Revision of the Conchostracan Genus Tenuestheria from the Upper Cretaceous Lanxi Formation in Zhejiang and Its Biostratigraphic Significance in Southeast China

The diagnosis of the conchostracan genus Tenuestheria from the Lanxi Formation in Jinhua, Zhejiang Province in Southeast China is revised following an examination of the type species under a scanning electron microscope, which revealed some morphological features on the carapace that had not been recognized previously. The importance of the Tenuestheria Fauna is considered in the context of correlation of six Turonian-Santonian formations in this region of China. The value of the Cenomanian Nemestheria and Turonian Linhaiella faunas in correlating the underlying early Late Cretaceous formations is also noted.

Pore Characteristics and Factors Controlling Lacustrine Shales from the Upper Cretaceous Qingshankou Formation of the Songliao Basin,Northeast China:A Study Combining SEM,Low-temperature Gas Adsorption and MICP Experiments

To investigate pore characteristics and the factors controlling lacustrine shales,geochemical,mineralogical and petrophysical experiments were performed on 23 shale samples from the Qingshankou Formation of the Songliao Basin,China.A comparison of mercury injection capillary pressure(MICP)and low-temperature N2 adsorption pore-size distribution showed that MICP has a higher pore-size distribution(PSD)line in its overlapping pore diameter range,which may be elevated by the higher pressure of MICP.Therefore,in the overlapping range,low-temperature N2 adsorption data were preferred in pore characterization.Negative correlations were observed between pore volumes and TOC content,indicating organic matter pores are not well-developed in the studied samples.This may be related to their low grade of maturity and type I kerogens.There existed negative relationships between pore volumes and S1,which illustrated that liquid hydrocarbons occupied some pore space.Micropore volume had a better correlation with S1 than mesopore and macropore volumes,which suggests that liquid hydrocarbons preferentially occur in micropores.No obvious relationships between pore volumes and quartz or feldspar were observed,while pore volumes increased with the increasing clay mineral content.These relationships indicate that intraparticle pores in clay minerals represent the principal pore type.

Quantitative Biostratigraphic Analysis upon the Upper Cretaceous in Tethyan Himalaya

Biostratigraphic analysis is an essential element for understanding global tectonics and the evolution of life on Earth. Quantitative analysis of sedimentary sequences provides the precise age constraints on timing of significant events in Earth＇s history. This paper presents results from quantitative stratigraphic analysis of Upper Cretaceous Tethyan Himalayan sequences. This analysis resulted in a new composite stratigraphic section for the Cretaceous strata of Tibet （TIBETKCS）. The eight Upper Cretaceous sections were analyzed in this study and 12 planktonic foraminifera zones were recognized based on available data. Quantitative measurements were made using a Graphic Correlation with Graphcor 3.0 software and correlated to the world standard Cretaceous Composite Section （MIDKCS）. The sections were also examined using Constrained Optimization software by CONOP9. Level Penalty was applied as the rule to measure misfit among automatically correlated sections. The new TIBETKCS correlates well with planktonic foraminifera ages from previous work in southern Tibet. A fitting equation of y=？0.19x＋305 with a correlation coefficient of 0.94 was obtained from this work. The ages of the first and last appearances of 64 planktonic foraminifera can be calculated with this equation with ± 0.3 Ma precision. This level of precision is approximately 10 times higher than age determinations with traditional methods. Two extinction events were resolved within this analysis at ~93.5 Ma and ~85.5 Ma corresponding to the Ocean Anoxic Events at Cenomanian-Turonian and Coniacian-Santonian boundaries respectively.

Clay Mineralogical and Geochemical Studies of Detrital Rocks of the Upper Cretaceous Salt-bearing Strata,Simao Basin,SW China:Implication for Provenance and Source Weathering

1 Introduction Geological studies established on several sections in Lanping-Simao basin have shown that the salt-bearing strata of Mengyejing formation(Yunlong Fm.in Lanping basin)are constituted by an alternation of salt layers and interbedded facies.The latter consists mainly of mudstones,and mudstone-rich conglomerate.The mineralogy and geochemistry of salt-bearing beds and

Palynostratigraphy of Upper Cretaceous and boundary Paleogene deposits in West Siberian Plain

The article presents the results of many years of studies of the Upper Cretaceous and Paleogene sediments in the territory of West Siberian Plain. The heterogeneous structure of these sediments in different regions of the plain is shown. The lithological and palynological characteristics of a number of studied wells drilled in different years in Omsk and Kulunda Depressions, in Baraba Lowland and Bakchar Basin are given. The obtained palynological data allowed to substantiate the age of the deposits and to make suggestions concerning their depositional environment, and to clarify the subdivision of geological section into formations. The sections of the Upper Cretaceous and Paleogene deposits in different lithofacial regions of the Western Siberia differ from each other in completeness, genesis, and paleontological characteristics. The Upper Cretaceous sediments in Western Siberia are represented by formations of both marine(Pokur, Kuznetzovo, Ipatovo, Slavgorod and Gan'kino Formations) and continental genesis(Lenkovo and Sym formations). The Paleogene sediments, with the exception of Oligocene, mostly have a marine genesis-these are Talitsa-, Marsyat-, Lulinvor-, Tavda-and Yurki formations, but there are also continental sediments(Ostrovnoje Formation). A large stratigraphic break in the Upper Cretaceous and Paleogene boundary deposits, covering a significant part of the Maastrichtian, Paleocene, Ypresian, and Lutetian stages of the Eocene, was established in the sourheast of the West Siberian Plain(Bakchar Basin, Baraba Lowland and Kulunda Depression). The most complete sections are located in the Omsk Depression, where the Upper Cretaceous Gan'kino Formation is covered by Talitsa and Lulinvor Formations of Paleogene age. The most important events occurring at the boundary of the Cretaceous and Paleogene in Western Siberia can be traced currently in a few sections located in the Trans-Ural area, since there was no sedimentation in the rest of the territory at that time.

Lacustrine high resolution sequence records from Upper Cretaceous Nenjiang Formation in Songliao Basin

The Nenjiang Formation was continuously cored in the SK-1 borehole(China Cretaceous Continental Scientific Drilling Project-SongKe1well).Over 95.7%recovery rate,the obtained continuous core is 827.6 m in length,covering the geological age ranges from late Santonian to middle Campanian.This is the most complete and continuous sedimentary deposits in the Songliao basin till now.Here we systematically presented the lithological results of the observation of the cores in 2--5 cm thickness scale at the drilling spot,and the analysis on lithofacies and sedimentary sequence,cyclic stratigraphy.13 types of sedimentary rocks deposited mainly in lacustrine,delta and fluvial environments were found in the Nenjiang Fromation,and they were subdivided into 19 microfacies including dolomite,marl,argillaceous limestone,turbidite,mudstone of still water,volcanic ash,channel-lag deposit,point bar,natural levee,crevasse splay,crevasse channel,floodplain,flood lake,distributary mouth bar,subaqueous distributary channels,subaqueous natural levee,subaqueous inter-distributary bay,distal bar and adjacent shore sand bar.The whole sedimentary column is composed of 630 sixth-order depositional cycles in the meter-scale,which can be further organized in 148 fifth-order depositional cycles,38 fourth-order depositional cycles and 5 third-order depositional cycles.Meticulous depiction(centimeter level)of the whole Formation provides an approach to study its sedimentary process with high precision.The centimeter-scale description of the sequent core presented some previously unidentified dolomite and volcanic ash layers.The cyclostratigraphy of the Nenjiang Formation was controlled by Milankovitch cycled,which is helpful to discover the climatic changes of the late Santonian to the middle Campanian in Songliao Basin.In addition,the detailed description of the sequent section is significant for the upcoming oil and gas exploration in the Songliao Basin if regarding the new type of oil/gas systems.

Fossil Stomatocysts in Upper Cretaceous Sedimentary Pyrite from Central Mexico

In this paper six fossil forms of Chrysophycean stomatocysts are described. The material was collected from sedimentary pyrite embedded in well-laminated organic-rich limestone of the Upper Cretaceous Agua Nueva Formation at the locality of Xilitla, Central Mexico. The stomatocysts are represented by two spherical specimens with smooth surfaces lacking of ornamentation, three ovoid forms with rugose textures, one of them exposing presence of pore without collar, and one spherical specimen showing rugose texture and the presence of two short and rounded projections. The specimens here described showed affinity with some stomatocysts morphotypes described for brackish and fresh water, but not for known marine specimens. The presence of these microfossils in the Agua Nueva Formation represents the first formal description of fossil stomatocysts in Upper Cretaceous sedimentary pyrite in Mexico. The occurrence of both micro (planktonic foraminifera, calcispheres, radiolarians) and macrobiota (ammonites, inoceramid bivalves and fishes) and the presence of the specimens in sedimentary pyrite suggest that the stomatocysts were preserved under oxygen-deficiency conditions in a low energy environment. This event could have occurred in open marine waters in the Tampico-Misantla basin (Central Mexico) during the late Cenomanian throughout the early Turonian.

Flat-footed Females and Missing Males:A New Genus and Species of Pleciofungivoridae(Diptera:Bibionomorpha)Represents the First Record of the Family from Mid-Cretaceous Kachin Amber

A new genus and species,Cretopleciofungivora simpsoni gen.et sp.nov.,from the extinct family Pleciofungivoridae(Diptera:Bibionomorpha),is discovered in mid-Cretaceous Kachin amber.Previously,this family was known only from imprints in sedimentary rocks of the Jurassic and the Lower Cretaceous.Discovery of a representative of Pleciofungivoridae in Kachin amber confirms the presence of the family in the Upper Cretaceous.The new species has a unique structure of fore tarsus,with lobed and extended tarsal segments Ⅱ to Ⅳ,a feature hitherto known only in a few species of extant Sciaroidea.Although not particularly rare,the new species is currently known only from female specimens.Possible reasons for this phenomenon,very unusual in Sciaroidea,are briefly discussed,including parthenogenesis as a potentially plausible hypothesis.

Siliciclastic-carbonate mixing modes in the river-mouth bar palaeogeography of the Upper Cretaceous Garudamangalam Sandstone(Ariyalur, India)

Mixed siliciclastic-carbonate rocks constitute the Upper Cretaceous Garuda- mangalam Sandstone Formation, Ariyalur （India）, and offer an opportunity to look into the broad spectrum of mixing of compositionally and genetically different components. The palaeogeographic reconstruction indicates that deposition in the nearshore zone differed strongly in energy and active processes operatives due to the presence of a shore-parallel river-mouth bar. The western wing of the Mississippi bird-foot delta is considered to be a present-day analogon. Facies analysis in combination with petrography clearly shows the variability in palaeoenvironmental characteristics, both biogenic and non-biogenic. It also indicates dia- genetic uptake of carbonate that filled empty spaces and actively replaced original compo- nents. Chemical staining followed by limited application of cathodoluminescence and energy dispersive X-ray analysis （EDAX） hint at intricacies in mixing arising from the compositional variations in the carbonate components. A model of siliciclastic-carbonate sediment mixing, including both the depositional and diagenetic developments, is presented; it is aimed at generating a better overview of, and a deeper insight into, the physical and chemical mechanisms involved.

A probable tyrannosaurid track from the Upper Cretaceous of southern China

A large number of Upper Cretaceous(Maastrichtian)dinosaur skeletal fossils have been found in the Nanxiong Basin and adjacent Ganzhou area,including those of theropods,sauropods and hadrosaurids.However,known dinosaur ichnoassemblages from the Nanxiong Basin partly indicate a different fauna,with dominating large-and medium-sized ornithopods,theropods,and pterosaurs(1,2)This is one of many known examples where trace and body fossil assemblages from the same formation or geologically discrete region show a different composition.Palecological and paleobiogeographical analyses therefore should consider data from both,before any conclusions can be drawn.Formations can be classified according to the relative degree of similarity or congruity(or difference/incongruity)between trace and body fossils into the 5 categories proposed by Lockley[3].

A New Oviraptorid Dinosaur (Theropoda: Oviraptorosauria) from the Late Cretaceous of Jiangxi Province, Southern China

A new oviraptorid dinosaur Jiangxisaurus ganzhouensis gen. et sp. nov., is erected based on a partial skeleton from the Upper Cretaceous Nanxiong Formation of Ganzhou City, Jiangxi Province. The new taxon differs from other oviraptorids in the weakly downturned rostrum of the lower jaw, much-elongated mandible with a height-to-length ratio being about 20% and the length ratio of radius to humerus of about 0.70. This species not only adds a new member to oviraptorid dinosaurs, but also provides more information about oviraptorid paleogeographical distribution in southern China.

New understanding and exploration direction of hydrocarbon accumulation in Termit Basin, Niger

Based on the seismic and drilling data, casting thin sections, geochemical analysis of oil and rock samples, and hydrocarbon generation history simulation, the hydrocarbon accumulation characteristics and exploration direction of Termit superimposed marine–continental rift basin are discussed. The Termit basin is superimposed with two-phase rifts(Early Cretaceous and Paleogene). The subsidence curves from two wells on the Trakes slope in the east of the basin show high subsidence rate in the Late Cretaceous, which is believed to be high deposition rate influenced by transgression. However, a weak rift may also be developed. The depositional sequences in the Termit basin were controlled by the Late Cretaceous marine transgression cycle and the Paleogene lacustrine transgression cycle, giving rise to two types of superimposed marine–continental “source-sink” deposits. The marine and continental mixed source rocks developed universally in the whole basinduring the marine transgression period, and are overlaid by the Paleogene Sokor 1 reservoir rocks and Sokor 2 caprocks developed during the lacustrine transgression period, forming the unique superimposed marine–continental basin in WCARS. The early low geothermal gradient in the Termit basin resulted in the late hydrocarbon generated by the source rock of Upper Cretaceous Yogou in Paleogene. Mature source rock of Upper Cretaceous Donga developed in the Trakes slope, so that the double-source-supply hydrocarbon and accumulation models are proposed for the Trakes slope in which formed the oil fields. Due to virtue of the newly proposed hydrocarbon accumulation model and the exploration activities in recent years in the Termit superimposed marine–continental rift basin, an additional effective exploration area of about 2500 km2has been confirmed in the east of the basin. It is believed that potential domains such as Sokor 1, Donga and Upper Cretaceous lithologic traps in the southeast of the basin are key expected targets for exploration and frontier evaluation in future.

Oviraptorosaurian Eggs (Dinosauria) with Embryonic Skeletons Discovered for the First Time in China

Two elongatoolithid dinosaur eggs from the Upper Cretaceous of Ganzhou, Jiangxi Province and the embryonic skeletons they bear are described. They represent the first oviraptorosaurian eggs with embryonic skeletons in China and provide the first example that an oospecies can be correlated to certain dinosaur taxon/taxa. The two eggs are the same as the pair of the eggs inside a female oviraptorosaurian pelvis from the same horizon of the same area in both macro- and micro-structures of the egg shells, and can he referred to the oospecies, Macroolithus yaotunensis Zhao, 1975. The morphology of the preserved part of the embryonic skeletons indicates that they may have been laid by an oviraptorid, Heyuannia huangi from Guangdong Province or a closely related oviraptorosaurian, which may have been lived in the Ganzhou area too in the Late Cretaceous. The embryonic skeletons of the two eggs are not in the same developing stage. In one of the eggs, the postzygapophysis of the preserved vertebrae are well ossified, indicating that it was just hatched.

Cretaceous dinosaur and crocodylomorph egg records of the Sanshui Basin,Guangdong Province,southern China

This paper describes newly discovered dinosaur and crocodylomorph egg fragments from the Upper Cretaceous Sanshui and Dalangshan formations of the Sanshui Basin of Guangdong Province,southern China.Despite the absence of macroscopic information,the eggshell specimens can be identified to the oofamilies Prismatoolithidae,Elongatoolithidae and Krokolithidae,and it is hypothesized that these three families of eggs correspond to troodontids,oviraptorids and crocodiloids,respectively.Comparison with egg fossils from Nanxiong Basin,Heyuan Basin and Ganzhou Basin highlights the similarity between these egg assemblages and those from Nanxiong Basin.The egg fossils found in the Sanshui and the Dalangshan for-mations enrich the known faunal types in the research area and facilitate further studies on the diversity of Late Cretaceous vertebrate assemblages in the Sanshui Basin.

Repeated occurrence of palaeo-wildfires during deposition of the Bahariya Formation(early Cenomanian) of Egypt

The Upper Cretaceous(early Cenomanian)Bahariya Formation of Egypt has an outstanding reputation for its wealth of vertebrate remains,including a variety of iconic dinosaurs,like the carnivorous Spinosaurus and Carcharodontosaurus,as well as the herbivorous Aegyptosaurus and Paralititan.Besides these dinosaur fossils,the Bahariya Formation yielded also a wealth of invertebrate and plant remains,but even today many aspects concerning the continental palaeoenvironments reflected in these deposits(including the occurrence of palaeo-wildfires)have not been studied in detail.So far six distinct macro-charcoal bearing levels could be identified within the type section of the Bahariya Formation at Gabal El Dist profile,one of the most prolific outcrops of this formation in terms of fossil occurrence located in the north of the Bahariya Oasis,Western Desert,Egypt.Most of the charcoal investigated by means of SEM originates from ferns,pointing to a considerable proportion of this plant group within the palaeo-ecosystems that experienced fires.Gymnosperms and(putative)angiosperms have less frequently been identified.The collected data present evidence that the landscapes at the northern shores of Gondwana repeatedly experienced palaeo-wildfires,adding extra proof to previous statements that the Late Cretaceous was a fiery world on a global scale.

A new oospecies of Shixingoolithus(Shixingoolithus qianshanensis oosp.nov.)from the Qianshan Basin,Anhui Province,East China

Here we describe two newly discovered dinosaur eggs from the Upper Cretaceous Chishan Formation in the Qianshan Basin,Anhui Province,East China.These dinosaur eggs can be assigned to a new oospecies of Stalicoolithidae,Shixingoolithus qianshanensis,based on the following combined features:the larger size of eggs,the uniform eggshell microstructure in the radial section,the smaller height and the larger density of radial microstructures at the inner surface of the eggshell.Radial sections of S.qianshanensis show closely arranged columnar eggshell units forming relatively uniform and dense microstructure;some secondary eggshell units and numerous sub-circular radial microstructures appear separately in the middle and inner parts of the tangential sections,respectively.The discovery of S.qianshanensis provides new fossil types of Stalicoolithidae and represents the first dinosaur relative record in the Qianshan Basin,which offer accurate paleontological evidence of Late Cretaceous-Early Paleocene stratigraphic classification in the Qianshan Basin,Anhui Province.