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Middle Cretaceous pCO_2 Variation in Yumen, Gansu Province and its Response to the Climate Events

Acta Geologica Sinica(English Edition) 2018年第2期92卷 801-813页

作者： LEI Xiangtong du Zhen du baoxia ZHANG Mingzhen SUN Bainian School of Earth Sciences & Key Laboratory of Mineral Resources in Western China (Gansu Province) Lanzhou University State Key Laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences Key Laboratory of Petroleum Resources Gansu Province/Key Laboratory of Petroleum Resources Research Institute of Geology and Geophysics Chinese Academy of Sciences

The palaeo-atmospheric CO2 concentration （pCOz） variation in the Yumen, Gansu Province during the middle Cretaceous has been reconstructed using the newly established plant photosynthetic gas exchange mechanistic model, and the results show that the pCO2 values are in the range of about 550 -808 ppmv. The present pCO2 values are higher than the pCO2 results （531-641 ppmv） of the previous study according to the Recent standardization of the stomatal ratio method, and much lower than the pCO2 results （882-1060 ppmv） according to the Carboniferous standardization of the stomatal ratio method. The present pCOz variation is not only within the error range of GEOCARB II and GEOCARB Ill but also is similar to the reconstructed results based on the biochemistry and carbon isotope models. Besides, the present Brachyphyllum specimens were collected from four consecutive horizons of the upper Zhonggou Formation of the Hanxia Section, and the reconstructed pCO2 exhibits the reconstructed pCO2 exhibits a decline trend during the late Aptian to early Albian. This decline variation is probably associated with the Oceanic Anoxic Events （OAElb） and the Cold snap event. With the combination of pCO2 during the Albian to Cenomanian recovered by the plant photosynthetic gas exchange mechanistic model, the pCO2 showed a prominent increase during the late Aptian to early Cenominian, which indicates a response to the greenhouse warming during the middle Cretaceous. Therefore, the mechanical model of the plant photosynthetic gas exchange shows a relatively strong accuracy in the reconstruction of thepCO2 and can reflect a strong relation between the atmospheric CO2 concentrations and climatic events.

关键词： pCO2 greenhouse climate plant photosynthetic gas exchange mechanical model OAElb,Cold snap

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Altitudinal variation in Ginkgo leaf characters: Clues to paleoelevation reconstruction

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Science China Earth Sciences 2009年第12期52卷 2040-2046页

作者： XIE SanPing SUN BaiNian YAN DeFei du baoxia Key Laboratory of Western China’s Environmental Systems of the Ministry of Education Lanzhou UniversityLanzhou 730000China

After detailed studies of leaf area, leaf shape index, petiole length, stomatal density, stomatal index, and carbon isotope discrimination of Ginkgo biloba L., growing in Northwest China, the change trends of these parameters with an altitude gradient and their differences between sun and shade leaves were assessed. The results show that leaf area, petiole length, and stomatal parameters have no obvious linear relationship with altitude, but the carbon isotope discrimination shows a negative correlation with altitude, which has a potential to be an applicable paleo-altimeter. The results also suggest that the differences in stomatal density and stomatal index between sun and shade leaves had more influence on paleoelevation reconstruction than that in other parameters. Based on the linear and nonlinear correlations between carbon isotope discrimination and altitude, the paleoelevation evolution during the Middle Jurassic of the Yaojie Basin, Lanzhou in Gansu Province was estimated. The results show that the paleoelevation of the Yaojie Basin increased at first, and then decreased from the Aalenian to the early Bajocian and then to the late Bajocian in the Middle Jurassic.

关键词： altitude carbon isotope Ginkgo leaf area leaf shape index Middle Jurassic paleoelevation stomata

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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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Cuticles and Spores in Situ of Coniopteris hymenophylloides from the Middle Jurassic in Gansu, Northwestern China

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Acta Geologica Sinica(English Edition) 2018年第3期92卷 904-914页

作者： XIN Cunlin WANG Luhan du baoxia ZHANG Yamei WANG Jingjing College of Geography and Environmental Science Northwest Normal University College of Earth and Environmental Sciences Lanzhou University

Coniopteris was a ubiquitous plant of the Jurassic and Cretaceous periods and played an important role in the flora of the time. However, its anatomical structure is relatively poorly known. The specimens of Coniopteris hymenophylloides(Brongniart) Seward described here were collected from the Yaojie Formation in Gansu Province, northwestern China. The sterile fronds are characterized as being at least bipinnate with alternate arranged linear pinnae covered by thin cuticles. Fertile fronds are linear-lanceolate, with single sorus at the margin of each fertile pinnule. In situ spores are typically trilete, triangle to subcircular in polar view, cap-shaped in equatorial view, and 37 μm in average diameter. The trilete marking is straight and narrow, generally extends to 4/5 of the spore radius. The spore surface is smooth, and parts of the exine are granulated. The epidermal cells of cuticles are irregular in shape, approximately 40-60μm long and 10-20 μm wide. The elliptical stomatal complexes are paracytic,approximately 30 μm long and 19 μm wide,and irregularly distributed. On the basis of its epidermal structures and comparisons with extant ferns, we consider that Coniopteris displays combined features of the related extant genera.

关键词： Coniopteris hymenophylloides spore in situ cuticle Middle Jurassic Yaojie Formation Gansu China

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A new gnetalean macrofossil from the Lower Cretaceous of the Laiyang Basin, eastern China

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Plant Diversity 2024年第5期46卷 678-682页

作者： Peihong Jin Mingzhen Zhang baoxia du Jing Zhang Bainian Sun Key Laboratory of Petroleum Resources Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesGansu ProvinceLanzhou 730000China Key Laboratory Western China's Mineral Resources of Gansu Province Lanzhou UniversityLanzhou 730000China

Gnetophytes are a key group of plant for understanding seed plant phylogeny,partly because of their unique and elusive morphology,such as xylem with vessels,phloem with chaperones,reticular veins,and double fertilization(Endress,1996).In particular,the ovule bears a membranous integument,the upper part of which extends beyond the seed envelope to form a micropylar ***,gnetophytes occupy a unique evolutionary position in the phylogeny of seed plants and apparently represent a transition between angiosperms and other gymnosperms(Ran et al.,2018).Modern gnetophytes consist of only three families:Ephedraceae,Gnetaceae,and Welwitschiaceae,and each family contains only one ***(Ephedra L.)are the earliest diverging group of Gnetales,with a total of 70 extant species,and usually occur in cold and arid places in Asia,Europe,northern Africa,western North America and South America(Price,1996;Yang et al.,2017b).

关键词： phylogeny occupy Cretaceous

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An exceptionally well-preserved herbaceous eudicot from the Early Cretaceous(late Aptian–early Albian)of Northwest China

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National Science Review 2021年第12期8卷 46-54页

作者： baoxia du Mingzhen Zhang Bainian Sun Aijing Li Jing Zhang Defei Yan Sanping Xie Jingyu Wu Key Laboratory of Mineral Resources in Western China (Gansu Province) Lanzhou University Northwest Institute of Eco-Environment and Resources Chinese Academy of Sciences Key Laboratory of Petroleum and Resources Gansu Province

A fossil eudicot, Gansufructus saligna gen. et sp. nov., is reported from the Early Cretaceous(late Aptian–early Albian) of the Gansu Province, Northwest China, based on numerous well-preserved axes with attached leaves and infructescences. The leaves are alternate, short petiolate and linear-lanceolate with low rank pinnate to reticulate venation. The infructescences are loose panicles bearing fruits in different stages of maturity, each containing four partly free carpels borne in a whorled arrangement. Each carpel has three to five seeds borne along its ventral margin. The nature of the leaves and axes indicates a terrestrial,herbaceous habit. In general organization, Gansufructus is closely similar to the fruit-bearing axes of Sinocarpus decussatus from the Early Cretaceous Jehol Biota, as well as other more or less contemporaneous angiosperms from the Far East, which together provide evidence of diverse eudicot angiosperms of low stature colonizing areas close to environments of deposition.

关键词： eudicot Early Cretaceous Northwest China Jehol Biota Gansufructus paleoecology

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Fossil Taiwannia from the Lower Cretaceous Yixian Formation of western Liaoning, Northeast China and its phytogeography significance

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Research in Cold and Arid Regions 2018年第6期10卷 502-515页

作者： MingZhen Zhang baoxia du PeiHong Jin BaiNian Sun Key Laboratory of Petroleum Resources Gansu Province/Key Laboratory of Petroleum Resources Research Institute of Geology and Geophysics Chinese Academy of Sciences Key Laboratory of Mineral Resources in Western China (Gansu Province) and School of Earth Science Lanzhou University

Fossil Taiwania was discovered from the Lower Cretaceous Yixian Formation of Lingyuan City, western Liaoning Province, Northeast China. It is identified as a new species, Taiwania lingyuanensis sp. nov.. The present specimen is preserved as impressions with well defined leaf shoots system and reproductive structures. Leaves are dimorphic, spirally and imbricately arranged. They are scale-like on the main and cone-bearing branchlets, and subulate to falcate-subulate on the juvenile or sterile shoots. The seed cones are singly elliptic, ovate or elongate-ovate and terminally borne on ultimate shoots, bearing 22–24 scale-bracts complexes imbricately and helically arranged around the cone axis, the bracts are broadovate, rhomboidal or hexagonal with entire margins. Both the leafy shoots morphology and reproductive structures are similar to extant Taiwania. Furthermore, geological distribution and molecular biological evidences support that Taiwania is probably originated from the eastern Asia at least in the Early Cretaceous and widely distributed in the North Hemisphere thereafter.

关键词： Taiwannia Lower Cretaceous Yixian Formation leaves seed cones

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A New Species of Cupressinocladus from the Lower Cretaceous of Guyang Basin,Inner Mongolia,China and Cluster Analysis

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Acta Geologica Sinica(English Edition) 2017年第4期91卷 1200-1214页

作者： JIN Peihong MAO Teng DONG Junling WANG Zixi SUN Mingxuan XU Xiaohui du baoxia SUN Bainian School of Earth Sciences & Key Laboratory of Mineral Resources in Western China(Gansu Province) Lanzhou University School of Electrical Engineering and Computer Science Louisiana State University

Cupressinocladus Seward is a fossil genus of conifers and conifer fossils with reproductive organs are very rare. In general, it is difficult to understand the natural affinities with other conifers. In this paper, a new species, Cupressinocladus guyangensis P.H. Jin et B.N. Sun sp. nov., is reported based on branches with immature female cones from the Lower Cretaceous Guyang Formation of the Guyang Basin in Inner Mongolia, northern China. The foliage shoots are decussate. Leaves are decussate, imbricate, scale-like, weakly dimorphic, and bear longitudinal glands on the abaxial view. Stomata complexes are haplocheilic, monocyclic, irregularly arranged, and spread along the leaf margin. Immature female cones are subglobose with 6-8 cone scales, and three subglobose ovules arranged in a row at the base of the cone scales. Moreover, we performed cluster analysis using a statistics and machine learning toolbox for 23 fossils and extant species based on 16 morphological characters. The result implies that the new species bears a close resemblance to the extant Cupressusfunebris Endl. and might have nearest systematic affinities to it.

关键词： Cupressinocladus Immature female cone Lower Cretaceous Cluster analysis New species

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The late Pliocene species with ternate venation of Lauraceae from Tuantian flora, Tengchong, Yunnan Province, China

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科学通报 2013年第S1期58卷 193-199页

作者： DAO KeQun DONG Chong XU XiaoHui du baoxia WU JingYu XIE SanPing SUN BaiNian School of Earth Sciences and Key Laboratory of Mineral Resources in Western China Lanzhou University Lanzhou University Library Lanzhou University

A number of fossil leaves of the Lauraceae were collected from Tuantian flora of the late Pliocene strata in Yunnan, China. They have a whole leaf shape and well-preserved cuticles. In this paper, features of the architecture and epidermis of three species of the Lauraceae family with ternate venation are reported. Results of the comparison between the venation characteristics of Lauraceae fossils from four fossil floras in the world and those of extant Lauraceae in China suggest that the proportion of Lauraceae species with ternate venation is increasing. The proportion has risen from 10% in the Eocene to 12.5% in the late Pliocene in China, whereas the proportion in the modern era is 21%. Moreover, the proportion of Australian floras with ternate venation has rised from 8.3% to 10% between the Eocene and the Miocene. Because of the effect of the global drought during the Cenozoic era, we suggested that species with ternate venation in Lauraceae have become increasingly prevalent between the Eocene era and the present day in China. Data on Nerriga flora and Maarlake flora since the Eocene era in the Southern Hemisphere show the same trend. While features of the leaf architecture and epidermis of Lindera acuminatissima differ in details. They all have similar identification characteristics with regard to basal eucamptodromous venation, interior 2° present, minor 2° simple brochidodromous, anticlinal walls, no surface ornamentation, lip-like guard cells, outer stomatal ledge plain or dimness, and paracytic stomatal aperture. These differences are also present in extant species. Compared with Lindera tonkinensis, the nearest living relative(NLR) of L. acuminatissima shows that these differences are relevant to the growth, position, and development of leaves. Leaf-type classification statistics of L. acuminatissima indicate that when all fossil leaves are taken into consideration, A-type leaves account for 24%, B-type leaves make up 56%, and C-typy leaves account for 2

关键词： Lauraceae ternate venation fossil leaves Yunnan the late Pliocene

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Palynology of the Early Cretaceous Hanxia Section in the Jiuquan Basin,Northwest China:The discovery of diverse early angiosperm pollen and paleoclimatic significance

Palynology of the Early Cretaceous Hanxia Section in the Jiu...

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中国科学院地质与地球物理研究所2015年度（第15届）学术年会

作者： Mingzhen Zhang Liming Ji baoxia du Shuang Dai Xuewen Hou Key Laboratory of Petroleum Resources Gansu Province/Key Laboratory of Petroleum Resources ResearchInstitute of Geology and GeophysicsChinese Academy of Sciences Key Laboratory of Western China's Mineral Resources of Gansu Province MOE Key Laboratory of Western China's Environmental SystemsLanzhou University State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Chengdu University of Technology

The Lower Cretaceous deposits of the Jiuquan Basin(Northwestern China)located in central Asia are famous for the abundant and diverse fossil products with distinct characteristics of Jehol ***,few early angiosperm remains have been published in their *** study presents a palynomorph record from the recently reported fossil-bearing Zhonggou Formation of the Hanxia Section in the Jiuquan ***,we first discovered abundant and diverse angiosperm pollen with 16 taxa,which can be classified into four morphological types:tricolpate,polyaperturate,monosulcate and etrachotomocolpate *** palynomorph assemblages contain a large number of biostratigraphically significant palynomorphs,such as numerically abundant tricolpate and rare polyaperturate angiosperm pollen grains,which indicate an Early Albian age for the Zhonggou Formation of the Hanxia *** overall palynomorph assemblage is dominated by the Perinopollenites,followed by the Classopollis;bisaccate pollen indicate Taxodiaceae-dominant vegetation *** such,a relatively temperate and humid climatic condition is suggested for this ***,two palynomorph assemblages can be distinguished in a stratigraphically upward order with an obviously increasing Classopollis content,indicating a gradual aridification trend during the Early *** climatic change may affect the diversification of early angiosperms based on the correlation with the stratigraphic distribution of discovered angiosperm pollen.

关键词： Palynology Early angiosperm Albian Jiuquan Basin China

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