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Geochemistry of a paleosol horizon at the base of the Sausar Group,central India： Implications on atmospheric conditions at the Archeane Paleoproterozoic boundary

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Geoscience Frontiers 2016年第5期7卷 759-773页

作者： Sarada P.Mohanty Sangitsarita Nanda Department of Applied Geology. Indian School of Mines Dhanbad 826004 India

A paleosol horizon is described from the contact of the Sausar Group（w2400 Ma） and its basement（Tirodi Gneiss; 〉2500 Ma） in Central India. Physical evidence of pedogenesis is marked by the development of stress corrosion cracks, soil peds, corestone weathering and nodular rocks. XRD and SEM-EDX data indicate the presence of siderite, ankerite, uraninite, chlorite, alumino-silicate minerals, ilmenite,rutile and magnetite, in addition to quartz, feldspar and mica. The chemical index of alteration, the plagioclase index of alteration, and the chemical index of weathering show an increasing trend from parent rock to the paleosol and indicate a moderate trend of weathering. The A-CN-K plot indicates loss of feldspars, enrichment in Al2O3 and formation of illite. Different major element ratios indicate baseloss through hydrolysis, clay formation, leaching of some elements, and more precipitation with good surface drainage. The paleosol is depleted in HREE in comparison to the parent rock indicating high fluid-rock interaction during weathering. The paleosol samples show flat Ce and Eu anomalies, low SREE, and high（La/Yb）N, indicative of a reducing environment of formation. Reducing condition can also be inferred from the concentration of elements such as V, Co, Cu, Pb, and Zn in the paleosol profile. Although enriched in Fe and Mg, the overall geochemical patterns of the paleosol indicate oxygen deficient conditions in the atmosphere and development by weathering and leaching processes associated with high precipitation and good surface drainage at the time of development of this paleosol during the Archeane Paleoproterozoic transition.

关键词： paleosol Anoxic weathering Great oxidation event Paleoproterozoic Sausar Group

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Molecular fossil and paleovegetation records of paleosol S4 and adjacent loess layers in the Luochuan loess section, NW China

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Science China Earth Sciences 2008年第3期51卷 321-330页

作者： ZHANG HuCai YANG MingSheng ZHANG WenXiang LEI GuoLiang CHANG FengQin PU Yang FAN HongFang Key Laboratory of Western China’s Environmental Systems Ministry of EducationCollege of Earth and Environment SciencesLanzhou UniversityLanzhou 730000China State Key Laboratory of Lake and Environment Sciences Nanjing Institute of Geography and LimnologyChinese Academy of SciencesNanjing 210008China

Using gas chromatography-mass spectrometry (GC-MS) technique, a series of biomarkers were identi- fied, including n-alkanes, n-alkane-2-ones, isoprenoid etc. from the loess-paleosol samples collected from the S4 and adjacent L5, L4 of the Luochuan loess section, Northwestern China. Based on these data, especially n-alkanes and high-resolution magnetic susceptibility and grain size data, the pa- leoenvironment and paleovegetation history during S4 was reconstructed. The CPI (Carbon Predomi- nance Index) and correlation between n-alkanes and magnetic susceptibility and grain size data dem- onstrated that the molecular fossils in paleosol and loess layers can reflect the vegetation condition during the loess-paleosol formation, if the allochthonous organic inputs could be excluded reasonably. The ACL (average chain length) index is correlated well with paleomagnetic susceptibility and grain size variations, displaying their good synchrony with warm and humid climate. However, it relatively lagged behind the paleomagnetic susceptibility and the grain size variations when the climate began to deteriorate. During the formation period of paleosol, the n-alkanes was dominated by C31 homologue, indicating that the primary organic input originated from herbs. Our study also demonstrated that the herbs were more flourish than wood plants in Loess Plateau, especially in the Luochuan area during the warm and humid phase, and there was no typical forest vegetation developed in the studied period.

关键词： paleoenvironment paleosol S4 Luochuan loess section biomarker paleovegetation

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Formation and Evolution of a paleosol across the Lower Silurian-Lower Permian Boundary in Zunyi District,Northern Guizhou,China and Its Paleoenvironment and Paleoclimate Implications

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Acta Geologica Sinica(English Edition) 2015年第6期89卷 2012-2029页

作者： XIONG Xiaohui XIAO Jiafei HU Ruizhong WANG Jian WANG Yi WANG Xinsong DENG Qi State Key Laboratory of Ore Deposit Geochemistry Institute of GeochemistryChinese Academy of Sciences Chengdu Institute of Geology and Mineral Resources Key Laboratory for Sedimentary Basin and Oil and Gas Resources Ministry of Land Resources Chinese Academy of Geological Sciences Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences

This paper presents a set of bulk geochemical and mineralogical data from a paleoweathering profile located in Zunyi District, Northern Guizhou, China. It was formed at the top of the Hanjiadian Formation of the Lower Silurian. A truncated, argillic, gleyed, kryptic paleospodosol is recognized in the paleoweathering profile. Ratios of immobile elements（Ti/Zr, Ti/Al） and their binary（e.g., Nb vs. Zr/TiO_2 and Th/Sc vs. Zr/Sc）, triangular diagrams（La-Th-Sc, Th-ScZr/10, Zr-Cr-Ga） reflect that the Gaojiayan paleosol is the product of in-situ weathering of gray-green silty mudstone of the underlying Hanjiadian Formation. Mass balance calculations indicate K enrichment and Na enrichment in the upper and lower portions of paleosol, respectively. These findings both are the results of transgression, which brings substantial concentrations of such elements as K, Na, and Sr. In particular, K enrichment is achieved by the illitization of kaolinite. The biological processes of terrestrial vascular plants also enhance K concentration, especially at the top of the paleosol. Na enrichment is a consequence of albitization and/or adsorption by clay minerals through cation exchange. The mass distributions and relative mass changes of rare earth elements（REEs） in the studied profile display characteristics of vertical zonation. Three peaks in total REEs content are observed, indicating two paleoclimatic or paleoenvironmental changes. Mineralogical characteristics indicate that the paleoclimate changed first from warm and humid to cold and dry and later, to dry and lightly warmer. The corresponding soil environment varies from weakly acidic to strongly alkaline and later, to weakly acidic. Mass translocation characteristics of REEs and several transition metals suggest that the Gaojiayan paleosol may have undergone top erosion.

关键词： paleosol paleoclimate paleoenvironment Lower Silurian-Lower Permian NorthernGuizhou

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An isotopic study of the S1 paleosol carbonates from the central Loess Plateau of North China

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Chinese Science Bulletin 1996年第18期41卷 1542-1545页

作者：陈骏安芷生王洪涛高燕 Department of Earth Sciences Nanjing University Nanjing 210008 China Xi'an Laboratory of Loess and Quatrnary Geology Chinese Academy of SciencesXi'an 710061China

The loess-paleosol sequence in the central Loess Plateau of China is produced under arid to sub-humid climatic conditions and contains abundant carbonates. These carbonates could be partly detrital derived from provenance by aerosol and partly authigenic precipitated during weathering and pedogenesis after deposition of the aerosol. Some previous studies have examined oxygen and carbon isotopic compositions of the carbonates by means of whole rock samples containing various amounts of detrital carbonates.This study separates authigenic carbonate from detrital one and only examines the former in order to investigate isotopic composition of the pedogenic carbonate and to discuss its relationships to the Asian paleomonsoon probably existing during the last interglacial time.

关键词： paleosol paleomonsoon paleoclimate stable isotopes of soil carbonate.

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A tropical paleosol at high elevation in the Yulong Mountains and its implication on the uplift of the Tibetan Plateau

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Chinese Science Bulletin 2001年第1期46卷 69-73页

作者： Zhengtang Guo Xiaofeng Yao Xitao Zhao Lanying Wei Chinese Acad Sci Inst Geol & Geophys Beijing 100029 Peoples R China

A paleosol dated for about 500-700 kaBP and developed on a glacial deposit at -3 000 in a.s.l. in the Yulong Mountains is studied using soil chemical, morphological and mineralogical methods. The analytical results indicate that this soil was formed under tropical and humid conditions and can be classified as red soil, which cannot be formed in the present alpine environment at the studied site. This implies that the southeast margin of the Tibetan Plateau has experienced intense uplift since the formation of the paleosol. According to the necessary conditions for the formation of the modern red soil in China, we estimate that the

关键词： Yulong Mountains paleosol paleoenvironment uplift of the Tibetan Plateau.

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Palynomorphs in the first paleosol layer in the Yangtze Delta and their paleoenvi-ronmental implication

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Chinese Science Bulletin 2002年第21期47卷 1837-1841页

作者： WU Guoxuan QIN Jungan DENG Bing LI Congxian Key Laboratory of Marine Geology Ministry of EducationTongji UniversityShanghai 200092China

The relatively abundant palynomorphs were recovered from the samples of the first paleosol layer of core CY in Shanghai for the first time. A total of 55 genera and families of spore, pollen and phytoplankton were identified. According to the characteristics of the palynological assemblages, the depositional conditions in the development period of the paleosols were discussed and the microfossil evidence to study the origin of the paleosols in the Yangtze Delta area was provided as well. The research results show that paleosols should be freshwater deposits. The palynological assemblage sequence in the first paleosol layer reveals fluctuations of freshwater palynomorphs, mainly Concentricystis, and terricolous herbs pollen, reflecting the alternations of deposition and exposure in the development period of the paleosols. Concentricystis developed prosperously in the period of flood, while terricolous herbs grew on the emerged land in the period of exposure. The variations in the palynological

关键词： Yangtze Delta paleosol layer sporopollen phytoplankton paleoenvironment.

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Soil evolution along an alluvial-loess transect in the Herat Plain,western Afghanistan

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Journal of Arid Land 2022年第11期14卷 1317-1330页

作者： Farsila MAHMOUDIAN Alireza KARIMI Omid BAYAT Department of Soil Science Faculty of AgricultureHerat UniversityHerat 3001-272806Afghanistan Department of Soil Science Faculty of AgricultureFerdowsi University of MashhadMashhad ***Iran

Afghanistan is located in the Eurasian loess belt,however,there is little information on the soils in the area.Loess has covered the Herat Plain in western Herat City,Afghanistan.Despite the diversity of landform and parent material,there is no information on the soil and landform evolution in this area.The objectives of this study were to identify the soils along a transect of different landforms in the Herat Plain and determine the role of geomorphic processes on the soil and landform evolution.Five pedons from an alluvial fan,the depression between alluvial fan and piedmont plain,saline and non-saline piedmont plains,and the flood plain of the Hariroud River,were sampled.Then,the physical-chemical properties,mineralogy,and micromorphology of the samples were determined.Results showed that the soil parent material in the piedmont plain is loess,whereas,in the flood plain it is a combination of loess and river alluvial sediments.Calcification,lessivage,salinization,and gleization are the most important pedogenic processes.The calcification and lessivage appear to be the result of a wetter climate during the late Quaternary,whereas the present topography causes the gleization and salinization.Clay coatings on carbonate nodules and iron nodules are abundant pedofeatures in the Btk(argillic-calcic)horizon.Iron oxides nodules are common in the soils of the flood plain.The formation of palygorskite in both alluvial-and loess-derived soils implies the onset of aridity and the trend of increase in environmental aridity in the region.It seems that after the formation of a well developed paleosol on the alluvial fan in a more humid climate in the past,the piedmont plain has been covered by loess deposits,and the calcification,gleization,and salinization cause the formation of weakly developed surficial soils.This study highlights the role of the late Quaternary climatic changes on the evolution of landforms and soils in western Afghanistan.

关键词： alluvial fan loess-derived soils paleosol gleization Hariroud River

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Climatic Fluctuation of Marine Isotope Stage 9: A Case Study in the Southern Margin of the Chinese Loess Plateau

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地球科学学刊:英文版 2023年第5期34卷 1556-1566页

作者： Tieniu Wu Antai Cheng Henry Lin Hailin Zhang Yi Jie Key Laboratory for Geographical Process Analysis&Simulation Hubei ProvinceCentral China Normal UniversityWuhan 430079China Department of Ecosystem Science and Management The Pennsylvania State UniversityUniversity ParkPA 16802U.S.A. College of Urban and Environmental Sciences Central China Normal UniversityWuhan 430079China

Marine Isotope Stages(MIS) 9 has been proposed as an analog for the present warm period. However, detailed studies of this geological time period are rare in loess-paleosol sequence. In the Chinese Loess Plateau(CLP), the corresponding stratum is the third paleosol layer(S3). Here, we report the terrestrial reconstruction of climatic fluctuations during MIS 9 by analyzing the paleo-climate indexes of S3 with high sampling density. Our results showed that:(1) During the period of MIS 9, the main climatic sub-cycle was 29 ka;(2) MIS 9 could be divided into five sections, MIS 9a, 9b, 9c, 9d, and 9e. Among them, MIS 9a, 9c, and 9e were warm stages, while MIS 9b and 9d were cool intervals;and 3) There were also three swift warm-wet events and one cool-dry event, which occurred around 332 –331, 324–323, 311–310, and 331–329 ka BP, respectively. The overall trend of paleo-climate fluctuation correlated approximately with SPECMAP, LR04 stack and Iberian margin deep-sea cores. This study suggested that the paleosol records in the southern margin of the CLP have global significance and contain more detailed climatic signals than marine deposits.

关键词： MIS 9 climatic fluctuation paleosol S3 Chinese Loess Plateau environmental geology

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paleosol evolution and environmental change in the Huang-Huai-Hai Plain, China

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Chinese Science Bulletin 1999年第S1期44卷 255-258页

作者： LIU Liangwu GONG Zitong Institute of Soil Science. Academia Sinica P. O. Box 821. Nanjing 210008, P. R China

paleosols in the Huang-Huai-Hai Plain occur mainly in the Huaibei, Xuhuai, Yischuheand Jiaolai areas. They result from 3 sedimentation-soil formation cycles since the LatePleistocene. Each cycle left calcareous concretions, a dark soil horizon, and a topsoil horizonand/or a stratified soil horizon all derived from loess. This paper examines the composition of theconcretions, compares this with that of the enclosing soil horizons, and draws some environmentalconclusions. Three types occur: embryonic calcareous concretions, mature calcareous concretions,and calcareous hardpans （petrocalcic horizons）. The embryonic concretions formed during themid-Holocene （6780±130 yr. B.P.）, mature calcareous concretions during the late-Pleistocene（weighted average of 31 samples = 15670±370 yr. B.P.）, and calcareous hardpans （petrocalcichorizons） from 16 to 40 ka B.P. The calcium carbonate content increases from 412 g/kg in theembryonic concretions, to 551 g/kg in the mature concretions, and to 691 g/kg in the hardpan,whereas contents of SiO2, Al2O3 and TiO2 decrease accordingly. Spore pollen analysis shows thatthe late-Pleistocene there was dry and cool, whereas the mid-Holocene was warm and humid andlakes were more extensive than today.

关键词： paleosol evolution radiocarbon dating sedimentation-soil formation cycles changing environment

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Contrasting magnetic properties from two loess/paleosol sections in Gansu Province, west China

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Chinese Science Bulletin 1999年第S1期44卷 181-188页

作者： Toshiaki Mishima Masayuki Torii H.Fukusawa K.Oi T.Sasaki Y.Ono Division of Earth and Planetary Sciences Kyoto University Kyoto 606-8502 Japan Present address: Graduate School of Science and Technology Kobe University Kobe 657-8501 Japan. Division of Earth and Planetary Sciences Kyoto University Kyoto 606-8502 Japan Present address: Graduate School of Science and Technology Kobe University Kobe 657-8501 Japan. Present address: Faculty of Informatics Okayama University of Science Okayama 700-0005 Japan. Department of Geography Tokyo Metropolitan University Hachioji 192-0364 Japan Graduate School of Environmental Earth Science Hokkaido University Sapporo 060-0810 Japan

We made comparison of magnetic property between two loess/paleosol sediments from theBeiyuan section, Linxia and the Shajinping section, Lanzhou. The two sections apart only 100 km inNE-SW direction. At the Beiyuan section, enhancement of the low-field magnetic susceptibility, ARMsusceptibility and SIRM are observed in paleosols. The positive correlations among these threeparameters suggest the presence of two magnetic components, i.e. the background component and theenhanced component. The unblocking curves of low-temperature IRM give strong evidence for the ideaof the two components. On the contrary, the magnetic parameters are almost constant throughout theShajinping section. The enhanced component is not found in the Shajinping section. The magneticproperties of the background component are indistinguishable between the two sections. Contrastingmagnetic properties imply the difference of soil formation process between the two sections.

关键词： loess paleosol magnetic properties environmental magnetism

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