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Petrography,geochemistry and provenance of the sediments of the Early Cretaceous Yanguoxia Formation,Lanzhou-Minhe Basin,Northwest china

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Journal of Mountain science 2018年第9期15卷 2068-2088页

作者： DU Ding-ding MUGHAL Muhammad saleem ZHANG Cheng-jun school of earth sciences and mineral resources Lanzhou UniversityLanzhou 730000China key laboratory of western china's mineral resources of gansu province Lanzhou 730000China Institute of Geology University of Azad Jammu and KashmirMuzaffarabad 13100Pakistan

Lanzhou-Minhe Basin is situated on the middle Qilian orogenic belt. Yanguoxia Formation contains abundance of maroon siltstones, mudstones and red sandstones of the lake facies. These sedimentary rocks recorded the process of the tectonic uplift of Qilian Mountains during the Early Cretaceous. We discovered plentiful dinosaur footprints, worm burrows, bird footprints, worm tracks-trails, ripple marks and cross lamination in the Yanguoxia site. Integrated petrographic studies classified sandstones of Yanguoxia Formation as feldspathic litharenite. All plots in the QFL(Q or Qt, total quartz; F, feldspar; L, lithic grains) and Qm FLt(Qm, monocrystalline quartz; Lt, lithic grains plus polycrystalline quartz) diagrams fall in the recycled orogen provenance field and quartzose recycled field, respectively, implying the source occurred the tectonic activity. Furthermore, geochemical study indicates that the Yanguoxia standstone was formed in an unstable continental setting due to the northwards movement of Indian Plate triggered the collision between the Qilian fold belt and the Qinlingfold belt. These sediments were derived from a mixed source and then deposited in the Lanzhou-Minhe Basin. Most of the felsic components were derived from the granitoid rocks of the Qilian Mountains due to the rapid and intense uplift during the Early Cretaceous while the mafic components were contributed by the basic and ultrabasic rocks of the rapidly rising ophiolite in the Qilian Mountain area. Bivariant log-log plot of Qp/(F+L)(Qp, polycrystalline quartz) against Q/(F+L) shows that Yanguoxia Formation was deposited in the semihumid and semi-arid. Moreover, the pollen also exhibits that the environmental condition during the deposition of Yanguoxia Formation was warm and wet, which affirm such environment was benefit to dinosaur survival. Geochemical study also infers that the Yanguoxia Formation was deposited under the oxidizing condition in a shallow marine environment. The minerals id

关键词： Lanzhou-Minhe Basin YanguoxiaFormation Petrography Geochemistry Provenanceand weathering Teetonism and environment

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Fossil Liverworts from the Lower Cretaceous Huolinhe Formation in Inner Mongolia, china

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Acta Geologica sinica(English Edition) 2016年第3期90卷 838-846页

作者： LI Ruiyun WANG Xuelian JIN Peihong MA Fujun YAN Defei LIN Zhicheng sUN Bainian school of earth sciences&key laboratory of mineral resources in western china(gansu province) Lanzhou University Northwest University Museum Northwest University key laboratory of Economic stratigraphy and Palaeogeography Nanjing Institute of Geology and PalaeontologyCAS school of Petroleum Engineering Chongqing University of Science & Technology

A new genus and species, Rebouliothallus huolinhensis sp. nov., and two uncertain species, Ricciopsis sp. and Hepaticites sp., are described. The fossils were collected from the Lower Cretaceous Huolinhe Formation of Huolinhe Basin, northeastern china. The new genus Rebouliothallus was established in the Aytoniaceae family of Marchantiales. Rebouliothallus huolinhensis appears to be quite similar to species of the extant genus Reboulia Raddi. The species is characterized by the relatively large ventral scales. Ventral scales are large, imbricate and arranged in two rows on the ventral surface. Rhizoids are either pegged or smooth. Ricciopsis sp. is characterized by the rosette- forming thallus. Hepaticites sp. shows some similarities to liverworts. Of the forty-nine Early Cretaceous floras of china, only two floras, one from the Huolinhe basin, Inner Mongolia and the other from the Jixi Basin, Heilongjiang province, contain fossil liverworts. The rare fossil liverwort records in the Early Cretaceous floras of china may be the result of taphonomic bias.

关键词： Rebouliothallus Ricciopsis Hepaticites Early Cretaceous Huolinhe Formation

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Mid-Cretaceous Hothouse Climate and the Expansion of Early Angiosperms

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Acta Geologica sinica(English Edition) 2018年第5期92卷 2004-2025页

作者： ZHANG Mingzhen DAI shuang DU Baoxia JI Liming HU shusheng key laboratory of Petroleum resources Gansu Province/ Key Laboratory of Petroleum Resources Research Northwest Institute of Eco-Environment and Resources Chinese Academy of Sciences key laboratory of mineral resources in western china (gansu province) and school of earth science Lanzhou University Division of Paleobotany Peabody Museum of Natural History Yale University

The remarkable transition of early angiosperms from a small to a dominant group characterized the terrestrial ecosystem of the Cretaceous. This transition was instigated and promoted by environmental changes. Mid-Cretaceous is characterized by major geological events that affected the global environment. δ^18O, palaeothermometer TEX86, and other climatic indices from marine sediments suggest rapid temperature increase during mid-Cretaceous despite occasional short cooling events. simultaneously, terrestrial deposits in East Asia changed from coal-bearing to shale, then to red beds and evaporites. Plant assemblages and other paleoclimate indicators point to rapid aridification for midCretaceous terrestrial environments. In addition, the wildfires were frequently spread all over the earth by the numerous charcoal evidence during the Mid-Cretaceous. Thus, we speculate that the seasonally dry and hot conditions of mid-Cretaceous created a fiery hothouse world. Early angiosperms increased in abundance and diversity and evolved from a few aquatic species to terrestrial herbaceous and then to the diversified flora of today. Angiosperms showed rapid physiological evolution in vein density and leaf area that improved photosynthesis and water absorption. These ecophysiological changes made early angiosperms well adapted to the hot and dry environment in mid-Cretaceous. Moreover, these physiological changes facilitated the fire–angiosperm cycles in mid-Cretaceous that likely further stimulated the early angiosperm evolution.

关键词： Mid-Cretaceous hothouse wildfire early angiosperm diversification

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spatial-temporal Characteristics of Holocene Paleosols in the Chinese Loess Plateau and Paleoclimatic significance

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Chinese Geographical science 2022年第6期32卷 1110-1118页

作者： GUO Xuelian HE Lusheng ZHAO Guoyong WANG Weibin CAO Huairen WU Hao key laboratory of western china’s mineral resources of gansu province School of Earth SciencesLanzhou UniversityLanzhou 730000China College of Urban and Environmental science Xinyang Normal UniversityXinyang 464000China

The evolution of Holocene climate was investigated using grain size and magnetic susceptibility of the Holocene paleosols from Baicaoyuan(BCY),Xifeng(XF) and Linyou(LY) sections in the northwest,central and southern Chinese Loess Plateau(CLP).The results show that the Holocene in the B CY,XF and LY paleosol sections could be divided into three phases:during the early Holocene(11.8-10.5 kyr B.P.),increased magnetic susceptibility(χ) and frequency-dependent magnetic susceptibility(χ) and decreased median grain size(Md) indicate that the East Asian summer Monsoon(EAsM) has become more intense and the climate has changed from cold to *** the middle Holocene(10.5-5.0 kyr B.P.),the values of χ,χand 2-5 μm grain-size fraction(GT2/5) are higher and Md and 30-63 μm grain-size fraction(GT3 0/6 3) are the lowest,which reflect a warm and humid regional ***~8.0 kyr B.P.,there was a transient dry-cold climatic spike corresponding to a Heinrich Event,the cold event was likely due to the collapse of the Laurentide ice *** the late Holocene(5.0-0 kyr B.P.),χ and χvalues are the lowest,while Md and GT30/63 are high,as proxies of a weakened EAsM,when the dry-cold climate prevailed in the *** irradiance since 5.0 kyr *** have caused climatic cooling and ***,the increased main peak values and skewness from BCY,XF to LY sections show that the grain size became fine,the East Asian Winter Monsoon(EAWM) reduced,and climate was warmer and wetter from northwest to *** addition,Md can be used as alternative proxy for EAWM,while χis positive with the intensity of EAsM under semiarid climate conditions in CLP.

关键词： Holocene magnetic susceptibility grain size paleoclimate Chinese Loess Plateau(CLP)

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Late Paleozoic-Early Mesozoic tectonic evolution of the Paleo-Asian Ocean： geochronological and geochemical evidence from granitoids in the northern margin of Alxa, western china

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Frontiers of earth science 2018年第1期12卷 191-214页

作者： Xin sHA Jinrong WANG Wanfeng CHEN Zheng LIU Xinwei ZHAI Jinlong MA shuhua WANG school of earth sciences Gansu Key Laboratory of Mineral Resources in Western China Lanzhou University Lanzhou 730000 China state key laboratory for mineral Deposits Research Nanjing University Nanjing 210000 China

The Paleo-Asian Ocean （southern Mongolian Ocean） ophiolitic belts and massive granitoids are exposed in the Alxa block, in response to oceanic subduction processes. In this work, we report petrographic, geochem- ical, and zircon U-Pb age data of some granitoid intrusions from the northern Alxa. Zircon U-Pb dating for the quartz diorite, tonalite, monzogranite, and biotite granite yielded weighted mean 206pb/238U ages o f 302 ±9.2 Ma, 246.5±54.6 Ma, 235±4.4 Ma, and 229.5±5.6 Ma, respectively. The quartz diorites （-302 Ma） exhibit geochemical similarities to adakites, likely derived from partial melting of the initially subducted Chaganchulu back-arc oceanic slab. The tonalites （-246.5 Ma） display geochemical affinities of I-type granites. They were probably derived by fractional crystallization of the modified lithospheric mantle-derived basaltic magmas in a volcanic arc setting. The monzo- granites （-235 Ma） are characterized by low A1203, but high Y and Yb with notably negative Eu anomalies. In contrast, the biotite granites （-229.5 Ma） show high A1203 but low Y and Yb with steep HREE patterns and the absence of negative Eu anomalies. Elemental data suggested that the biotite granites were likely derived from a thickened lower crust, but the monzogranites originated from a thin crust. Our data suggested that the initial subduction of the Chaganchulu oceanic slab towards the Alxa block occurred at - 302 Ma. This subduction process continued to the Early Triassic （-246 Ma） and the basin was finally closed before the Middle Triassic （-235 Ma）. subsequently, the break-off of the subducted slab triggered asthenosphere upwelling （240-230 Ma）.

关键词： Paleo-Asian Ocean ALxa granite geochemistry

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An annually laminated stalagmite from the eastern Qinghai-Tibetan Plateau provides evidence of climate instability during the early MIs5e in the Asian summer monsoon

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science china earth sciences 2023年第5期66卷 1147-1164页

作者： Tao GAO Pingzhong ZHANG Hai CHENG Leilei ZHANG Xinhu LI Hongyu sHI Wei JIA Youfeng NING Hanying LI R.Lawrence EDWARDs key laboratory of mineral resources in western china(gansu province)and school of earth sciences Lanzhou UniversityLanzhou730000China Institute of Global Environmental Change Xi’an Jiaotong UniversityXi’an710054China Department of earth sciences University of MinnesotaMinneapolis55455USA

The Marine Isotope stage(MIs5e)is characterized by a warmer climate than that of the pre-industrial period,and serves as an analog for the Current Warm Period(CWP).However,uncertainties persist regarding its climatic ***,we retrieved a stalagmite(WXB075)from Wanxiang Cave in the eastern Qinghai-Tibetan Plateau,and employed abs-olute^(230)Th dating and relative annual layer data to establish a high-precision chronological framework for reconstructing the history of the Asian summer monsoon(AsM)and environmental evolution during early MIs5e with multiple *** findings indicate that the annually laminated stalagmite was formed during Cooling Event 27(C27).The deposition of WXB075 experienced a hiatus(~125.58 ka BP)due to a significant cooling event in the North Atlantic,which may be linked to the unstable climate in the Northern ***,the impact of meltwater discharge in high northern latitudes results in a two-phase evolution of the AsM,i.e.,an initial weaker stage followed by a gradual increase(with exception of deposition hiatus).The climatic instability of AsM is generally characterized by a quasi-60 year cycle that affects vegetation conditions,biological productivity,and karst hydroclimate ***,the increase in meltwater and decrease in temperature in the Northern Hemisphere have led to a weakened AsM and subsequent reduction in ***,vegetation degradation above the cave has occurred along with a slowdown of karst *** vegetation conditions,organic matter content,and wet/drought of the karst hydroclimate were affected by both the large-scale monsoon circulation and local environment during extreme weakening(strengthening)of the monsoon when high-frequency climatic events of AsM occurred.A comparison ofδ^(18)O records between early MIs5e and the past 2000 years reveals that the climate during early MIs5e differed significantly from that of CWP,Medieval Warm Period(MWP),and Dark Age Co

关键词： Eastern Qinghai-Tibetan Plateau Climate instability Wanxiang Cave stalagmite Asian summer monsoon Environmental response Deposition hiatus

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Formation of present desert landscape surrounding Jilantai salt Lake in northern china based on OsL dating

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Frontiers of earth science 2015年第3期9卷 497-508页

作者： Yuxin FAN Xiaolong CHEN Wenhao LIU Fu ZHANG Fan ZHANG school of earth sciences and key laboratory of mineral resources in western china of gansu province Lanzhou University Lanzhou 730000 China MOE key laboratory of western china's Environmental systems Collaborative Innovation Center for Arid Environments and Climate Change Lanzhou University Lanzhou 730000 China

The Jilantai salt Lake （JsL）, a lake of importance due to its salt production in china since the early Qing dynasty, is surrounded by sand dunes. Exploration of the development of these sand dunes will be helpful for identifying the forces underlying the desert landscape and for identifying a solution to protect the salt resources. Through field investigation, we found sand dunes overlying either lacustrine and bog deposits on the lake bed at a lower altitude or littoral sediments on the higher lakeshores. Optically stimulated Luminescence （OsL） dating results indicate that sands started to accumulate around the JsL as early as the early Holocene （around 11 ka）, while the rapid development of sand dunes occurred within the latest 0.1 ka. By comparison with climatic documents and human activities in adjacent regions, the initiation of sand accumulation around the JsL as early as the early Holocene is considered to be the result of low effective moisture in the Jilantai area. However, the rapid development of the sand dunes in the vast area surrounding the JsL was likely initiated by the intensified human activities which occurred within the latest 0.1 ka under warm and dry climatic conditions.

关键词： aeolian sand accumulation Jilantai salt Lake,OsL dating

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Biomolecular Preservation of Miocene Fossil Liquidambar from Tiantai,china and Clarkia,UsA:Implications for Palaeoenvironmental study

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Acta Geologica sinica(English Edition) 2015年第4期89卷 1076-1087页

作者： XIAO Liang YANG Hong HE Yuli HE Wenlong LI Xiangchuan GUO Junfeng HUI Kaixuan College of earth science and resources and Key Laboratory of Western Mineral Resources and Geological Engineering Ministry of EducationChang’an University laboratory of Terrestrial Environments Department of Science and TechnologyCollege of Arts and SciencesBryant University school of earth sciences and key laboratory of mineral resources in western china (gansu province) Lanzhou University College of Geology and Environment Xi’an University of Science and Technology

Biomolecular characteristics of fossil Liquidambar from the Miocene shengxian Formation, Tiantai, Zhejiang province in eastern china and Miocene Clarkia sediment, Idaho, U.s.A., are obtained by means of Pyrolysis-Gas chromatography-Mass spectrometry analysis （Py-GC-Ms）. Their modern equivalent （Liquidambarformosana） collected from Nanjing, eastern china, is also analyzed for comparison. The total ion chromatograms （TIC） of modern L. formosana leaves shows abundant pyrolysates of iignin, polysaccharide, aliphatic acid, and amino acid. However, only one polysaccharide molecule, i.e., levoglucosan, is retained in fossil Liquidambar leaves from the two Miocene sites with the Tiantai specimen possessing higher intensity. As expected, some lignin pyrolysates including benzene, phenol, guaiacol, vinylphenol and their derivatives, are detected in Miocene Tiantai L. miosinica. However, the lignin components with large molecular weight other than benzene and phenol compounds, are absent in Miocene Clarkia L. pachyphyllum. Abundant pristene and homologous series of n-alk-l-ene/n-alkane pairs with a long retention time are shown in pyrograms of both Tiantai and Clarkia fossils. Based upon our Py-GC-Ms data, the molecular preservation in these Liquidambar leaf samples can be ranked as the following （from high to low quality respectively）： modern sample 〉Tiantai sample 〉Clarkia sample. Vinyl phenol, an important compound, is present in modern and Tiantai Liquidambar leaves, while absent in Clarkia sample, implying that vinyl phenol may be sourced from lignin for Liquidambar leaves. Our data support the hypothesis of in situ polymerization for the origin of long-chain homologous series of n-alk-l-ene/n- alkane pairs as leaf alteration products. Our data have implications of the impact of leaf degradation toward biases for palaeoenvironmental reconstruction using stable carbon isotope of fossil plants, and suggest the importance of evaluating molecular preservation of fossil leaf t

关键词： Liquidambar Py-GC-Ms Miocene Biomolecules palaeoenvironment

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sub-Recent sexual Populations of Limnocythere inopinata Recorded for the First Time from>3500 m Altitude on the Tibetan Plateau

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Acta Geologica sinica(English Edition) 2015年第3期89卷 1041-1042页

作者： ZHANG Wanyi steffen MIsCHKE ZHANG Chengjun ZHANG Huirong WANG Peng school of resources and Environmental sciences Lanzhou University Institute of earth and Environmental science University of Potsdam Faculty of earth sciences University of Iceland school of earth sciences & key laboratory of mineral resources in western china(gansu province) Lanzhou University

The central and northwestern Tibetan Plateau region,also called＂Qiangtang Plateau＂（30°27＇25＂-35°39＇13＂N,83o41＇14＂-95°10＇46＂E）,is the highest and largest arcticalpine area of the earth covering approxima... 详细信息

关键词： sub-Recent sexual Populations of Limnocythere inopinata Recorded for the First Time from>3500 m Altitude on the Tibetan Plateau

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Detrital apatite fission track constraints on Cenozoic tectonic evolution of the northeastern Qinghai-Tibet Plateau, china： Evidence from Cenozoic strata in Lulehe section, Northern Qaidam Basin

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Journal of Mountain science 2018年第3期15卷 532-547页

作者： DU Ding-ding ZHANG Cheng-jun MUGHAL Muhammad saleem WANG Xiao-yu BLAIsE Dembele GAO Jun-ping MA Yuan LUO Xin-rong school of earth sciences and mineral resources Lanzhou University Lanzhou 730000 China key laboratory of western china's mineral resources of gansu Prouince Lanzhou 730000 China Institute of Geology University of Azad Jammu and Kashmir Muzaffarabad 13100 Pakistan

The Northern Qaidam Basin is located at the northeastern part of the Qinghai-Tibetan Plateau. It contains very thick Cenozoic terrestrial clastic sediments, which records the formation of the northern Qaidam Basin due to compressional deformation during the Indo-Asian collision. In this paper, we used detrital apatite fission-track thermochronology, including 4 sandstones and 2 conglomerates samples from the Lulehe section, to reveal the Cenozoic evolution of the northern Qaidam Basin. Fission-track dating indicated the source region of the Lulehe section has experiencedimportant cooling and uplifting in the Late Cretaceous(at ~85.1 Ma and ~65 Ma) and the Eocene(~52 Ma), respectively. The AFT age distribution on the section suggested that the provenance of Lulehe section sediments were mainly derived from the south Qilian shan(Qilian Mountains) and Altun shan(Altun Mountains), and two significantly provenance changes may occur at 43.4-46.1 Ma and ~37.8 Ma, respectively. The results may have strong constrains on the Cenozoic deformation and tectonic evolution of the northern Qaidam Basin and Qinghai-Tibet Plateau.

关键词： Northern Qaidam Basin Apatite Fission-Track Tectonic evolution Provenance analysis

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