,pyrite wall-rock alteration that delimits the bounding shears; (4) finely banded, colloform-, crustiform- and cockade-textured and drusy quartz ± early wolframite ± late adularia; (5) hematite; (6) pyrite; (7) quartz ± amethyst-base metal sulfides; (8) quartz,chalcopyrite,bornite,Sn and Cu sulfides,Au tellurides and Te ± Bi ± Ag ± Cu ± Pb phases; (9) Fe ± Mn carbonates; and (10) supergene overprint. Fluid inclusions in stage 4 are characterized by low salinity (0.9,5.4 wt% NaCl equivalent), aqueous,carbonic fluids with total homogenization temperatures ranging from 210 to 330°C. Some of the inclusions that homogenized between 285 and 330°C host coexisting liquid- and vapor-rich (including carbonic) phases, suggesting phase separation. Fluid inclusions in quartz intergrown with wolframite have low salinity (0.9,1.2 wt% NaCl equivalent), aqueous,carbonic fluids at 240,260°C, defining the latter's depositional conditions. The ore fluids were derived from oxidized magmatic source initially contaminated by reduced basement rocks. Wall-rock alteration and involvement of circulating meteoric waters were dominant during the first three stages and early part of stage 4. Stage 5 hematite was deposited as a result of stage 4 phase separation or entrainment of oxygenated groundwater. Gold is associated with Te- and Bi-bearing minerals and mostly precipitated as gold-tellurides during stage 8. Gold deposition occurred below 350°C due to a change in the sulfidation and oxidation state of the fluids, depressurization and decreasing temperature and activities of sulfur and tellurium. Bisulfides are considered to be the main Au-transporting complexes. The Bilimoia deposit has affinities that are similar to many gold systems termed epizonal orogenic and intrusion-related. The current data allow us to classify the Bilimoia deposit as a fault-controlled, metamorphic-hosted, intrusion-related mesothermal to low sulfidation epithermal quartz,Au,Te,Bi vein system. [source] Rare Earth, Major and Trace Elements in the Kunimiyama Ferromanganese Deposit in the Northern Chichibu Belt, Central Shikoku, JapanRESOURCE GEOLOGY, Issue 4 2005Yasuhiro Kato Abstract. Rare earth, major and trace element geochemistry is reported for the Kunimiyama stratiform ferromanganese deposit in the Northern Chichibu Belt, central Shikoku, Japan. The deposit immediately overlies greenstones of mid-ocean ridge basalt (MORB) origin and underlies red chert. The ferromanganese ores exhibit remarkable enrichments in Fe, Mn, P, V, Co, Ni, Zn, Y and rare earth elements (excepting Ce) relative to continental crustal abundance. These enriched elements/ Fe ratios and Post-Archean Average Australian Shale-normalized REE patterns of the ferromanganese ores are generally analogous to those of modern hydrothermal ferromanganese plume fall-out precipitates deposited on MOR flanks. However in more detail, Mn and Ti enrichments in the ferromanganese ores are more striking than the modern counterpart, suggesting a significant contribution of hydrogenetic component in the Kunimiyama ores. Our results are consistent with the interpretation that the Kunimiyama ores were umber deposits that primarily formed by hydrothermal plume fall-out precipitation in the Panthalassa Ocean during the Early Permian and then accreted onto the proto-Japanese island arc during the Middle Jurassic. The presence of strong negative Ce anomaly in the Kunimiyama ores may indicate that the Early Permian Panthalassa seawater had a more striking negative Ce anomaly due to a more oxidizing oceanic condition than today. [source] Detrital zircon geochronology and its provenance implications: responses to Jurassic through Neogene basin-range interactions along northern margin of the Tarim Basin, Northwest ChinaBASIN RESEARCH, Issue 1 2010Zhong Li ABSTRACT Previously published research from the Kuqa Subbasin along northern margin of the Tarim Basin shows five tectonic-depositional phases from Triassic to Neogene time. In order to reveal additional detailed information on the nature of provenance terrains and tectonic attributes since late Mesozoic time, five typical sandstone samples from Jurassic,Neogene strata were collected for U,Pb dating of detrital zircons. Geochronological constitution of detrital zircons of the Middle Jurassic sample is essentially unimodal and indicates major contributions from the South Tian Shan even Yili,Central Tian Shan, wherein most 370,450 Ma zircons probably resulted from tectonic accretion events between the Yili,Central Tian Shan block and South Tian Shan Ocean during Silurian and Devonian time, with sandstone provenance tectonic attributes of passive continental margin. The Lower Cretaceous sample shows a complicated provenance detrital zircon signature, with new peak ages of 290,330 Ma as well as 370(or 350),450 Ma showing evident arc orogenic provenance tectonic attribute, probably reflecting a new provenance supply that resulted from denudation process whthin the South Tian Shan and South Tian Shan suture. There are no obvious changes within age probability spectra of detrital zircons between the Cretaceous and early Paleogene samples, which suggests that similar provenance types and basin-range framework continued from Cretaceous to Early Paleogene time. However, unlike the Cretaceous and early Paleogene samples, an age spectra of the Miocene sample is relatively unimodal and similar to that of the Pliocene sample, with peak ages ranging between ,392 and ,458 Ma older than the comparable provenance ages (peak ages about 370,450 Ma) of the Middle Jurassic and Lower Cretaceous samples. Therefore, we conclude that the South Tian Shan was rapidly exhumated and the southern South Tian Shan had become the main source of clastics for the Kuqa Subbasin since the Miocene epoch. [source] Synsedimentary tensional features in Upper Triassic shallow-water platform carbonates of the Carnian Prealps (northern Italy) and their importance as palaeostress indicatorsBASIN RESEARCH, Issue 2 2000Cozzi The extensive shallow-water carbonate platform deposits of the Dolomia Principale Formation (Southern Alps, northern Italy) accumulated during the Late Triassic, a time of plate-scale reorganization and rifting. Synsedimentary tensional features such as fractures, neptunian dykes, normal faults, shatter breccias and laterally discordant intraformational breccias have been studied within a well-preserved platform-to-basin transition in the Monte Pramaggiore area (Carnian Prealps). These tensional features follow three preferential orientations: N,S, E,W and NE,SW. To fully explain these different arrays it is proposed that the study area experienced during the Late Triassic the waning rifting phase connected to the westward propagation of the NeoTethys (N,S extension) and the onset of the rifting phase that led in the Middle Jurassic to the opening of the Central Atlantic (E,W extension), with a contemporaneous reactivation of Early,Middle Triassic NE,SW-orientated faults. This palaeostress analysis reveals the good potential of tensional features as reliable palaeostress indicators. [source] A New Species of the Family Juraperlidae (Insecta: Grylloblattida) from the Middle Jurassic of ChinaACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 4 2010CUI Yingying Abstract: Juraperla grandis sp. nov. (Grylloblattida: Juraperlidae) is described from the Daohugou locality (Middle Jurassic, China). Its wing venation is very similar to that of Juraperla daohugouensis Huang and Nel, 2007 (Grylloblattida: Juraperlidae), in the particular occurrence of a supplementary longitudinal vein in the area between the anterior wing margin and ScP. The larger size of the new specimen, the lower number of CuAl branches, and the occurrence of two rows of cells between MP and CuA in forewings justify the erection of a new species, J. grandis sp. nov.. The material also preserved hind wing and body structures, described for the first time in Juraperlidae. [source] Current Knowledge of Mesozoic Coleoptera from Daohugou and Liaoning (Northeast China)ACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 4 2010Alexander G. KIREJTSHUK Abstract: The present paper is devoted to an overview on fossil Coleoptera studied from Inner Mongolia, Daohugou (Middle Jurassic, Jiulongshan Formation) and Liaoning (Upper Jurassic-Lower Cretaceous, Yixian Formation) deposited in Chinese collections. As a result, species of the tribe Sperchopsini and Hydrophilini from Hydrophilidae, families and subfamilies Silphidae, Syndesinae from Lucanidae, Pleocomidae, Trogidae, Trogissitidae, Pyrochroidae, Diaperinae from Tenebrionidae, and Cerambycidae were first registered in the Mesozoic and some families were defined as new. It was shown that many superfamilies represented in the Recent Fauna were formed within the Middle Jurassic and Lower Cretaceous. The materials examined confirm the hypothesis that Cucujiformian beetles are a younger group than other infraordera of Polyphaga (Staphyliniformia and Elateriformia) and, therefore, they appeared in the fossil record only in the late Mesozoic. It was shown and confirmed that most superfamilies appeared in the fossil records before Cucujoidea. The synonymy of Notocupes Ponomarenko, 1964; Sinocupes Lin, 1976, syn. nov.; Amblomma Tan, Ren et Liu 2005, syn. nov.; Euryomma Tan, Ren et Shih, 2006, syn. nov., non Stein, 1899 and Ovatocupes Tan et Ren, 2006, syn. nov.; synonymy of Tetraphalerus Waterhouse, 1901 and Odontomma Tan, Ren et Ge 2006, syn. nov.; and synonymy of Priacmopsis Ponomarenko, 1966 and Latocupes Tan et Ren, 2006, syn. nov. are proposed. Sinorhombocoleus papposus Tan et Ren, 2009 is transferred from the family Rhombocoleidae to Schizophoridae. Cervicatinius complanus Tan, Ren et Shih, 2007 and Forticatinius elegans Tan, Ren et Shih, 2007 are transferred from the family Catiniidae (suborder Archostemata) to superfamily Cleroidea (suborder Polyphaga: first among the family Peltidae and second as a closely related group to the latter family). The family Parandrexidae is transferred from the superfamily Cucujoidea to Cleroidea. The ecological circumstances of the past ecosystems and hypotheses of historical development of the order Coleoptera are discussed. The age of faunas examined is considered. The list of the taxa described from Daohugou and Liaoning is compiled. [source] Early Evolution of Apocrita (Insecta, Hymenoptera) as Indicated by New Findings in the Middle Jurassic of Daohugou, Northeast ChinaACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 4 2010Alexandr P. RASNTTSYN Abstract: The classification and phylogeny of the basal Vespina (= Orussoidea + Apocrita) are reconsidered based primarily on rich and well preserved material from the Middle Jurassic of Daohugou in Inner Mongolia, China. Comparatively smooth morphological transitions are traced from a Xiphydriidae-like ancestor toward Orussoidea via the Jurassic family Karatavitidae, and through Karatavitidae and the Jurassic and Early Cretaceous family Ephialtitidae independently to Stephanidae, to Evanioidea, and, via the extinct Jurassic Kuafuidae fam. nov. to the remaining Apocrita. New hypothesis is proposed concerning development of the characteristic wasp-waist of Apocrita, which is supposed to appear independently and in different ways in Evanioidea and in the rest of Apocrita. As a result, six infraorders are proposed for the suborder Vespina with the following taxonomic structure: infraorder Orussomorpha including the only superfamily Orussoidea (Karatavitidae + Paroryssidae + Orussidae), infraorder Stephanomorpha with the only superfamily Stephanoidea (Ephialtitidae + Stephanidae), infraorder Evaniomorpha with the only superfamily Evanioidea of traditional composition, infraorder Ceraphronomorpha with the superfamilies Ceraphronoidea s. str. and monotypical Megalyroidea and Trigonaloidea, and the infraorders Proctotrupomorpha, Ichneumonomorpha, and Vespomorpha of traditional composition. The family Kuafuidae is unplaced to infraorder because it is putatively paraphyletic with respect to Ceraphronomorpha, Proctotrupomorpha, Ichneumonomorpha and Vespomorpha. Described as new are Karatavites junfengi sp. nov., Praeratavites wuhuaensis sp. nov., P. perspicuus sp. nov., Postxiphydria daohugouensis gen. et sp. nov., P. ningchengensis gen. et sp. nov., Postxiphydroides strenuus gen. et sp. nov., Praeratavitoides amabilis gen. et sp. nov., Proapocritus densipediculus sp. nov., P. sculptus sp. nov., P. longantennatus sp. nov., P. formosus sp. nov., P. atropus sp. nov., P. elegans sp. nov., Stephanogaster pristinus sp. nov., Asiephialtites lini sp. nov., Praeproapocritus vulgatus gen. et sp. nov., Sinaulacogastrinus solidus gen. et sp. nov., Sinevania speciosa gen. et sp. nov., Eonevania robusta gen. et sp. nov., Kuafua polyneura gen. et sp. nov. (all from the Middle Jurassic of Daohugou), as well as Kuafuidae fam. nov. including Kuafua gen. nov. as well as Arthrogaster Rasnitsyn, 1975, and Leptogastrella Rasnitsyn, 1975 from the Upper Jurassic of Karatau in Kazakhstan. [source] A New Family of Moths from the Middle Jurassic (Insecta: Lepidoptera)ACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 4 2010HUANG Diying Abstract: Three lepidopteran species, from the Middle Jurassic Daohugou beds (inner Mongolia, China), are described in a new family, Mesokristenseniidae, and new genus, Mesokristensenia, which could represent the sister group of the Micropterigidae. Mesokristensenia differs from all extant Lepidoptera, but one genus (Agathiphaga, Agathiphagidae), in retaining four median veins in the forewing, a plesiomorphy also present in many Trichoptera. Evidence for placing Mesokristensenia in the Lepidoptera includes four traits, notably a previously unrecorded autapomorphy of this insect order: beyond stem M1+2, vein M1 is bent and connected to cross-vein r-m (in both wing pairs). Among 24 characters taken into account to assess the systematic position of Mesokristensenia, 12 are considered informative for a cladistic analysis involving this fossil taxon and the four suborders recognized in present-day Lepidoptera (Zeugloptera, Aglossata, Heterobathmiina, and Glossata). [source] New Jurassic Pseudopolycentropodids from China (Insecta: Mecoptera)ACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 1 2010Dong REN Abstract: In this paper two new species of fossil Pseudopolycentropus Handlirsch, 1906 are described: Pseudopolycentropus janeannae sp. nov. and P. novokshonovi, sp. nov. All of them were recovered from the Middle Jurassic non-marine sedimentary strata of northeastern China. The new material from China reveals that the early diversification of pseudopolycentropodids was well underway by the Middle Jurassic. [source] Paleogeographical Distribution of Mesozoic Palaeontinidae (Insecta, Hemiptera) in China with Description of New TaxaACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 1 2010Bo WANG Abstract: 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 Lagerstätte. 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. [source] Xingxueanthus: An Enigmatic Jurassic Seed Plant and Its Implications for the Origin of AngiospermyACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 1 2010Xin WANG Abstract: The origin of angiosperms has been tantalizing botanists for centuries. Despite the efforts of palaeobotanists, most of the pre-Cretaceous angiosperms are regarded either non-convincing or misdated. The applications of SEM and LM (light microscope) enable us to recognize a coalified fossil plant, Xingxueanthus sinensis gen. et sp. nov., from the Haifanggou Formation (Middle Jurassic, >160 Ma) in western Liaoning, China. Xingxueanthus is an "inflorescence" with more than 20 female units spirally arranged. Each female unit is situated in the axil of a bract. The female unit is composed of an ovule-container and a style-like projection at the top. There is a vertical column bearing several ovules in the ovule-container. The general morphology and the internal structure of Xingxueanthus distinguish itself from any known fossil and extant gymnosperms, and its structures are more comparable to those of angiosperms. Xingxueanthus, if taken as a gymnosperm, would represent a new class, demonstrate an evolutionarily advanced status of ovule-protection in gymnosperms never seen before, and provide new insights into the origin of angiospermy. Alternatively, if taken as an angiosperm, together with Schmeissneria, it would increase the diversity of Jurassic angiosperms, which has been underestimated for a long time, and suggest a much earlier origin of angiospermy than currently accepted. [source] A New Non-Pterodactyloid Pterosaur from Qinglong County, Hebei Province of ChinaACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 2 2009Junchang LÜ Abstract: A new basal non-pterodactyloid pterosaur, Changchengopterus pani gen. et sp. nov., is erected, on the basis of a nearly complete postcranial skeleton. The new taxon is distinguished by relatively short extensions of the prezygapophyses, postzygapophyses and haemal arches of the caudal vertebrae; a humerus that has a subtriangular deltopectoral crest; limb elements that decrease in length in the following order: ulna> wing-phalange 2 > wing-phalange 3 = wing-phalange 1>humerus >tibia>femur>wing-metacarpal. Phylogenetic analysis suggests that Changchengopterus is a basal member of rhamphorhynchoids, and more closely related to Dorygnathus than to other rhamphorhychoids. The geological age of the Changchengopterus -bearing sediments is no latter than the end of the Late Jurassic and it is possible Middle Jurassic. [source] New Fossils of Eoptychopteridae (Diptera) from the Middle Jurassic of Northeastern ChinaACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 2 2009Jianying HAO Abstract: Three new species of the extinct genus of Eoptychopterina from the Eoptychopteridae family, Eoptychopterina antica sp. nov., Eoptychopterina adnexa sp. nov., and Eoptychopterina mediata sp. nov., are described and illustrated. These three new species are established based on fossil specimens with bodies and complete wings. All were collected from the Middle Jurassic Jiulongshan Formation of Daohugou in eastern Inner Mongolia, China. Based on the new materials, the name of two species in Eoptychopterina from China,Eoptychopterina elenae Ren and Krzeminski and Eoptychopterina gigantea Zhang,is sysnonymum Junius. [source] Migration of Depocenters and Accumulation Centers and its Indication of Subsidence Centers in the Mesozoic Ordos BasinACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 2 2009Junfeng ZHAO Abstract: Based on the integrated study of structure attributions and characteristics of the original basin in combination with lithology and lithofacies, sedimentary provenance analysis and thickness distribution of the Mesozoic Ordos Basin, it is demonstrated that the depocenters migrated counterclockwise from southeast to the north and then to the southwest from the Middle-Late Triassic to the Early Cretaceous. There were no unified and larger-scale accumulation centers except several small isolated accumulation centers before the Early Cretaceous. The reasons why belts of relatively thick strata were well developed in the western basin in several stages are that this area is near the west boundary of the original Ordos Basin, there was abundant sediment supply and the hydrodynamic effect was strong. Therefore, they stand for local accumulation centers. Until the Early Cretaceous, depocenters, accumulation centers and subsidence centers were superposed as an entity in the southwest part of the Ordos Basin. Up to the end of the Middle Jurassic, there still appeared a paleogeographic and paleostructural higher-in-west and lower-in-east framework in the residual basin to the west of the Yellow River. The depocenters of the Ordos Basin from the Middle,Late Triassic to the Middle Jurassic were superposed consistently. The relatively high thermal maturation of Mesozoic and Paleozoic strata in the depocenters and their neighborhood suggest active deep effects in these areas. Generally, superposition of depocenters in several periods and their consistency with high thermal evolution areas reveal the control of subsidence processes. Therefore, depocenters may represent the positions of the subsidence centers. The subsidence centers (or depocenters) are located in the south of the large-scale cratonic Ordos Basin. This is associated with flexural subsidence of the foreland, resulting from the strong convergence and orogenic activity contemporaneous with the Qinling orogeny. [source] A New Theropod Dinosaur from the Middle Jurassic of Lufeng, Yunnan, ChinaACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 1 2009Xiao-chun WU Abstract: A new theropod dinosaur, Shidaisaurus jinae gen. et sp. nov., has been described on the basis of an incomplete skeleton. The specimen was found near the base of the Upper Lufeng Formation (early Middle Jurassic) in Yunnan, China. It is the first theropod dinosaur from the Middle Jurassic of Yunnan. Shidaisaurus jinae is distinguishable from other Jurassic theropods by certain features from the braincase, axis, and pelvic girdle. The absence of any pleurocoels in the axis or in any anterior dorsal vertebrae suggests that the new Lufeng theropod is relatively primitive and more plesiomorphic than most of the Middle to Late Jurassic theropods from China. Most Chinese taxa of Jurassic theropod dinosaurs have not been well described; a further detailed study will be necessary for us to determine their phylogenetic relationships with Shidaisaurus jinae. [source] New Fossil Palaeontinids from the Middle Jurassic of Daohugou, Inner Mongolia, China (Insecta, Hemiptera)ACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 1 2009Ying WANG Abstract: Two new genera and species of fossil Palaeontinidae are described from Daohugou Village, Inner Mongolia, China: Cladocossus undulatus gen. et sp. nov. and Cricocossus paradoxus gen. et sp. nov. Both new genera are described based on well-preserved forewings. This discovery confirms the high diversity of palaeontinids during the Middle Jurassic. Both specimens have interesting modal structures which are new to Palaeontinidae: M five-branched and M3 with two branches. Based on this character, wing structural characteristic is discussed. [source] | |||||||||||||||||||||||||