Late Jurassic-Early Cretaceous Erg Deposits in the Mengyin Basin, Western Shandong Province, China: Inferences about the Wind Regime and Paleogeography

The Late Jurassic-Early Cretaceous Santai Formation, sporadically distributed in western Shandong Province, comprises terrestrial alluvial-eolian successions, which records regional wind patterns and paleogeography in eastern North China. This paper conducts an analysis of eolian stratification, bounding surfaces, facies architecture and paleowind direction of the Santai Formation in the east of the Mengyin Basin, western Shandong Province. Three basic types of eolian stratification are recognized in the Santai Formation, including grainflow strata, wind ripple strata and adhesion strata, and have been grouped into eolian dune and interdune facies associations. The occurrences of reactivation surfaces and superimposition surfaces within eolian dune deposits indicate active compound dunes or draas. The association of adhesion strata with grainflow or windripple strata is the development of a wet eolian system. Cross-strata dip direction indicates different paleowind directions from the lower to the upper part of the Santai paleoerg. The lower part of the paleoerg was characterized by paleowinds blowing from northwest to northeast, whereas the upper part was under the influence of paleowinds consistently towards east to northeast. The identified changes in wind directions possibly suggest wind regime shifts from monsoon circulation to westlies of planetary wind system, which may be related with the collapse of the East China Plateau during the Late Jurassic to Early Cretaceous.

Changes of taxonomical composition of Late Jurassic-Early Cretaceous palynofloras of Bureya Basin,Russia

The changes of taxonomical composition of the Late Jurassic-Early Cretaceous palynofloras are revealed,in the upper stream of Bureya River in Bureya Basin.The palynofloras are dominated as follows:the Berriasian one by ferns(Cyatheaceae,Dicksoniaceae,Osmundaceae),Classopollis and bisaccate pollen;the Valanginian-Hauterivian one by ferns(Cyatheaceae,Dicksoniaceae),Ginkgocycadophytus and bisaccate pollen;the Barremian one by ferns(Cyatheaceae,Dicksoniaceae);the Aptian one by ferns(Cyatheaceae,Dicksoniaceae,Gleicheniaceae) and Ginkgocycadophytus;and the Albian one by ferns(Schizaeaceae) and bisaccate pollen.In the Albian the floral diversity raises with the angiosperms appearing.

Late Jurassic-Early Cretaceous tectonic switching in Liaodong Peninsula of the North China Craton and the implications for gold mineralisation

Constraining the processes of deformation during tectonic switching from compression to extension is difficult because of the scarcity or absence of associated sedimentary and magmatic rocks and weak metamorphism.The east margin of the eastern North China Craton experienced Early to Middle Jurassic compression and Early Cretaceous extension.However,the period of tectonic quiescence lasting~13 million years(between 153 and 140 Ma)during which this transition occurred is poorly understood.This paper reports the identification of small-scale N-S-trending thrust and sinistral strike-slip faults(TSS)and NWtrending thrust and dextral strike-slip faults(TDS)in the Tongyuanpu-Aiyang region,which is part of the northern Liaodong Peninsula.Calculation of the tectonic stress field using striations,fault planes and kinematics reveals a NW-SE-oriented maximum principal axis(σ1),and sub-horizontalσ2 andσ3.Assemblages of N-S-trending TSS and NW-trending TDS were arranged with right stepping and resulted in local uplift and erosion at the junctions between fault terminations,which partitioned the Early and Middle Jurassic basins into residual smaller volcanic-sedimentary basins.These basins were unconformably overlain by small Early Cretaceous volcanic-sedimentary basins,such as those at Tongyuanpu and Fangjiaweizi.Magmatic ages and the timing of basin formation constrain the initiation of tectonic switching to 156–153 Ma,and its termination to 140–139 Ma.We suggest that R-R’Riedel shears controlled the formation of the N-S-trending TSS and NW-trending TDS.The R-R’shears were produced by continued sinistral strike-slip and northward growth along the Bohai Bay segment of the Tan-Lu fault zone during the Late Jurassic to early Early Cretaceous,simultaneous with a gradual weakening in the tectonic stress field during a switch in the direction of subduction of the Palaeo-Pacific plate from NW-ward to NNW-ward.This tectonic switching might have promoted the dissolution of gold and migration of gold-bearing fluids.

The sedimentary record of the Sanshui Basin:Implication to the Late Cretaceous tectonic evolution in the northern margin of South China Sea

Whether the South China continental margin had shifted from active subduction to passive extension in the Late Cretaceous remains controversial.Located in the northernmost of the South China Sea continental margin,Sanshui Basin developed continuous stratigraphy from Lower Cretaceous to Eocene and provides precious outcrops to study the regional tectonic evolution during the Cretaceous.Therefore,we conducted field observations,petrology,clay mineralogy,geochemistry,and detrital zircon chronology analyses of sedimentary rocks from the Upper Cretaceous Sanshui Formation in Sanshui Basin.Results suggest that the Sanshui Basin is characterized as an intermoutane basin with multiple provenances,strong hydrodynamic environment,and proximal accumulation in the Late Cretaceous.An angular unconformity at the boundary between the Lower and Upper Cretaceous was observed in the basin.The sedimentary facies of the northern basin changed from lacustrine sedimentary environment in the Early Cretaceous to alluvial facies in the Late Cretaceous.The zircon U-Pb ages of granitic gravelly sandstone from Sanshui Formation prominently range from 100 Ma to 300 Ma,which is close to the deposition age of Sanshui Formation.The major and trace elements of the Late Cretaceous sedimentary samples show characteristics of active continental margin,and are different from the Paleogene rifting sequences.Hence,we propose that the northern South China Sea margin underwent an intense tectonic uplift at the turn of the Early and Late Cretaceous(around 100 Ma).Afterward,the northern South China Sea margin entered a wide extension stage in the Late Cretaceous(~100 to~80 Ma).This extensional phase is related to the back-arc extension in the active continental margin environment,which is different from the later passive rifting in the Cenozoic.The transition from active subduction to passive extension in the northern South China Sea may occur between the late Late Cretaceous and the Paleogene.

A Titanosaurian Sauropod Dinosaur with Opisthocoelous Caudal Vertebrae from the Early Late Cretaceous of Liaoning Province, China

We describe a new titanosaurian sauropod dinosaur, Borealosaurus wimani gen. et sp. nov., based on a distinctive mid-distal caudal vertebra from the early Late Cretaceous Sunjiawan Formation exposed in the Shuangmiao village of Beipiao in Liaoning, China. We provisionally refer an isolated tooth crown, a middle caudal vertebra, and a right humerus from the same locality and horizon to this taxon. Borealosaurus is distinguished from other sauropods in its possession of opisthocoelous mid-distal caudal vertebrae. The occurrence of opisthocoelous caudals in Borealosaurus and the Mongolian sauropod Opisthocoelicaudia raises the possibility that these taxa pertain to an as-yet unrecognized titanosaurian subclade endemic to the Cretaceous Asia.

New Nodosaurid Dinosaur from the Late Cretaceous of Lishui, Zhejiang Province, China

A new genus and species of nodosaurid dinosaur： Zhejiangosaurus lishuiensis gen. et sp. nov. is erected herein. It is characterized by the sacrum consisting of at least three true sacral vertebrae, 5 caudal dorsal vertebrae fused to form the presacral rod, wide divergence of long slender preacetabular process of the ilium from the middle line of the body, and the fourth trochanter located at the femoral mid-length.

A New Protoceratopsid (Dinosauria: Neoceratopsia) from the Late Cretaceous of Inner Mongolia, China

An almost complete skull, which was collected from the Upper Cretaceous of the Bayan Mandahu area in Inner Mongolia, China by the Sino-Canadian Dinosaur Project, is described and assigned to a new genus of protoceratopsid dinosaur, Magnirostris dodsoni gen. et sp. nov. This new taxon is distinguished from other protoceratopsids by the robust rostral bone and the existence of incipient orbital horn cores. The existence of an additional antorbital fenestra indicates a close relationship between Magnirostris and Bagaceratops.

A New Titanosauriform Sauropod from the Early Late Cretaceous of Dongyang,Zhejiang Province

A new titanosauriform sauropod Dongyangosaurus sinensis gen. et sp. nov. from the early Late Cretaceous of Dongyang County, Zhejiang Province, is erected based on a partial postcranial skeleton. It is characterized by complex laminae on the lateral surface of the neural spines and postzygapophyses of dorsal vertebrae, a distinct fossa on the ventral surfaces of the prezygapophyses of dorsal vertebrae, distinct fossae are also present on the lateral surface of the postzygapophysis of anterior caudal vertebrae; pubis is shorter than ischium, the small obturator foramen of pubis elongated, and nearly closed. The lamina complexity of dorsal vertebrae in Dongyangosaurus indicates that a higher diversity of titanosauriformes occurred during the early Late Cretaceous in China.

Late Cretaceous Aquatic Angiosperms from Jiayin,Heilongjiang,Northeast China

Three taxa of Late Cretaceous aquatic angiosperms, Queruexia angulata （Lesq.） Krysht., Cobbania corrugata （Lesq.） Stockey et al. and Nelumbites cf. extenuinervis Upchurch et al. from Jiayin of Heilongjiang, NE China, are described in detail. Among them, Cobbania and Nelumbites from the Upper Cretaceous in China are reported for the first time. The aquatic angiosperm assemblage of Queruexia-Cobbania-Nelumbites appears to imply a seasonal, warm and moist environment in the Jiayin area during the Santonian-Campanian time.

Late Cretaceous Foraminiferal Faunas from the Saiqu“mélange”in Southern Tibet

As one of the mélanges in the southern side of the Yarlung-Zangbo suture zone, the Saiqu mélange in southern Tibet is important for understanding the evolution of the Neo-Tethys ocean. The age of the Saiqu mélange, however, has been debated due to the lack of reliable fossil evidence in matrix strata. Based on lithological similarities with platform strata in southern Tibet and limited fossils from exotic blocks, previous studies variously ascribed the Saiqu mélange to be Triassic in general, Late Triassic, or Late Cretaceous. Here we reported planktonic foraminiferal faunas from the matrix strata of the Saiqu mélange. The new fossils yield a Late Cretaceous age, which is so far the best age constraint for the mélange. Regional stratigraphic correlation indicates that the Cretaceous Oceanic Red Beds （CORBs） in Saiqu may be time equivalent to the CORBs of the Zongzhuo Formation in neighboring regions. Thus the Saiqu m^lange should be correlated to the Upper Cretaceous Zongzhuo Formation rather than the Triassic Xiukang Group, as previously suggested.

A New Somphospondylan Sauropod (Dinosauria, Titanosauriformes) from the Late Cretaceous of Ganzhou, Jiangxi Province of Southern China

A new somphospondylan sauropod （Dinosauria, Titanosauriformes）： Gannansaurus sinensis gen. et sp. nov. from the Late Cretaceous Nanxiong Formation of Ganzhou Basin, Jiangxi Province of southern China is erected based on one nearly complete dorsal vertebra and a mid-caudal vertebra. It is characterized by two centroprezygapophyseal lamina fossae; large, square-shaped concavity formed by centroprezygapophyseal lamina and dorsal margin of the centrum; large infraparapophyseal fossa; three openings present within the large lateral concavity, which occupy 65% length of the centrum; the posterior centroparapophyseal lamina （PCPL） and the anterior centroparapophyseal lamina （ACPL） weakly developed; the posterior centrodiapophyseal lamina （PCDL） separated by an infradiapophyseal fossa into two branches dorsally; parapophyseal and diapophyseal laminae cross to form ＂K＂ configuration. It shares some characters with the Early Cretaceous form-Euhelopus, indicating that it is more closely related to Euhelopus rather than to other titanosauriform sauropods. This means Gannansaurus may have a close phylogenetic relationship with Euhelopus.

A New Titanosaurian Sauropod from Late Cretaceous of Nei Mongol, China

A specimen collected from the Upper Cretaceous Erlian Formation of Nei Mongol （Inner Mongolia）, China, represents a new genus and species of titanosaurian sauropod. The new taxon is named and described on the basis of the holotype and the only known specimen, which comprises several dorsal, sacral, and caudal vertebrae, several dorsal ribs, one anterior chevron, and much of the pelvis. Diagnostic features of the new species include a thick ridge extending down from the postzygapophysis on the lateral surface of the neural arch of the posterior dorsal vertebrae, a transversely oriented accessory lamina present between the anterior centroparapophyseal limina and the lateral centraprezygapophyseal lamina of the posterior dorsal vertebrae, long, anteroventrally directed caudal rib that bears two distinctive fossae on its posterior margin on the anterior caudal vertebrae and a prominent vertical ridge above the pubic peduncle on the medial surface of the ilium, among others. The ilium is pneumatic, a feature not common among non-avian dinosaurs. The new taxon has an unusual combination of primitive and derived character states. Preliminary character analysis shows a complex character distribution within the Titanosauriformes. Recent titanosauriform discoveries suggest that a significant radiation occurred in Asia early in the titanosauriform evolution.

A Floating Astronomical Time Scale for the Early Late Cretaceous Continental Strata in the Songliao Basin, Northeastern China

A continuous terrestrial succession was recovered from the Songke-2(SK-2)borehole in the Songliao Basin,Northeastern China.This borehole provides a unique material for further research on the continental paleoclimate during Cretaceous greenhouse period,following a series of achievements of the Songke-1(SK-1)core.In this study,thorium(Th)logging data were chosen as a paleoclimate proxy to conduct a detailed cyclostratigraphic analysis.The Th series varies quasi-periodically;power spectra and evolutionary fast Fourier transformation(FFT)analysis reveal significant cycles in the Quantou(K2 q),Qingshankou(K2 qn),Yaojia(K2 y)and Nenjiang(K2 n)formations.The ratio of cycle wavelengths in these stratigraphic units is approximately 20:5:2:1,corresponding to long orbital eccentricity(405 kyr),short orbital eccentricity(100 kyr),obliquity(37 kyr),and precession cycles(22.5 kyr and 18.4 kyr).The durations of the K2 n,K2 y,K2 qn and K2 q are estimated as 6.97,1.83,5.30 and 4.52 Myr,respectively,based on the constructed^18.62 Myr"floating"astronomical time scale(ATS).Comparison of the durations between the SK-1 s and SK-2 boreholes exhibits a slight difference of 0.06 Myr and 0.459 Myr for K2 qn and K2 y.Nevertheless,our ATS of K2 n supports the chronostratigraphic frame constructed by the CA-ID-TIMS data of the SK-1 s borehole.This new"floating"ATS provides precise numerical ages for stratigraphic boundaries,biozones and geological events in the Songliao Basin,and can serve as a basis for correlation of strata and events between marine and terrestrial systems.

A New Sauropod Dinosaur from the Late Cretaceous Gaogou Formation of Nanyang,Henan Province

A new sauropod dinosaur Baotianmansaurus henanensis gen. et sp. nov. from the Cretaceous Gaogou Formation of Neixiang, Henan Province is erected. It is characterized by somphospondylous presacral vertebrae; a highly-developed lamina system on the dorsal vertebrae; transverse process supported by four laminae; and the dorsal portion of the anterior centroparapophyseal lamina is bifurcated, with a small branch extending to the ventral surface of the prezygapophysis. It represents a new titanosauriform sauropod.

Ostracod Biostratigraphy of the Late Cretaceous Qingshankou Formation in the Songliao Basin

An ostracod biostratigraphic study was performed on 425 samples from the composite geological section constructed by using cores taken from five selected wells drilled in the Late Cretaceous Qingshankou Formation in the Songliao basin. A total of 19 ostracod zones are established in the formation, of which 3 are newly established and 3 are revised. The 19 ostracod zones are described in detail. This study provides a basis for the detailed stratigraphic division and correlation of the Qingshankou Formation and the Gaotaizi oil reservoir in the oilfield in the Songliao basin.

Late Cretaceous Transpressional Fault System: A Case Study of the Yishu Fault Belt, Shandong Province, Eastern China

On the basis of field observations of the structures of three profiles from the Linshu region, deformation characteristics and the tectonic background of the Yishu fault belt in the Late Cretaceous–Early Cenozoic have been discussed in detail.Three structural profiles, whose deformations consist mainly of earlier transpressional faults and later normal faults, were developed for the Mengtuan Formation of the Lower Cretaceous Dasheng Group.Typical positive flower structures, duplex structures, and break-through faults were found in these profiles.On the basis of analyses of the structural deformation and previous geochronological studies, it was concluded that the earlier transpressional faults of the profiles were triggered by the sinistral transpression of the Yishu fault belt in the Late Cretaceous–Early Paleogene, and that the later normal faults, formed during the Late Paleogene–Neogene extension, truncated the earlier transpressional faults.With consideration of the tectonic evolution of the Tan-Lu fault belt and the different drift directions of the Pacific plate since the Cretaceous, we suggest that the major tectonic events of the Late Cretaceous–Neogene in eastern China were mainly controlled by the subduction of the Pacific plate.

A New Ootype of Dinosaur Egg (Faveoloolithidae： Duovallumoolithus shangdanensis oogen, et oosp. nov.) from the Late Cretaceous in the Shangdan Basin, Shaanxi Province, China

A new ootype collected from the Upper Cretaceous Lijiacun Formation in the Shangdan Basin,Shaanxi Province is described in this paper. Based on general external shape, size, eggshell thickness and honeycomb-like eggshell microstructure, eggs are referable to the oofamily Faveoloolithidae. Compared with other members of Faveoloolithidae, specimens described in this paper show special characteristics:adjacent pores are usually separated by two eggshell units between which often develop interspaces;columnar eggshell units are relatively closely arranged in radial view. According to these characteristics,we erect a new oogenus and a new oospecies: Duovallumoolithus shangdanensis oogen. et oosp. nov. The new discovery expands the diversity of Faveoloolithidae.

Petrogenesis of the late Cretaceous Turnagol intrusion in the eastern Pontides:Implications for magma genesis in the arc setting

A series of Cretaceous plutons is present in the eastern Pontides of northeastern Turkey. The Turnag61 intrusion is the least studied and, thus, the least understood plutons in the orogen. This intrusion consists of hornblende-biotite granodiorites emplaced at 78 Ma based on LA-ICP-MS U-Pb zircon dating. It is of sub- alkaline affinity, belongs to the medium- to high-K calc-alkaline series, and displays features typical of I- type granites. The rocks of the intrusion are enriched in large-ion lithophile elements and light rare earth- elements with negative Eu anomalies （EuJEu＊ = 0.69-0.82）, but are deficient in high-field-strength elements. They have a small range of （87Sr/S6Sr）i （0.7060 0.7063）, ENd （-2.6 to 3.1）, and 6180 （＋8.1 to ＋9.1） values. Their Pb isotopic ratios are 206pb/204pb = 18.63-18.65, ＇207Tpb/204pb = 15.62-15.63, and 208pb/204pb 38.53-38.55. The fractionation of plagioclase, hornblende, and Fe-Ti oxides had key functions in the evolution of the Turnag61 intrusion. The crystallization temperatures of the melts ranged from 758 to 885 ℃ as determined by zircon and apatite saturation thermometry. All these characteristics, combined with the low values of K20/Na20 and （Na20 ＋ K20）/（FeOt ＋ MgO ＋ TiO2）, as well as the high values of （CaO ＋ FeOt ＋ MgO ＋ TiO2）, suggest an origin by dehydration melting from a metabasaltic lower crustal source.

The Late Cretaceous source-to-sink system at the eastern margin of the Tibetan Plateau:Insights from the provenance of the Lanping Basin

The surface uplift of the Tibetan Plateau(TP)and its geomorphology evolution has triggered aridification of Asia's interior and drainage development at the eastern margin of the plateau.However,how the pre-Cenozoic early growth histories of the TP impact the drainage system and climate is poorly constrained.The Late Mesozoic Lacustrine evaporite-bearing basins on the eastern margin of the TP record significant information on the uplift of the source terranes,source-to-sink system development and climate change.In this study,we presented detrital zircon U-Pb ages from the Upper Cretaceous Yunlong Formation in the Lanping Basin,as well as Hf isotopic,petrographic,direct statistical,and multidimensional scaling analyses,and use them to characterize the provenance and reconstruct the drainage system.All of the samples have five major age peaks at 200-290 Ma,400-490 Ma,750-1000 Ma,1750-1950 Ma,and 2400-2600 Ma with mostly negativeε_(Hf)(t)values(81%).We infer the sediments are primarily derived from recycled sediments of the Songpan-Garze terrane,and partly from the Sichuan Basin and the Southern Qiangtang terrane,as well as the exposed magmatic rocks of the Yidun Arc and SongpanGarze terrane.The provenance features of the contemporaneous sediments from the Sichuan,Xichang,Chuxiong,and Simao basins indicate a complex hierarchical drainage pattern on the eastern margin of the TP during the Late Cretaceous.The hierarchical drainage system exhibits a complete gradational cycle of lake-basin types from overfilled freshwater Sichuan Basin through balanced fill saline Xichang Basin and underfilled hypersaline Chuxiong,Lanping,Simao,and Khorat Plateau basins from proximal to distal.The early growth of the TP primarily controlled the drainage and lake-basin evolution by not only causing the uplift and exhumation of the source areas and providing large amounts of clastic material to the proximal sub-drainage areas but also intensifying the aridity and deposition of evaporites.

Evolution of the Late Cretaceous Yongfeng-Chongren Basin in Jiangxi Province,southeast China: insights from sedimentary facies analysis and pebble counting

The Gan-Hang Belt in Southeast China is characterized by several igneous and siliciclastic basins associated with crustal extension during Late Mesozoic.The sedimentary evolution of the red basins is still poorly understood.In this study,sedimentary facies analysis and pebble counting were performed on outcrop sections of the Late Cretaceous Guifeng Group in the Yongfeng-Chongren Basin in central Jiangxi Province.Thirty-five conglomerate outcrops were chosen to measure pebble lithology,size,roundness,weathering degree and preferred orientation.Results show that gravels are mostly fine to coarse pebbles and comprise dominantly quartzites,metamorphic rocks,granitoids and sandstones.Rose diagrams based on imbricated pebbles indicate variable paleocurrent directions.Combining with typical sedimentary structures and vertical successions,we suggest that the Guifeng Group were deposited in alluvial fan,river and playa lake depositional systems.The proposed depositional model indicates that the Hekou Formation represents the start-up stage of the faulted basin,accompanied by sedimentation in alluvial fan and braided river environments.Then this basin turned into a stable expansion stage during the deposition of the Tangbian Formation.Except for minor coarse sediments at the basin margin,the other area iscovered with fine-grained sediments of lake and river environments.The Lianhe Formation,however,is once again featured by conglomerates,suggesting a probable tectonic event.Therefore,the study region possibly suffered two tectonic events represented by the conglomerates of the Hekou and Lianhe formations in the context of the crustal extension in Southeast China.