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Tillage pedogenesis of Purple Soils in Southwestern China

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Journal of Mountain Science 2009年第2期6卷 205-210页

作者： HE Xiubin BAO Yuhai NAN Hongwei XIONG Donghong WANG Li LIU Yanfeng ZHAO Jingbo Institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu 610041 China Graduate School of the Chinese Academy of Sciences Beijing 100049 China Shaanxi Normal University Xi'an 710062 China

Land cultivation and tillage process, and their consequent impacts on soil erosion, have been criticized as the main cause of degradation of land or soil quality. However, purple soils, classified as Regosols in FAO Taxonomy or Entisols in USDA Taxonomy, are formed from purple rocks of the Trias- Cretaceous system, have been developed or at least accelerated the development due to continual tillage operation, especially digging and ridging. The present study took micromorphological investigation on the sedimentary rocks and the soils under different operations of tillage. Results show that the purple rock of Feixiangguan Formation of the Trias system （Tlf） is the easiest to physical weathering and the most fertile soil material enriched in nutrients, and it has been, therefore, mostly cultivated and intensively tilled around the year. It has the fastest soil formation rate. Soil formation rate in the cropland with conventional tillage is higher than that in the forestiand and the grassland. It implies that the artificial brokenness and tillage disturbance play a great role in physical weathering and initiating soil formation processes.

关键词： Tillage impact pedogenesis purple soil micromorphology southwestern China

pedogenesis affecting the Matuyama-Brunhes polarity transition recorded in Chinese loess?

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Pedogenesis affecting the Matuyama-Brunhes polarity transiti...

中国科学院地质与地球物理研究所2001学术年会

作者： GUO Bin~1,ZHU Rixiang~1,Florindo Fabio~2, PAN Yongxin~1 & YUE Leping~3 1.Institute of Geology and Geophysics,Chinese Academy of Sciences, Beijing 100101,China 2.Istituto Nazionale di Geofisica,Rome,Italy 3.Department of Geology,Northwest University,Xi’an 710029,China

A detailed record of the Matuyama-Brimhes (M-B) transition has been obtained from the loess unit 8(L8) at Duanjiapo(34.2°N,109.2°E),Shannxi Province of China. An investigation of the rock magnetic properties using hysteresis loops,thermomagnetic analyses identifies pseudo-single domain magnetite as the main carrier of the remanence, with a small contribution from maghemite and hematite. The paleo-direction records obtained reveal:(i) The M-B transition was recorded in the middle and lower part of L8,and comprises of five fast reversals.(ii) The duration of the M-B polarity transition related to the directional change is about 4800 a.(iii) The virtual geomagnetic pole(VGP) path during the transition is confined over Africa,peaked 90°away from the sampling site,in contrast with the results obtained from the Weinan loess *** different VGPs are probably attributed to the pedogenesis.

关键词： M-B polarity transition VGP path pedogenesis loess

Environmental magnetic study of a Xeralf chronosequence in northwestern Spain:Indications for pedogenesis

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Environmental magnetic study of a Xeralf chronosequence in n...

中国科学院地质与地球物理研究所第十届(2010年度)学术年会

作者： José Torrent Vidal Barrón Departamento de Ciencias y Recursos Agricolas y Forestales Universidad de CordobaEdificio C4Campus de Rabanales14071 CordobaSpain

Magnetic enhancement of A and B horizons during soil development is a common *** better understand the exact mechanism for the magnetic enhancement,especially the mineral transformation pathways,systematic rock magnetic studies were conducted on a Xeralf chronosequence in northwestern Spain.A positive correlation was found between the average grain size and the concentration of pedogenic maghemite particles with the exception of some A horizons,in which multiple factors seem to influence the nature and concentration of neoformed *** is argued that the interaction between the positively charged iron oxides and the anionic ligands present in the solution of these acidic soils plays an important role in this *** time trends of the average grain size of pedogenic ferrimagnets and the strong correlation between the concentrations of hematite and maghemite in the magnetically enhanced horizons (A and B)are consistent with the hypothesis of a gradual formation of maghemite(later converted into hematite)via a precursor(most likely ferrihydrite).Therefore,this study provides strong evidence for the dynamic evolution of magnetic minerals upon pedogenesis.

关键词： Soil magnetism Chronosequence pedogenesis

Particle size separation and evidence for pedogenesis in samples from the Chinese Loess Plateau spanning the past 22 m.y.

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Particle size separation and evidence for pedogenesis in sam...

中国科学院地质与地球物理研究所2008学术年会

作者： Frank Oldfield Jan Bloemendal Department of Geography University of LiverpoolLiverpool L69 7ZTUK

A comparison between particle size distributions determined by laser diffraction and the pipette method confirms previous studies that point to a variable underestimate of the clay fraction using laser diffraction,relative to the values obtained by pipette *** order to yield four particle-sized fractions(8μm) for further analysis, the pipette method was used on loess and paleosol samples from sites on the Chinese Loess Plateau spanning the past 22 *** all cases,a subsidiary mode in the8μm fraction provides a basis for evaluating the relative contributions of pedogenic and detrital *** using acetic rather than hydrochloric acid for carbonate removal results in no significant loss of ferrimagnetic minerals and allows magnetic characterization of the separate fractions. This confirms the isolation of almost all the finest,pedogenic ferrimagnetic grains in the clay fraction and their negligible contribution to the magnetic properties of the coarse fractions in all the samples from early Miocene time *** similar conclusions may be drawn from previous studies of late Pleistocene samples from the east-central and extreme western parts of the Chinese Loess Plateau,we conclude that this approach provides a basis for separately characterizing eolian deposition and pedogenesis throughout the region and for the whole time span of loess accumulation.

关键词： loess pedogenesis granulometry pipette analysis magnetic properties

Characterizing and quantifying iron oxides in Chinese loess/paleosols:Implications for pedogenesis

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Characterizing and quantifying iron oxides in Chinese loess/...

中国科学院地质与地球物理研究所2013年度（第13届）学术年会

作者： Pengxiang Hu Qingsong Liu José Torrent Vidal Barron Chunsheng Jin State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of Sciences Departamento de Agronomfa Universidad de CordobaEdificio C4Campus de Rabanales14071 CordobaSpain Division of Cenozoic Geology and Environment Institute of Geology and GeophysicsChinese Academy of Sciences

To accurately decode the paleoclimatic and paleoenvironmental significance of magnetic properties in Chinese loess/paleosols,neoformation of magnetic iron oxides via pedogenesis as well as the relationship between ferrimagnetic(maghemite and magnetite)and antiferromagnetic minerals(hematite and goethite)of both detrital and pedogenic origins should be well *** resolve this problem, magnetic iron oxides from a contiguous loess-paleosol sequence(lower part of the loess unit L1,paleosol unit S1,and the upper part of L2)at Luochuan,Center of the Chinese Loess Plateau,were well characterized and quantified by using an integrated approach including chemical dissolution,diffuse reflectance spectroscopy and rock magnetism *** showed that these magnetic minerals have distinct coercivity and dissolution behavior,which is highly grain *** specifically, the paleosol is enriched with nano-sized pedogenic hematites with a medium coercivity of～130 mT, which are also preferentially dissolved in a weak reductive *** contrast,the coarse-grained micro-sized detrital hematites with a medium coercivity of～1T are dominant in loess,In addition,these coarse-grained detrital hematites are more stoichiometric than their pedogenic counterparts as evidenced by the higher band position on the diffuse reflectance *** can be well distinguished from hematite by its higher coercivity(4-7T)at low temperature(10K).The consistent dissolution behavior of goethite for both loess and paleosol samples in citrate-bicarbonate-dithionite solution indicates that goethite could be less relevant to the pedogenic *** reductive dissolution of pedogenic maghemite lags the dissolution of pedogenic hematite and fine-grained goethite,which suggests that average grain size of pedogenic maghemite is relatively larger than those of pedogenic hematite and fine-grained *** magnetite is hard to dissolve and～50%of its initial remanence su

关键词： pedogenesis magnetic iron oxides dissolution rock magnetism diffuse reflectance spectroscopy Chinese loess

Rock-magnetic characteristics and mechanisms of the Titel loess-paleosol sequence in northern Serbia since late Middle Pleistocene

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Science China Earth Sciences 2022年第3期65卷 503-517页

作者： Zhi LIU Xiuming LIU Slobodan B.MARKOVIC Bin LU Ruina HE College of Geography and Environment Baoji University of Arts and SciencesBaoji 721013China Key Laboratory of Disaster Monitoring and Mechanism Simulation of Shaanxi Province Baoji 721013China School of Geographical Sciences Fujian Normal UniversityFuzhou 350007China Department of Earth and Environmental Sciences Macquarie UniversitySydneyNSW 2109Australia Chair of Physical Geography Faculty of SciencesUniversity of Novi SadTrg Dositeja Obradovica 321000 Novi SadSerbia

The changing pattern of magnetic characteristics in eastern European loess deposits is the most similar across the world to that of the Chinese Loess Plateau,both of which are dominated by the strength of *** a systematical study to the rock magnetism of eastern European loess is not only helpful for understanding the paleoclimatic information preserved by themselves,but also beneficial for promoting the cognition of the pedogenic mechanism in loess *** this study,a detailed rock-magnetic analysis of seventy loess/paleosol samples,taken from the Titel Loess Plateau in northern Serbia,is carried out for a better understanding of the magnetic records since late Middle *** results provide us some ***,the magnetic susceptibility values of the paleosols in the Titel loess-paleosol sequence are generally less than 100×10^(-8)m^(3)kg^(-1),significantly lower than those of the loess sections in the Chinese Loess Plateau,even though they are under similar climatic ***,the behaviors of the parameters related to the distributions of magnetic particles in these two regions are *** difference in the contents of ferrimagnetic minerals is the leading reason that caused the difference in their magnetic characteristics,but the mechanism is still open to ***,based on the analysis of thermomagnetic curves,a gradually increasing trend of the relative contents of maghemite over the last four glacial-interglacial cycles is *** realization of thermally unstable maghemite from Chinese loess leads us to speculate that the long-term increasing trend of the relative contents of maghemite in Titel loess-paleosol sequence likely is a mineralogical response to the progressive enhancement of continental climate in the Pannonian Basin since the Middle Pleistocene.

关键词： Eastern European loess Magnetic susceptibility pedogenesis Environmental magnetism Paleoclimate

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Comparing mineral weathering and elemental transport between earth's critical zone with different parent rocks in Yanshan Mountain,Hebei province,China

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Acta Geochimica 2022年第6期41卷 982-999页

作者： Zijian Sun Zhen Liao Wei Shen Daqing Fu Xiaofeng Wei Huiqiong Zhang Ziran Chen Lianghui Xiong Tianhao An Hao Wei School of Earth Sciences and Resources China University of GeosciencesBeijing100083China Beijing Institute of Geology for Mineral Resources CO. LTDBeijing100012China Sino-Zijin Resources CO. LTDBeijing100012China Hebei Huakan Resource Environmental Survey CO. LTDChengde067060HebeiChina Hebei Center for Ecological and Environmental Geology Research Hebei GEO UniversityShijiazhuang050031China

Bedrock weathering performs a significant influence on the evolution of Earth’s critical *** rock(dolostone),metamorphic rock(gneiss),and sedimentary rock(sandstone)geological formations in Yanshan Mountain,Hebei Province,are taken as objects to probe the controlling of geological formations on weathering characteristics,migration,and enrichment of elements as well as structure of Earth’s critical zone under the identical climate conditions through geological field survey,analysis on minerals component,element distribution in the weathering *** dolostone geological formation(DGF)is lithologically dominated by dolostone,characterized by the strongest and predominant chemical *** bedrock weathering and pedogenesis,DGF is marked by significant depletion of CaO,Mg O,S,Mn,Mo and enrichment of N,K,Fe_(2)O_(3),and Zn with concentrations of P,Cu,and B keeping *** of soil-forming materials and significant loss are driven by soil erosion,which results in thin regolith and *** soil thickness is less than 10 cm,and the regolith thickness is less than 30 *** vegetation community is predominantly rock arbor or brush,which is calcivorous and tolerant of *** is a dominant rock type of gneiss geological formation(GGF),characterized by the weakest weathering and fast chemical and physical weathering *** is masked by significant depletion of P,K,CaO,MgO,Fe_(2)O_(3),Mn,Cu and enrichment of N,S,Mo,and B,with contents of Zn keeping *** soil and regolith developed in GGF are relatively thick for one of the reasons that biotite expands during *** soil thickness is more than 50 cm,and the regolith thickness ranges from 100 to 200 *** vegetation community is predominantly high-quality economic forests and various arbors because of the enrichment of nutrients in *** is primarily a rock type of sandstone geological formation(SGF),characterized by moderate weathering degree and slow che

关键词： Yanshan Mountain Earth’s critical zone Rock weathering pedogenesis Migration and enrichment of element

Reliability of Relative Paleointensity Recorded in Chinese Loess-Paleosol Sediments

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Acta Geologica Sinica(English Edition) 2012年第5期86卷 1276-1288页

作者： YANG Tianshui LI Haiyan WU Huaichun YANG Zhenyu ZHANG Shihong HYODO Masayuki State Key Laboratory of Biogeology and Environmental Geology China University of GeosciencesBeijing 100083China School of the Earth Sciences and Resources China University of GeosciencesBeijing 100083China School of Ocean Sciences and Resources China University of GeosciencesBeijing 100083China Institute of Geomechanics Chinese Academy of Geological SciencesBeijing 100081China Research Center for Inland Seas Kobe UniversityKobe 657-8501Japan

A detailed paleomagnetic and rock-magnetic investigation spanning loess L7 to paleosol S8 has been carried out at the Baoji and Xifeng sections. Results of anisotropy of magnetic susceptibility confirm that the studied loess-paleosol sediments retain primary sedimentary fabrics. Stepwise thermal demagnetization shows that two well-defined magnetization components can be isolated from both loess and paleosol specimens. A low-temperature component, isolated between 100°C and 200°C, is consistent with the present geomagnetic field direction, and a high-temperature component, isolated between 200-300°C and 620-680°C, includes clearly normal and reversed polarities. Isothermal remanent magnetization and thermomagnetic analyses indicate that characteristic remanent magnetization is mainly carried by magnetite and hematite. The Day plot, together with the stratigraphic variations of rock-magnetic parameters, shows that the uniformity of magnetic mineralogy and grain size fulfills the criteria for relative paleointensity （RPI） studies. RPI records have been constructed using natural remanent magnetization （NRM） intensity after thermal demagnetization at 300°C normalized by low-frequency magnetic susceptibility （NRM 300 /χ）. The results show that the RPI record from the Baoji section, where pedogenesis is quite weak, is compatible with the stacked PISO-1500 paleointensity record, suggesting that it might reflect the paleointensity variation of the geomagnetic field. The RPI record from the Xifeng section, where pedogenesis is rather strong, indicates a clear dissimilarity with the stacked PISO-1500 paleointensity record, implying that it does not reflect the paleointensity variation of the geomagnetic field. Our new results show that the NRM 300 /χ from the strongly pedogenetic paleosols does not completely eliminate the pedogenetic （climatic） influence, so it might be unsuitable for a reliable paleointensity study.

关键词： Chinese loess pedogenesis relative paleointensity rock magnetism geomagnetic field

Plinthite and Its Associated Evolutionary Forms in Soils and Landscapes:A Review

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Pedosphere 2014年第2期24卷 153-166页

作者： P.N.EZE T.K.UDEIGWE M.E.MEADOWS Department of Environmental & Geographical Science University of Cape Town Department of Plant and Soil Science Texas Tech University

At elevated temperature regimes and abundant precipitation, mobilization and accretion of weathered iron oxides are promoted especially in a reduced environments in the tropics. This may lead to the formation of plinthite, which hardens irreversibly upon repeated wetting and drying to form petroplinthite. The need for this review stems from the seemingly dearth of information on the subject and a need to clarify different terms used in describing plinthite. We review various research works on plinthite and its associated pedogenic forms in the tropics. Furthermore, we proffer recommendations as to the most appropriate land use management practices that could help minimise the environmental and agronomic problems associated with plinthite and its related pedogenic forms. Parent material, temperature, seasonality and geomorphology are critical factors that influence soil water regime which in turn affect the pedogenesis of plinthite. Soil pH and mineralogy are additional factors that could also promote plinthite formation. Fossil plinthic soils are potential proxies for palaeoenvironmental reconstruction. Measures used in the management of plinthic soils include mechanically breaking the hardpans and the use of organic and inorganic amendments to modify the structure and chemistry of the soils. Avoidance of practices that would predispose soils to erosion would also prevent plinthization. We call for the relinquishment of the term ＂[aterite＂ which is a generM term for all forms of iron oxide-enriched earthy materials as used for plinthite. Plinthic horizon should also be incorporated into the United States Department of Agriculture Soil Taxonomy in view of its growing importance in soils.

关键词： agronomy pedogenesis petroplinthite soil taxonomy tropics