Early-diverging Titanosauriform(Dinosauria,Sauropoda)Teeth from the Lower Cretaceous Yixian Formation of Southeastern Inner Mongolia,Northeast China

Three eusauropod teeth(SDUST-V1064,PMOL-AD00176,PMOL-ADt0005)are reported from the Lower Cretaceous Yixian Formation of Ningcheng,southeastern Inner Mongolia,China.Two of them(SDUST-V1064,PMOL-AD00176)are assigned to early-diverging titanosauriforms in having slightly mesiodistal expansion at the base of the tooth crown,a slenderness index value>2.0 and<4.0,and D-shaped cross section.Furthermore,SDUST-V1064 and PMOL-AD00176 are referred as an Euhelopus-like titanosauriform on the basis of having a sub-circular boss on the lingual surface and an asymmetrical crown-root margin which slants apically,respectively.CT scan data of SDUST-V1064 reveals new dental information of early-diverging titanosauriforms,for example,the enamel on the labial side thicker than that on the lingual side,an enamel/dentine ratio of 0.26 and a boss present on the lingual side of the dentine of the crown.

Review of the Triassic Curvicubitidae(Insecta:Hemiptera),with Description of New Material from China

The Curvicubitidae is a Triassic cicada family with some taxa systematically debatable.Here a new curvicubitid species,Beaconiella tongchuanensis sp.nov.,is established from the Middle Triassic Tongchuan Entomofauna in NW China.Restudy of the two Australian species of Beaconiella Evans,1963(B.fennahi and B.multivenata)confirms that they are different species and first reveals the hindwing venation of B.multivenata.A detailed restudy of Curvicubitus triassicus Hong,1984 confirms the treatment of Curvicubitus as a junior synonym of Beaconiella.A key to all the six species of Beaconiella in Curvicubitidae is first given.Although reported from only three sites,the family Curvicubitidae potentially was globally distributed during the Middle-Late Triassic,implying that this family probably originated as early as the Early Triassic or even the Permian.

Fission Track Thermochronology Evidence for the Cretaceous and Paleogene Tectonic Event of Nyainrong Microcontinent, Tibet

Fission track dating was applied to analyze the 20 samples from Nyainrong microcontinent, and we obtained 20 apatite and 15 zircon fission track ages. The results show single population grain ages with a single mean age and associated central ages mainly ranging from 108±7Ma to 35±4Ma.Their mean track lengths are 12.2-13.9 μm with a single peak. Zircon fission track age range from 78±3 Ma to 117±4 Ma. The results represented the two tectonic uplift events in the study area, namely the Cretaceous and Paleogene periods. According to thermal history modeling results, uplifting rates of two tectonic events is 0.31-0.1 mm/a and 0.07-0.04 mm/a respectively. Combined with field condition and study results, it is suggested that the Cretaceous tectonic uplift event was related to the closure ocean basin caused by Qaingtang-Lhasa collision, and the Paleogene tectonic uplift event was related to the south to thrust system caused by Indo-Asian collision.

A New Species of Coniopteris moguqiensis sp. nov. from the Middle Jurassic Wanbao Formation in Eastern Inner Mongolia, China

In recent years, an increasing number of plant fossil leaves and petrified woods have been discovered from the Middle Jurassic Wanbao Formation in Moguqi Town of Inner Mongolia, NE China. Here, we describe a new species of Coniopteris moguqiensis sp. nov. preserved as a fragment with fertile and sterile pinnules. The sterile ultimate pinnules are elongate ovate with sphenopteriod type venation, and fertile pinnules are usually isolated, bipinnate at least with the sorus apical, elliptical, 1 mm in diameter;sporangia are almost globular, 100-150 μm in diameter, and the annulus is vertical. In situ spores are rounded-triangular in polar view, 25-30 μm in diameter with sides straight and slightly convex;trilete, laesurae are thin and slightly straight;the exine surface is usually psilate under the light microscope but finely reticuloid sculptured on the proximal view under a scanning electronic microscope. The fern genus Coniopteris usually suggests a warm and humid environment, which is consistent with the palaeoclimatic conditions of petrified wood and megafossil plants. The new discovery further supplements the floral composition of the Wanbao Formation, providing new material for understanding the evolutionary trend and classification of Coniopteris.

The Late Triassic I-Type Granites from the Longmu Co-Shuanghu Suture Zone in the interior of Tibetan Plateau, China： Petrogenesis and Implication for Slab Break-Off

The Jiangaidarina granitic mass(JM) is an important part of the magmatic belt in Longmu CoShuanghu Suture Zone(LSSZ) in the central Tibetan Plateau. An integrated research involving wholerock geochemistry, zircon LA-ICP-MS U-Pb ages and Hf isotopic compositions was carried out to define the timing, genesis and tectonic setting of the JM. Zircon LA-ICP-MS U-Pb ages have been obtained ranging from 210 to 215 Ma, rather than the Early Jurassic as previously thought. Fifteen granite samples contain hornblendes and show a negative correlation between POand SiO, indicating that the JM is an I-type granite. All the granites are enriched in LREE relative to HREE, with negative Eu anomalies(Eu/Eu*=0.56-0.81), and have similar trace elements patterns, with depletion of Ba, Nb, Sr and P. These suggest that the JM was fractionated, and this is also proved by the characteristic of negative correlations between oxide elements(TiO, MgO, FeOt, MnO, CaO) and SiO. Almost all ε(t) values of the granites are between-10.3 and-5.8, implying that the JM has a crustal source intimately related with the South Qiangtang Block(SQB), except for one(+10.2), showing a minor contribution from mantle source.Moreover, relatively low NaO/KO ratios(0.42-0.93) and high A/CNK values(0.91-1.50) reflect that the JM was predominately derived from the medium-high potassium basaltic crust, interacted with greywacke. Our new geochemical data and geochronological results imply that the Late Triassic magmas were generated in a post-collisional tectonic setting, probably caused by slab break-off of the Longmu Co-Shuanghu Tethyan Ocean(LSTO). This mechanism caused the asthenosphere upwelling, formed extension setting, offered an enormous amount of heat, and provided favorable conditions for emplacement of voluminous felsic magmas. Furthermore, the LSTO could be completely closed during the Middle Triassic, succeed by continental collision and later the slab broke off in the Late Triassic.

Petrogenesis of Early Permian Intrusive Rocks from Southeastern Inner Mongolia, China: Constraints on the Tectonic Framework of the Southeastern Central Asian Orogenic Belt

The late Paleozoic tectonic framework of the southeastern Central Asian Orogenic Belt is key to restricting the accretion orogeny between the Siberia Craton and the North China Craton. To clarify the framework, petrogenesis of early Permian intrusive rocks from southeastern Inner Mongolia was studied. Zircon U-Pb dating for bojite and syenogranite from Ar-Horqin indicate that they were emplaced at 288–285 Ma. Geochemical data reveal that the bojite is highly magnesian and low-K to middle-K calc-alkaline, with E-MORB-type REE and IAB-like trace element patterns. The syenogranite is a middle-K calc-alkaline fractionated A-type granite and shows oceanic-arc-like trace element patterns, with depleted Sr-Nd-Hf isotopes,(~(87)Sr/~(86)Sr)I = 0.7032–0.7042, ε_(Nd)(t) = +4.0 to +6.6 and zircon ε_(Hf)(t) = +11.14 to +14.99. This suggests that the bojite was derived from lithospheric mantle metasomatized by subducted slab melt, while the syenogranite originated from very juvenile arc-related lower crust. Usng data from coeval magmatic rocks from Linxi-Ar-Horqin, the Ar-Horqin intra-oceanic arc was reconstructed, i.e., initial transition in 290–280 Ma and mature after 278 Ma. Combined with regional geological and geophysical materials in southeastern Inner Mongolia, an early Permian tectonic framework as ‘one narrow ocean basin of the PAO', ‘two continental marginal arcs on its northern and southern' and ‘one intra-oceanic arc in its southern' is proposed.

Boundary of Cretaceous and Paleogene continental deposits in Zeya-Bureya Basin,Amur(Heilongjiang)River region

It was conducted the comparison of palynological assemblages of the Middle Tsagayan,Upper Tsagayan subformations,Furao and Wuyun formations from Zeya-Bureya Basin of Amur (Heilongjiang) River region with assemblages obtained from the marine deposits of Northeast Russia,Sakhalin,Kuril,and Hokkaido Islands,dated by ammonites,foraminifers and other invertebrates. Based on detail correlation,the geological age of the terrestrial beds was defined. The guide fossils are recognized Marsypiletes cretacea,Tricolpites variexi- nus,Aquilapollenites conatus,A. stelkii,A. rombicus,Integricorpus bellum,Pseudointegricorpus clarireticula- tus,Triprojectus amoenus,Orbiculapollis lucidus,Wodehouseia aspera,Quercoidites minor,which had last oc- currence in the late Maastrichtian. The Danian palynofloras usually are dominated by Triatriopollenites plicoides and T. confusus. The species Anacolosidites subtrudens,Aquilapollenites proceros,A. spinulosus have last occurrence in the Danian. The K-T (K-Pg) boundary in the terrestrial deposits is defined in the base of the Upper Tsagayan Subformation and the base of the lower part of the Wuyun Formation. The latter is represented by aleuropelite to fine-grained sandstones. The change of taxonomical composition of palynospectra in similar environments could be determined by real change of flora at the Mesozoic and Cenozoic boundary,but not by changes of lithological facies or depositional environment,generally.

Fossil biotas from Pakistan with focus on dinosaur distributions and discussion on paleobiogeographic evolution of Indo-Pak Peninsula

Recent geological and paleontological exploration in the Indus basin of Pakistan allowed the discoveries of numerous remains of non-marine reptiles( titanosaurian sauropod,abelisaurian and noasaurian theropod dinosaurs),and marine reptiles( crocodiles),flying reptiles( pterosaurs),marine and non-marine mammals,fishes,invertebrates,and plants,especially Pakistan is relatively rich in footprints / trackways in the Mesozoic.These vertebrates of Indo-Pakistan are very significant for paleobiogeographic study due to the present-day connection of this continent with Asia in Northern Hemisphere,whereas during past( Jurassic and pre-Jurassic) it was connected to the Gondwana. The Mesozoic vertebrates show close affinities with Gondwanan landmasses.The Cenozoic vertebrates show Eurasian affinity and migrated from Indo-Pak subcontinent to Eurasia or vice versa via Paleo Indus River systems along Western Indus Suture,after long journey of about 6 000 km the first collision of Indo-Pak subcontinent with Asia occurred at terminal Cretaceous.

A new species of Platanus from the Cenomanian(Upper Cretaceous) in eastern Heilongjiang, China

The stratigraphic division and sequence of the Upper Cretaceous sediments in eastern Heilongjiang Province,China,have been ambiguous and controversial,mainly due to a lack of biostratigraphically useful fossils and related radiometric dating.A new species of angiospermous fossil plant.Platanus heilongjiangensis sp.nov.,from Qitaihe in eastern Heilongjiang has been found in sediments conformably above which zircons from a rhyolitic tuff has been dated by U-Pb radiometric methods as 96.2±1.7 Ma.indicating that the Upper Houshigou Formation is of Cenomanian age.This discovery not only provides new data to improve our stratigraphic understanding of the Houshigou Formation,but also shows that Platanus flourished in the early Late Cretaceous floras of the region.This new study also indicates active volcanism taking place in the eastern Heilongjiang region during the Cenomanian of the Late Cretaceous.

Late Cretaceous biota and the Cretaceous-Paleogene(K--Pg)Boundary in Jiayin of Heilongjiang,China

An international cooperative study of the Late Cretaceous biota and non-marine strata including the Cretaceous-Paleogene(K--Pg) boundary in Jiayin near the Heilongjiang River,China during 2002-2010,is summarized in this paper. The strata includes the Upper Cretaceous Yong'ancun-,Taipinglinchang-,Yuliang-zi-,and Furao formations,and the Paleocence Wuyun Formation consisting of Baoshantou Member and a Coalbearing Member. Seven palynological assemblages from Santonian to Paleocene are recognized,which is used for definition of the K--Pg boundary. Through the palynological analysis of three drilled boreholes (XHY-2005,2006,2008) in Xiaoheyan of western Jiayin,the K--Pg boundary is defined within 20. 00-20. 05 m in the borehole XHY-2006 (as a standard boundary) which is just between the top of Furao Formation (late Maasterichtian) and the base of Baishantou Member (early Danian) . These new research results are supported by paleo- magnetic,geochemical and other analyses,also. On the other hand,the presence of eight taxa of Maasterichtian dinosaurs (mostly hadrosaurids) have been recognized by the authors; and two mega-plant assemblages from the Yong'ancun Fm (Santonian) to Taipinglinchang Fm (Campanian) are confirmed. These research a-chievements indicate that the Upper Cretaceous-Paleocene in Jiayin can be well correlated to the strata in the neighboring Zeya-Bureja basin,Russia. The K--Pg boundary definited in Jiayin is the first well documented non-marine K--Pg boundary in China. Also the related paleoclimate,paleoenvironment and the mass extinctions in this area during the Cretaceous-Paleocene transition are also discussed.

Logging curves characteristics and response mechanisms of basaltic facies and sub-facies: A case study from eastern sag of Liaohe depression, Northeast China

Based on five types of conventional logging curves including GR,RLLD,CNL,DEN and AC,and 39 core samples from 30 representative boreholes,the logging characteristics and lithofacies and sub-facies of the basaltic rocks were studied.Three basaltic facies and four sub-facies are recognized from the well logs,includ-ing volcanic conduit facies(post intrusive sub-facies),explosive facies,and effusive lava flow facies(tabular flow,compound flow and hyaloclastite sub-facies).The post intrusive,tabular flow and compound flow sub-facies logging curves are mainly controlled by the distribution of vesiculate zones and vesiculate content,which are characterized by four curves with good correlation.Post intrusive sub-facies are characterized by high RLLD,high DEN,with a micro-dentate logging curve pattern,abrupt contact relationships at the top and base.Tabular flow sub-facies are characterized by high RLLD,high DEN,with a bell-shaped log curve pattern,abrupt contact at the base and gradational contact at the top.Compound flow sub-facies are characterized by medium-low RLLD,with a micro-dentate or finger-like logging curve pattern,abrupt contact at the base and gradational contact at the top.Explosive facies and hyaloclastite sub-facies logging curves are mainly controlled by the distribution of the size and sorting of rock particles,which can be recognized by four kinds of logging curves with poor cor-relation.Explosive facies are characterized by low RLLD,medium-low CNL and low DEN,with a micro-dentate logging curve pattern.Hyaloclastite sub-facies are characterized by low RLLD,high CNL,low DEN and high AC,with a micro-dentate logging curve pattern.The present research is beneficial for the prediction of basaltic reser-voirs not only in the Liaohe depression but also in the other volcanic-sedimentary basins.

Fossil woods from the Upper Cretaceous to Paleocene of Heilongjang(Amur)River area of China and Russia

Fossil woods were collected from the Upper Cretaceous to Paleocene beds distributed around Heilong- jang （Amur） River area of China and Russia. A total of 43 specimens were collected from Baishantou, Long- gushan, and Yong＇ancun in Jiayin, China, and 85 specimens from Zeya-Bureya Basin lying southeast of Blagoveshchensk in Russia. Selected specimens were sectioned and studied anatomically. The source deposits of almost all identifiable specimens belong to the Upper Cretaceous （Campanian） Taipinglinchang Formation and the Paleocene Wuyun Formation in China, and the Paleocene Upper Tsagayan Formation in Russia. Al- though the results obtained are still far from complete, the taxonomic composition of the fossil woods show marked stratigraphic differences between the two horizons beyond the K/T boundary in China. There is also a strong similarity in wood flora between the Wuyun Formation of China and the Upper Tsagayan Formation of Russia. All identified specimens from the Taipinglinchang Formation are Xenoxylon latiporosum, This is one of the stratigraphically younger records of Xenoxylon, which is a conifer morphogenus of uncertain affinity most common in the Triassic to Early Cretaceous. Only one specimen with possible derivation from either the Wuyun or the Maastriehtian Furao Formation in China was identified as Taxodioxylon sp. The Wuyun Formation yielded both conifers and dicotyledonous woods. The conifers include Taxodioxylon sequoianum of the Taxodiaceae, and Protopiceoxylon amurense, which is attributable to the extant genera Keteleeria or Nothotsuga of the Pinaeeac, both are at present endemic to China. At least two morphotypes of dicotyledonous woods were recognized, with one identified as el. Hamamelidoxylon , and the other diffuse porous wood is characterized by numerous heterogeneous rays. From the Zeya-Buleya Basin of Russia, Taxodioxylon sequoianum and cf. Hamamelidoxylon sp. were identified from the Upper Tsagayan Formation. The similarity of wood composition in both Wuyun and Upper Tsagayan Formations support lithological as well as biostratigraphic correlations proposed for the two formations.

New Discovery of Nyssidium from the Yong’ancun Formation in Jiayin,China

Objective Follicular fruits in raceme infructescences with subparallel longitudinal ridges attached to the shoots were assigned to a widely used extinct genus of Nyssidium,which was suggested by Iljinskaja(1974)as the earliest appropriate generic name for this kind of fruits.

Comparison of Early Jurassic flora from South Primorye of Russia with its main coeval floras of China

The Early Jurassic flora,with over 42 species of 26 genera and documented in age by sandwiched marine beds,from the Lower Jurassic Schitukhe Formation of South Primorye,Russia,is further reported.The flora is dominated by cycadophytes,ferns and conifers,with some of ginkgoales and czekanowskiales,and characterized by occurrence of Cycadocarpidium,with very rare Coniopteris.A comparison of this flora with its coeval Early Jurassic floras of China is discussed.The Russian flora is considered as the early assemblage of Early Jurassic flora,and more similar to the Early Jurassic floras from the Shansonggang-and Yihe formations of Jilin,Beipiao Formation of Liaoning,and lower-middle Guanyintan Formation of Hunan in China.

Recent advance on study of Pleuromeia

Pleuromeia is an Early-Middle Triassic index lycopod plant,very significant for study of floral age,paleoecology and paleogeography.In recent years,the progresses in the study of Pleuromeia include the new taxon Pleuromeia shaolinii Zhang et Wang found from the Middle Triassic Lianjia flora in Benxi,China;and a new strobilus of Pleuromeia found from the Lower Triassic of Nevada,USA.Four species of Pleuromeia were selected by Mendelin et al.(2022)as the iconic taxa for four ages from the Lower to Middle Triassic in the world(including the Chinese species P.shaolinii),which is more significant for paleogeographic and evolutionary studies of Pleuromeia.

Recent advance in study of K-Pg boundary in Jiayin of Heilongjiang,China and its adjacent area

The non-marine Cretaceous-Paleogene boundary(KPgB)in Jiayin of Heilongjiang was first defined and reported in China by the authors research team in 2011.Thereafter the continuous research on the KPgB and its related Late Cretaceous biota in Jiayin has been made by the authors in 2012-2020.The achievements of the research are mainly reflected as follows:(1)a new drilling borehole with 60 m in depth carried out in the Xiaoheyan of Jiayin in 2016,supplemented new palynological evidence for the KPgB definition in 2011;(2)some radiometric dating newly made on the strata related to the KPgB in Jiayin and its neighboring Russian area,provided the supplemental evidence for the KPgB definition in Jiayin;(3)many new fossils found by the authors,represented by the angiosperms Dalembia and Nelumbo,refresh understanding the Late Cretaceous environment of Jiayin;and(4)the TEM method is applied in the study of pollen exine ultrastructure of Pseudointegricorpus,Wodehouseia,and Aquilapollenites,promoting the late Maastrichtian ecological study in Jiayin,related to the KPgB.

Early Cretaceous flora from coal-bearing strata of Markovsky Peninsula in South Primorye,Russia

The Early Cretaceous flora from the coal-bearing strata （Ussuri and Lipovtsy formations ） in the Markovsky peninsula of South Primorye, Far East Russia, is reported in some detail in this paper. The flora containing over 80 species of about 50 genera can be divided into two assemblages. The paleofloristie characteristics and the comparisons of this flora with its coeval floras from the adjacent region of the eastern Heilongjiang of Northeast China, indicate the flora and its coal-bearing strata of the Markovsky peninsula can be compared to those of the Chengzihe and Muling formations of the Jixi area of Heilongjiang, representing probably the late Barremian and Aptian age, respectively.

Two response patterns to negative environmental changes:Cases from Populus and Metasequoia

Traditionally,plant distribution is thought to be closely related to environmental factors.But recently,it is found that Populus,quite different from other plant taxa,adapted to negative environmental changes,and successfully migrated to different climate zones from its origin places of warm temperate zone.Conversely,Metasequoia is gradually tending to extinction from the Miocene to Quaternary.Based on above contrary cases,two response patterns of plant to negative environmental changes are proposed.One is active adaptation represented by Populus,the other is passive adaptation represented by Metasequoia.The plants of passive strategy characterized for desert prevention might be easily replaced by those of active strategy characterized for desert utilization.Fast growing plants,such as Populus with characteristics of drought and salt tolerance,wind and sand resistance,are selected in Tarim Basin in southern Xinjiang,China,as a good example of desert utilization in the construction of new highways and towns,not only serve as farmland shelterbelt in sandy area.In addition,Populus with high-altitude and cold adaptation has also been selected as an ideal tree planted in Tibet.Therefore,the idea of using Populus as one of the preferred pioneer trees to colonize Mars is proposed.

Glossopterids survived end-Permian mass extinction in North Hemisphere

Recently,more attention has been paid to Glossopteris,the most significant representative fossil of the Gondwanan Supercontinent in the Paleozoic.It has been regarded as an important clade of Angiophytes on the basis of its reproductive organ related to Angiosperms.Since Brongniart erected Glossopteris in 1928,reliable Glossopterids attached by fertile organs were only collected from the Permian Gondwanaland.Here,the authors found a new element of Glossoptetids,Sinoglossa sunii gen et sp.nov.,with attached female organs from the Middle Triassic Linjia Formation in Benxi,Northeast China.This demonstrates that Glossoptetids not only distributed in South Hemisphere,but also in North Hemisphere,and successfully survived the end-Permian mass extinction in North Hemisphere.The distinguished environment in Northeast China influenced by both warm and cold currents,probably resulted in the Paleozoic relic elements,such as Glossopterids associated with Lobatannularia successfully survived the end-Permian mass extinction.

Int’l Symposium on Cretaceous Biota and K-Pg boundary successfully held in Jiayin,China

“International Symposium on Cretaceous biota and the K-Pg boundary and the 2^nd Jiayin Forum on Fossil Protection”, co-hosted by the Key-Lab of Evolution of Past Life in Northeast Asia, Ministry of Natural Resources (EPLNEA, MNRC), Key-Lab for Evolution of Past Life and Environment in Northeast Asia, Ministry of Education, China (EPLENEA, MOEC), and Palaeontological Society of China (PSC), was successfully held in Jiayin County of Heilongjiang Province, China, during Aug.18-21, 2019. The symposium mainly aimed to introduce the recent advances on the Cretaceous-Paleogene (K-Pg) boundary made by the geoscientists from China and related countries, and to exchange the experiences and ideas on this topics, which is beneficial for the establishing the national standard of the K-Pg boundary in China based on the research projects “ Research on the K-Pg boundary of China” carried out by the EPLNEA, and MNRC.