Abstract:Editor-in-Chief of Acta Geologica Sinica (English Edition), Research Fellow Zhao Xun, dies in Beijing

Abstract:Brief Introduction to Papers on Pterosaurs

Abstract:A new anurognathid pterosaur specimen from the Middle Jurassic Tiaojishan Formation of Qinglong, northern Hebie Province is described. The new specimen is referred to Dendrorhynchoides, based on the general morphology of the skeleton, but it represents a new species, named here as Dendrorhynchoides mutoudengensis sp. nov.. It is characterized by the presence of short, robust and straight teeth, and bearing wing metacarpal approximately 40% of the length of humerus. The new specimen provides further osteological information for anurognathid pterosaurs, especially the presence of a relatively elongate tail.

Abstract:Northeastern China contains widely distributed Jurassic terrestrial strata that have yielded many spectacular mammal and pterosaur fossils, in addition to feathered dinosaur fossils and more recent discoveries from Jianchang, particularly from western Liaoning. However, the fossil-bearing stratigraphic succession, regional correlation, and age estimates of the fossils found in Jianchang County and nearby areas have been contentious. Here, we report on the vertebrate fossil-bearing Jurassic stratigraphy from Linglongta, Jianchang County, western Liaoning, including a SHRIMP U-Pb zircon date unambiguously associated with the fossil horizons. The primary goal was to determine the vertebrate fossil-bearing succession. A further aim was to provide age estimations for the fossil-bearing horizon as well as the earliest appearance of feathered dinosaurs, the eutherian–placental clade, and transitional pterosaurs. Field investigations showed that the vertebrate fossil-bearing stratigraphic succession in Jianchang County mainly consists of basal andesites overlain by rhythmic tuffs and tuffaceous lacustrine sediments, with the upper intermediate or acidic lavas interbedded with laminated more or less tuffaceous lacustrine deposits. This sequence correlates well with the Middle Jurassic Lanqi/Tiaojishan Formation in northeastern China. Detailed and accurate field observations showed that the well-preserved vertebrate fossils were buried in either the middle or the upper fine-grained laminated lacustrine deposits. Previous and current SHRIMP U-Pb zircon dates provide an age estimation of 161–159 Myr for the fossil-bearing horizon and vertebrates. This indicates that the earliest appearance of feathered dinosaurs here was more than 159 Myr ago and unquestionably older than Archaeopteryx from Germany, making these the earliest known feathered dinosaurs in the world. Furthermore, the eutherian–placental clade and the known transitional pterosaurs first emerged no later than 161 Myr. The vertebrate assemblage unearthed recently from Linglongta and neighboring areas in Jianchang County belongs to the Daohugou Biota. In addition to feathered dinosaurs, this biota was characterized by mammals, primitive pterosaurs, insects, and plants and was present in Inner Mongolia, western Liaoning, and northern Hebei in northeastern China during the Middle–Late Jurassic.

Abstract:The pterosaur collection at the Natural History Museum is of great historical importance. Most of the material is figured or cited, and several specimens are types or casts of types. Pterosaurs from UK localities are well represented, but foreign material is also present as original specimens and as high quality casts. The entire collection has been recorded in a database and curatorial improvements have been made, which has improved physical and virtual access to the collection. Although many of the specimens were collected as long ago as the early 1800s, they are still useful today. A full list of Natural History Museum pterosaur specimens is published, for the first time since 1888.

Abstract:Phylogenetic analyses of early pterosaur species are relatively new and contradictory. However, they imply a similar evolutionary history for early pterosaurs: a large divergence of all major early groups of pterosaurs before the first named pterosaur species appeared in the fossil record. This large, unsampled divergence may be a record of the initial adaptive radiation of the pterosaurs, but a recent comprehensive phylogenetic analysis reconstructs named Triassic pterosaur species grouped together in a monophyletic clade with all other major groups diverging later. Ten patterns that characterize adaptive radiations put forward by Gavrilets and Losos (2009) are assessed for congruence with the comprehensive phylogeny and two previous phylogenies to determine which are consistent with our notions of an adaptive radiation. Of the eight patterns that can be applied to pterosaurs, only six vary between pterosaur phylogenies. Of these six patterns, all apply to the three phylogenies with varying amounts of support. For many patterns, however, the comprehensive phylogeny has a greater magnitude, shorter time span, or is the only topology within which they can be assessed. Pterosaurs are characterized by an adaptive radiation no matter which phylogeny is considered, but congruence with the fossil record increases the support and information content of a phylogeny by reducing the time and area within which to reconstruct evolutionary history.

Abstract:In the years since the first description of a pterosaur specimen in 1784, pterosaur research has inevitably advanced considerably. However the last decade has arguably seen a much greater increase in our knowledge than the preceding two centuries. Since the turn of the new millennium, more than 40 new pterosaur genera and species have been described and whole new clades have been discovered, in addition to much new data being developed on pterosaur anatomy, functional morphology, palaeobiology, systematics, ecology and more. We are perhaps at the start of a golden age of pterosaur research and much as the dinosaurs underwent a revolution in the 1970s through to the early 1990s, now the Pterosauria are taking their turn. There is also a new and wider interest in pterosaur work as it attracts both more researchers and greater public interest. Pterosaurs appear to be an increasingly popular aspect of paleontology in popular culture and of interest to the media, both mainstream and digital.

Abstract:Tapejara wellnhoferi, a small azhdarchoid pterodactyloid from the Early Cretaceous Santana Formation of Brazil, provides critical information about the aerodynamic function of its spectacular head crest. The cranial crests in pterodactyloids were sexually dimorphic and are thought to have evolved in adult males in response to female mate choice. However, the location of cranial crests in front of the center of gravity would create instability in the yaw axis during flight and may seem like a handicap. Vertically aligned webbed feet probably suppressed the yawing rotations and instability from the crest. Here we show that the crest functioned as a front rudder to make agile turn and mediate flight control. A computer simulation model suggests that Tapejara had a large excess of muscle power available above the power required for continuous flapping flight. It could easily takeoff from a perch, ground, or water surface and land safely on the ground. It was an excellent glider with a gliding angle close to 4o and a cruising speed of 27 km/h. Tapejara could soar efficiently on the windward side of cliffs or circle on rising thermals over tropical waters for efficient long-distance flight. Various control surfaces in the wings of Tapejara analogous to the slat, aileron, elevator, fin, rudder, and horizontal stabilizer of an aircraft made pterodactyloids versatile flyers.

Abstract:Prejanopterus curvirostra, from the Early Cretaceous of La Rioja province, was the first pterosaur genus and species described from Spain. The material comprises disarticulated cranial and postcranial remains from several individuals. The fossil-bearing bed is assigned to the lacustrine Leza Formation (eastern Cameros Basin, NW margin of the Iberian Range). This unit is regarded as either Berriasian-Valanginian or Barremian-Aptian. Prejanopterus curvirostris (specific name emended) was originally diagnosed on the basis of several characters of which the most significant was a lateral curvature of the rostrum. Re-examination of the holotype (rostrum) and paratype (partial rostrum with teeth) indicates that there is no genuine sideways bend of the preserved premaxilla-maxilla segments, but a slight dorsal curvature. Prejanopterus is characterized by a unique combination of characters: an emended diagnosis is provided. In contrast with previous estimates, the wing span of Prejanopterus was probably not much (if ever) in excess of 2 m. A phylogenetic analysis suggests that Prejanopterus is a basal pterodactyloid positioned between Pterodactylus and Cycnorhamphus-Gallodactylus. Prejanopterus represents the first evidence of Pterodactylidae in the Early Cretaceous of the Iberian Peninsula.

Abstract:In the tails of dromaeosaurid dinosaurs and rhamphorhynchid pterosaurs, elongate osteological rods extend anteriorly from the chevrons and the prezygapophyses. These caudal rods are positioned in parallel and are stacked dorsoventrally. The fully articulated and three-dimensionally preserved caudal series of some dromaeosaurid specimens show that individually these caudal rods were flexible, not rigid as previously thought. However, examination of the arrangement of the caudal rods in cross-section indicates that the combined effect of multiple caudal rods did provide substantial rigidity in the dorsoventral, but not in the lateral, plane. The results of digital muscle reconstructions confirm that dromaeosaurids and rhamphorhynchids also shared greatly reduced caudofemoral muscles in the anterior tail region. The striking similarities between the tails of dromaeosaurids and rhamphorhynchids suggest that both evolved under similar behavioral and biomechanical pressures. Combined with recent discoveries of primitive deinonychosaurs that phylogenetically bracket the evolution of dromaeosaurid caudal rods between two arboreal gliding/flying forms, these results are evidence that the unique caudal morphologies of dromaeosaurids and rhamphorhynchids were both adaptations for an aerial lifestyle.

Abstract:The Mobarak Formation is near the town of Kiyasar in the south-east of Sari city, northern Iran. This formation conformably overlies the Geirud Formation (Upper Devonian). The lower part of the Mobarak Formation consisting of shales and thin- to medium-bedded limestone toward the top of these sequences changes into alternations of dark limestone and interbedded gray to black shales. Weathered yellow thick-bedded shales are observed at the top of the section. This formation is covered unconformably by sandstones attributed to the Dorud Formation (Lower Permian). The thickness of the formation in this region is 250 m. Four rock units have been recognized in this section. Foraminiferal biostratigraphy shows that the age of the Mobarak Formation in the Kiaysar region ranges from Lower Tournaisian to Early Middle Visean. The foraminifer Zones FAZ1 and FAZ2 are correlated with the Lower Tournaisian and Upper Tournaisian, whereas Zones FAZ3 and FAZ4 correlate with the Visean. Affinities exist between specimens recorded in the Kiyasar section with species known from other regions in eastern and Central Alborz, but there are important differences in their appearance.

Abstract:We identified a total of 101 species and two subspecies of radiolarians belonging to 56 genera from 95 samples collected from the Hagjeon and Duho Formations in the Pohang Basin of the southeastern Korean Peninsula. On the basis of the biostratigraphic range of Cyrtocapsella cornuta and Theocorys redondoensis, the depositional period of the upper Hagjeon and lowest Duho Formations was determined to be early to late Middle Miocene. The occurrence of deep-dwelling radiolarians indicates that the paleobathymetry seems to become gradually progressing toward an upper bathyal environment in the middle part of the Hagjeon Formation. However, we prefer to accept another interpretation for the occurrence of deep-sea indicators in the Hagjeon and the lowest part of the Duho Formations, and consider the presence of a region of upwelling cold water that might have simulated a deep-water environment in relatively shallow water. This interpretation is based on the present upwelling of a cold-water mass off the southeast coast of Korea, the occurrence of upwelling microfossils from the Pohang Basin, and the effect of the closing of the Korea Strait approximately 15 Ma. We also considered that the uppermost part of the studied section represents a shallow-water environment.

Abstract:Calcareous nannoplankton biostratigraphy has been performed on five sedimentary sections through the marine Akveren Formation from the Bartin region of northern Turkey, on the southern Black Sea coast. This new biostratigraphy provides an age for the formation of the Early Campanian (nannofossil zone UC15aTP) to Early Selandian (nannofossil zone NP5), and highlights the presence of the Campanian/Maastrichtian, Cretaceous/Tertiary (K/T), and Danian/Selandian boundaries in this intermediate palaeolatitude location. Micula murus was identified below the K/T boundary, but Micula prinsii and Nephrolithus frequens were not, which implies that the K/T boundary interval is not complete in the study area. These dates are in agreement with previous micropaleontological studies.

Abstract:Metazoan fossils in the Gaojiashan Biota are famous for being well preserved and may provide new insights into the early evolution and skeletonization of Metazoans. We are studying the isotopic compositions of organic and carbonate carbon from a sequence of sedimentary rocks at the Gaojiashan section, northern Yangtze Platform, Shaanxi Province of China. Organic carbon isotope values display a range between –30.8‰ and –24.7‰ with clear stratigraphic variations. Carbonate carbon isotope data vary between 0.1‰ and +6‰. Positive δ13C values from sediments with Gaojiashan biota reflect temporal variations in carbon turnover, i.e. an increasing in photosynthetic carbon fixation followed by an increasing subsequent fractional organic carbon burial, and that related to bio-radiation such as increasing algae, bacteria, and original creatures productivity in biomass. These secular variations are interpreted to reflect perturbations of the regional carbon cycle, specifically changes in the fractional burial of organic carbon, and discuss the relationship between Gaojiashan biota and paleoenvrionmental variation.

Abstract:This paper describes the occurrence of dolomite and the mechanism of dolomitization of the Upper Triassic-Lower Jurassic K?z?loren Formation in the autochthonous Bolkardag? unit of the middle Taurus Mountains in south western Turkey. Dolomites were analyzed for geochemical, isotopic and crystallographic variation. Dolomites occur as a replacement of precursor carbonate and cement. The dolomite crystals range from <10 to ~1000 μm existing as both replacements and cements. Sr concentrations range between 84 and 156 ppm, and the molar Sr/Ca ratios of dolomitizing fluids are estimated to range between 0.0066 to 0.013 ratios. Dolomites are Ca-rich (with average CaCO3 and MgCO3 equal to 56.43 and 43.57 mol%, respectively) and they are non-stoichiometric, with an average Sr=116 ppm, Na=286 ppm, Mn=81 ppm, Fe=1329 ppm, and δ18O and δ13C ranges from –0.6‰ to –6.1‰ Pee Dee Belemnite [PDB], and +1.2 to +3.9‰ PDB. The North American Shale Composition [NASC]-normalized rare earth element (REE) values of the both limestone and dolomite sample groups show very similar REE patterns characterized by small positive Eu (mean=1.32 and mean=1.42, respectively) and slightly or considerably negative Ce (mean=0.61 and mean=0.72, respectively) anomalies and a clear depletion in all REE species. The K?z?loren Formation dolomites have been formed as early diagenetic from mixing zone fluids at the tidal-subtidal environment and at the late diagenetic from basinal brines at the shallow-deep burial depths.

Abstract:Blueschist exposed in the northwestern Qiangtang terrane, northern Tibet, western China (~84°30′ E, 34°24′ N), provides new constraints on the tectonic evolution of Qiangtang as well as northern Tibet. The blueschist represented by lawsonite- and glaucophane-bearing assemblages equilibrated at 375–400 °C and ~11 kbar. 40Ar-39Ar analysis on mineral separate from one blueschist sample yielded a well-defined plateau age of ~242 Ma. Geochemical studies show the blueschist is metamorphosed within-plate basalts. The high pressure-low temperature blueschist indicates a Triassic event of lithosphere subduction, and clearly represents an extension of the central Qiangtang metamorphic belt, and defines an in?situ suture between eastern and western Qiangtang.

Abstract:The Zhou’an PGE-Cu-Ni deposit was recently discovered in the Qinling orogenic belt bound by the Yangtze and the North China Cratons. It is a blind deposit thoroughly covered by the Cenozoic alluvial sediments in the Nanyang Basin. As the first large PGE-Cu-Ni deposit discovered in the Qinling-Dabie-Sulu orogenic belt, its geological and geochemical characteristic, isotope age, genesis and tectonic setting are of wide concern in both scientific studies and ore exploration. In this contribution, we report the results obtained from a pioneering study. The Zhou’an ultramafic complex is ferruginous, with m/f?=?4.79–5.08, and shows the nature of tholeiite series. It is rich in light rare earth elements, Rb, Th, U, La, Sm, Zr and Hf, and poor in heavy rare earth elements, Nd and Ta, suggesting an intraplate setting. It has high 87Sr/86Sr and low 143Nd/144Nd ratios. The ratios of Zr/Nb, La/Nb, Ba/Nb, Rb/Nb, Th/Nb, Th/La and Ba/La, suggest the magma originated from lithosphere mantle. The Fo values of olivine and Pd/Ir-Ni/Cu diagram suggest primary magma was High Mg basalt. The laser ablation inductively coupled plasma atomic emission spectroscopy zircon U-Pb age is 641.5?±?3.7 Ma.

Abstract:The Yangla copper deposit, located in western Yunnan Province, China, is a typical giant, newly started mining copper deposit with an estimated Cu reserves of about 1,200,000 tons. The deposit is spatially and temporally associated with the Linong granodiorite, which is rich in SiO2 (SiO2=58.25 wt%–69.84 wt%) and alkalis (Na2O+K2O=5.98 wt%–8.34 wt%), indicating an association with shoshonitic series to high-K calc-alkaline series granites, and shows low contents of TiO2 (0.35 wt%–0.48 wt%), MgO (1.51 wt%–1.72 wt%), and Al2O3 (13.38 wt%–19.75 wt%). The δ34S values of sulfides of the main ore stage from copper ores vary range from ?4.2‰ to ?0.9‰, indicating a much greater contribution from the mantle to the ore-forming fluids. The δ34S values of the late ore stage is ?9.8‰, indicating enrichment of biogenic sulfur which may derive from the crustal hydrothermal fluid. The 208Pb/204Pb, 207Pb/204Pb and 206Pb/204Pb of sulfides of the main ore stage from copper ores range within 38.66–38.73, 15.71–15.74 and 18.35–19.04, respectively, implying that the Pb was derived from the mantle, with the crustal component, probably representing mixtures of mantle lead and crustal lead. Sulfide of the late ore stage in their Pb isotopic composition, 208Pb/204Pb= 38.69, 207Pb/204Pb=15.70, 206Pb/204Pb=18.35, implying that the Pb was derived from the crust. The Linong granodiorite is syn-collisional, produced by partial melting of thickened lower crust, which was triggered by the westward subduction of the Jinshajiang Oceanic plate. During a transition in geodynamic setting from collision-related compression to extension, gently dipping ductile shear zones (related to subduction) were transformed to brittle shear zones, consisting of a series of thrust faults in the Jinshajiang tectonic belt. The tensional thrust faults would have been a favorable environment for ore-forming fluids. The ascending magma provided a channel for the ore-forming fluid from the mantle wedge. After the magma arrived at the base of the early-stage Linong granodiorite, the platy granodiorite at the base of the body would have shielded the late-stage magma from the fluid. The magma would have cooled slowly, and some of the ore-forming fluid in the magma would have entered the gently dipping thrust faults near the Linong granodiorite, resulting in mineralization.

Abstract:Diabase dyke swarms are widespread in the East Tianshan and Beishan regions. LA-ICP-MS zircon U-Pb ages of these diabase vary from 305 Ma to 278 Ma, showing that these dykes were formed during Late Carboniferous-Early Permian magmatism. All diabase samples are subalkali calc-alkali, characterized by slight LREE and LILEs enrichment, and weak negative Ti, Nb and Ta anomalies. The diabase samples have positive εNd(t) values (>+3), high Sr isotopic compositions (initial 87Sr/86Sr values=0.7030-0.7097), and large variation of Pb isotopic compositions, indicating they were derived from a deplete mantle source. Regional geology and geochemistry evidences indicate that these diabase dyke swarms were generated in a lithosphere extensional setting and had the same magma sources. Initial magmas may be a mixture of depleted asthenosphere mantle and enriched lithospheric mantle during rapid magma ascending.

Abstract:Chemical and isotopic compositions have been measured for N2-He-rich bubbling gases discharging from hot springs in the Hainan Island, Southern China. Observed 3He/4He ratios (0.1–1.3 RA) indicate the occurrence of a mantle component throughout the island, which has been highly diluted by a crustal radiogenic 4He component. The occurrence of mantle-derived helium is high in the northern island (12%–16% of total He) and gradually decreases towards southern coast (1%–3% of total He). Such a distribution pattern is most likely controlled by the Pleocene-Quaternary volcanic activities in the northern island and groundwater circulation along the deep major faults. The 40Ar/36Ar and N2/Ar ratios suggest that N2 and Ar of the hot spring gases are mostly meteoric. Although δ13C values of CO2 (–20‰ to –27‰) with low concentrations are consistent with the biogenic origin, the combination of 3He/4He and d13CCO2 suggests a two end-member mixing of mantle and crustal components with CO2/3He ratios of 2×109 and 8×1011, respectively. However, the low CO2/3He ratios (1–22×106) can not be ascribed in terms of the simple mixing but has to be explained by the addition of radiogenic 4He and loss of CO2 by calcite precipitation in the hydrothermal system, which is most likely controlled by the degree of gas-water-rock interaction.

Abstract:The crystal structure of ludwigite from Vranovac ore deposit (Boranja Mt., Serbia) was refined using the X-ray powder diffraction (XRPD) Rietveld method in the space group Pbam to a final RB=7.45% and RF=5.26%. It has the unit cell dimensions of: a=9.2515(2) ?; b=12.3109(2) ?; c=3.03712(7) ?; and V=345.91(1) ?3. The calculated distances and angles are mostly in good agreement with the Mg2+-Fe2+ substitutions across the M(1) and M(3) sites, as well as with the Fe3+-Al3+ replacement in the M(4) site. However, the mean observed M(2)-O distance is considerably shorter than prescribed, due to a slight increase of the Fe3+ content in the M(2) site. Such replacement was compensated by slight increase of the Fe2+ content in the M(4) site, resulting in the (Mg1.48Fe2+0.46Fe3+0.05Mn0.02)2.01(Fe3+0.94Fe2+0.04Al0.02)1.00B1.00O5 composition. The formation temperature was estimated to be about 500–600°C. The influences of the various chemical compositions to the crystallographic parameters, M-O distances, M(3) and M(4) sites shift, distortion parameters and estimated valences, were also studied and compared with other reference samples.

Abstract:Shuidonggou site has abundant Paleolithic remains of Late Pleistocene deposition. Studying the evolution of depositional environments is essential to the comprehensive understanding of the living conditions of ancient populations. To reconstruct the depositional environment at Shuidonggou, we carried out archaeological excavations and collected systematic deposition samples at the key position of Shuidonggou Locality 2 for grain size analysis and sporopollen statistics. The environmental evolution around the Shuidonggou site generally underwent four stages at ~72–18 kaBP. During the first stage (~72–41 kaBP), the river developed with gravel and sand stratums. During the second stage (41~34 kaBP), a swamp with numerous aquatic plants formed. In the third stage (34–29 kaBP), site formation was characterized by shallow lake depositional conditions; the climate was relatively warm and humid. The marginal bank depositional conditions deteriorated during the fourth stage (29–18 kaBP), and the site underwent several dry events; the climate also became drier and colder.

Abstract:A study of faults and their control of deep gas accumulations has been made on the basis of dividing fault systems in the Xujiaweizi area. The study indicates two sets of fault systems are developed vertically in the Xujiaweizi area, including a lower fault system and an upper fault system. Formed in the period of the Huoshiling Formation to Yingcheng Formation, the lower fault system consists of five fault systems including Xuxi strike-slip extensional fault system, NE-trending extensional fault system, near-EW-trending regulating fault system, Xuzhong strike-slip fault system and Xudong strike-slip fault system. Formed in the period of Qingshankou Formation to Yaojia Formation, the upper fault system was affected mainly by the boundary conditions of the lower fault system, and thus plenty of multi-directionally distributed dense fault zones were formed in the T2 reflection horizon. The Xuxi fault controlled the formation and distribution of Shahezi coal-measure source rocks, and Xuzhong and Xudong faults controlled the formation and distribution of volcanic reservoirs of Y1 Member and Y3 Member, respectively. In the forming period of the upper fault system, the Xuzhong fault was of successive strong activities and directly connected gas source rock reservoirs and volcanic reservoirs, so it is a strongly-charged direct gas source fault. The volcanic reservoir development zones of good physical properties that may be found near the Xuzhong fault are the favorable target zones for the next exploration of deep gas accumulations in Xujiaweizi area.

Abstract:Hydrocarbon distribution rules in the deep and shallow parts of sedimentary basins are considerably different, particularly in the following four aspects. First, the critical porosity for hydrocarbon migration is much lower in the deep parts of basins: at a depth of 7000 m, hydrocarbons can accumulate only in rocks with porosity less than 5%. However, in the shallow parts of basins (i.e., depths of around 1000 m), hydrocarbon can accumulate in rocks only when porosity is over 20%. Second, hydrocarbon reservoirs tend to exhibit negative pressures after hydrocarbon accumulation at depth, with a pressure coefficient less than 0.7. However, hydrocarbon reservoirs at shallow depths tend to exhibit high pressure after hydrocarbon accumulation. Third, deep reservoirs tend to exhibit characteristics of oil (–gas)–water inversion, indicating that the oil (gas) accumulated under the water. However, the oil (gas) tends to accumulate over water in shallow reservoirs. Fourth, continuous unconventional tight hydrocarbon reservoirs are distributed widely in deep reservoirs, where the buoyancy force is not the primary dynamic force and the caprock is not involved during the process of hydrocarbon accumulation. Conversely, the majority of hydrocarbons in shallow regions accumulate in traps with complex structures. The results of this study indicate that two dynamic boundary conditions are primarily responsible for the above phenomena: a lower limit to the buoyancy force and the lower limit of hydrocarbon accumulation overall, corresponding to about 10%–12% porosity and irreducible water saturation of 100%, respectively.

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