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1.
青木关岩溶槽谷流域不同土地利用类型土壤可蚀性分析 总被引：2，自引：0，他引：2
基于土壤实地采样和理化性质测试分析,采用EPIC模型K值计算方法,分析青木关岩溶槽谷流域的土壤理化性质、土壤可蚀性及其影响因子。结果发现:（1）青木关岩溶槽谷流域表层土壤（0~10 cm）可蚀性K值介于0.037 1~0.060 5之间,均值为0.048 5,中值为0.047 5,变异系数为10.71%,偏度和峰度值小于1;（2）表土机械组成中以粉粒含量为主,土壤质地属于粉壤土;有机质含量在13.98~52.24 g.kg-1之间,均值为29.20 g.kg-1;表土可蚀性K值与砂粒含量、有机碳含量呈极显著负相关,与粉粒含量呈极显著正相关,与黏粒含量呈负相关;（3）不同土地利用类型下的表土可蚀性K值以裸土地最大,为0.058 3,耕地次之,为0.053 4,其次为园地、荒草地和竹林,分别为0.048 3、0.047 8和0.046 9,针阔叶混交林最小,为0.0427,分别存在显著差异（P＜0.05）,变异系数介于2.7%～6.1%之间;受人类活动影响强烈的裸土地和耕地是本地区主要的泥沙策源地,恢复植被能有效提高土壤抗蚀能力;（4）不同土地利用类型土壤剖面K值均值为耕地（0.056 3）显著大于荒草地（0.051 6）与林地（0.048 1）（P＜0.05）,荒草地与林地K值间差异性不显著;K值剖面分布一致表现为0~35 cm相对较小且变化较大,土下35~60 cm随着深度的增加而增大。 相似文献
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为了查清耕地表层土壤中锗特色元素的分布特征及富集机理,通过对贵州省仁怀市耕地土壤野外调查、采样和测试等研究分析,总结了锗元素含量的地球化学特征和影响因素,探讨了土壤类型、土地利用方式、土壤地球化学性质、成土母岩时代与锗含量的关系,结果表明,仁怀市耕地土壤锗元素平均含量与贵州省土壤背景值及中国土壤平均值相比,含量均高,高含量区域主要分布在寒武纪、二叠系、三叠纪地层母质区中。综合分析,土壤中Ge与pH值呈弱负相关,与SOM、Co 、Zn呈弱正相关性,与Cu、Pb呈中等程度正相关;酸性土壤富锗概率大于中性碱性环境;不同土地利用类型中,裸地、水浇地中Ge元素含量平均值较高;不同土壤类型中,石灰土、水稻土中Ge元素含量平均值较高;研究区内铅锌带与耕地土壤Ge元素高值分布带较为一致。 相似文献
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中国北方土壤风蚀问题研究的进展与趋势 总被引：70，自引：0，他引：70
土壤风蚀是中国北方土地退化的主要原因之一。国内土壤风蚀的研究工作相对比较薄弱，所取得的进展主要包括区域性的土壤风蚀分布地带性规律和不同时间尺度的准周期性规律，描述性的风蚀强度分级与危害评价，单因子风蚀过程的风洞实验，农田风蚀防治等方面。今后的研究趋势主要表现在土壤风蚀的物理本质、影响因素及发展动态的综合研究，土壤理化性质与表面性质对抗蚀性的影响及其与风蚀的反馈关系，土壤风蚀的基本过程及防治原理，土壤风蚀预报方程与数字模拟，土壤风蚀影响评价模型，土壤风蚀与土地利用以及全球变化的关系，各种观测与实验设备的研究等方面。 相似文献
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岩溶山地典型植被恢复过程中土壤理化性质及微生物特征 总被引：1，自引：0，他引：1
探讨了岩溶山地耕地、1年退耕地、灌草地、15年侧柏疏林地、25年侧柏次生林地植被恢复过程中土壤理化性质和微生物特征的变化。结果表明土壤随着植被恢复的进行,容重先升高后降低,总孔隙度与之相反;各恢复阶段（退耕地、灌草地、疏林地、次生林地）表土＞0.25 mm水稳定性团聚体含量较耕地的增幅为5.1%～12.5%,以疏林地最高;团聚体结构破坏率依次降低,各恢复阶段较耕地降幅为34.0%～64.7%,与有机质呈负相关;全N、碱解N等肥力因子含量总体呈逐渐增加的趋势;各恢复阶段中以灌草地pH值最高;表土微生物总数先降后升,各阶段细菌占微生物总数的66.7%～93.3%,放线菌占4.2%～28.8%,同时细菌也是土壤呼吸的主要贡献者。土壤特征的差异性是地表植物组成、凋落物成分及不同指标之间综合作用的结果。 相似文献
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模拟酸雨对阳离子在土体内迁移的影响 总被引：16，自引：4，他引：12
利用室内模拟酸雨的土柱实验,研究了在红壤表土施用钾肥后酸雨对不同土层交换性阳离子迁移的影响.结果表明,在不同土体深度,表土直接受酸沉降的淋溶,也是最容易发生酸化的土层, pH 2.5酸雨淋溶后,表土 pH值下降到 3.5～ 4.2,这是铝的缓冲范围,且土壤交换性 H 和 Al3 含量的增加显示出土壤对酸沉降的缓冲效率和缓冲能力的急剧减弱; pH 4.5酸雨淋溶后, A和 B层土壤 pH值上升了 0.3～ 0.5,其机理与的专性吸附释放 OH-有关;表土施用钾肥后, K 交换土壤表面的 H 和 Al3 ,引起土壤交换性 H 和 Al3 向下迁移;不同 pH值的酸性降雨引起土壤中交换性阳离子向下迁移和淋失的程度也有明显的差异, pH 2.5酸雨淋溶后土壤溶液中钾的含量高于 pH 4.5酸雨淋溶的,但交换性钾含量低于后者; pH 2.5和 pH 4.5酸雨淋溶后交换性钙的淋失量分别占原土的 50%～ 70%和 20%～ 40%,这表明酸雨淋洗会导致养分库的损耗,造成土壤养分贫瘠. 相似文献
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云南个旧锡矿区大屯盆地土壤重金属污染与生态风险评价 总被引：9，自引：1，他引：8
土壤中的重金属直接影响农业安全生产,掌握不同耕地和土壤类型中重金属的污染程度可为削减生态风险提供依据。通过实地调查,对云南个旧锡矿区松树脚矿大屯盆地不同耕地和土壤类型的重金属含量,采用单因子指数法、内梅罗综合污染指数法进行污染评价,基于潜在生态危害指数法进行生态风险评价。结果表明,As、Cd、Cu、Cr、Ni、Pb和Zn七种元素中,As和Cd是大屯盆地农田土壤的主要污染因子,两者对污染程度的贡献率为97%,其中Cd的贡献率为68%;两者对生态风险的贡献率为87%。旱地重金属污染程度和生态风险大于水田,红壤中重金属的污染程度和生态风险大于红色石灰土。从空间来看,个旧大屯盆地重金属污染程度总体呈现从西南向东北逐渐降低的趋势。 相似文献
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云南小江流域不同土地利用类型土壤微量元素的对比分析 总被引：1，自引：0，他引：1
文章对云南小江流域不同土地利用类型（耕地、林地、园地、建设用地、裸地）土壤的微量元素进行空间插值、方差分析和相关性研究,旨在探讨云南小江流域不同土地利用类型微量元素的分布和迁移规律。结果表明:除Mo的含量较低外,小江流域土壤中Cu、Mn、Ni和Zn的含量普遍较高。各微量元素含量在不同土地利用类型中具有明显的差异性,园地土壤微量元素含量最高。微量元素的变异程度均属于中等变异。Cu、Mn、Mo、Ni、Zn的空间分布具有一定的相似性,高值区主要集中在海拔较低的岩溶河谷区右侧和盆底沉积平坝区,主要土壤类型为碳酸盐岩红壤;低值区集中在海拔较高的河谷区左侧和中山区,主要土壤类型为碎屑岩。地貌、土壤母岩和人为活动是影响微量元素分布和迁移的重要因素。 相似文献
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为定量化分析地理因子对土壤中铜（Cu）、钴（Co）、钼（Mo）和锌（Zn）空间分异的影响,作者采集和测定了四川盆地长寿之乡江津区156件表土样品,综合运用数理统计、地统计和地理探测器等方法,分析表土中Cu、Co、Mo和Zn含量的空间分异特征及其驱动因子。表土中Cu、Co、Mo和Zn均值分别为27.0×10-6、18.5×10-6、0.4×10-6和216.8×10-6,分别是中国土壤背景值的1.19倍、1.45倍、0.20倍和2.17倍。研究区表层土壤中Cu（36.6%）、Co（16.9%）、Mo（51.7%）和Zn（89.4%）变异系数都呈中等变异,但Zn和Mo的空间分布不均匀性更加显著。总体上,江津区表土中Cu、Co、Mo和Zn含量在北部相对较高,而南部地区相对较低。土壤中Fe和Mn及成土母岩和土壤类型分别是影响江津区表土中Cu、Co、Mo和Zn空间分异的主控驱动因子,但影响程度不一。总体上,Fe和Mn的独立及交互作用最高,对江津区表土中Cu、Co、Mo和Zn含量的空间分异起到重要作用。 相似文献
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Emily Keeble David I. Whiteside Michael J. Benton 《Proceedings of the Geologists' Association. Geologists' Association》2018,129(2):99-119
Pant-y-ffynnon Quarry in South Wales yielded a rich cache of fossils in the early 1950s, including articulated specimens of new species (the small sauropodomorph dinosaur Pantydraco caducus and the crocodylomorph Terrestrisuchus gracilis), but no substantial study of the wider fauna of the Pant-y-ffynnon fissure systems has been published. Here, our overview of existing specimens, a few described but mostly undescribed, as well as freshly processed material, provides a comprehensive picture of the Pant-y-ffynnon palaeo-island of the Late Triassic. This was an island with a relatively impoverished fauna dominated by small clevosaurs (rhynchocephalians), including a new species, Clevosaurus cambrica, described here from a partially articulated specimen and isolated bones. The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of clevosaurs in the palaeo-archipelago. The larger reptiles on the palaeo-island do not exceed 1.5?m in length, including a small carnivorous crocodylomorph, Terrestrisuchus, and a possible example of insular dwarfism in the basal dinosaur Pantydraco. 相似文献
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Gilles Serge Odin 《Comptes Rendus Geoscience》2002,334(6):409-414
Lithostratigraphy, physicochemical stratigraphy, biostratigraphy, and geochronology of the 77–70 Ma old series bracketing the Campanian–Maastrichtian boundary have been investigated by 70 experts. For the first time, direct relationships between macro- and microfossils have been established, as well as direct and indirect relationships between chemo-physical and biostratigraphical tools. A combination of criteria for selecting the boundary level, duration estimates, uncertainties on durations and on the location of biohorizons have been considered; new chronostratigraphic units are proposed. The geological site at Tercis is accepted by the Commission on Stratigraphy as the international reference for the stratigraphy of the studied interval. To cite this article: G.S. Odin, C. R. Geoscience 334 (2002) 409–414. 相似文献
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The effect of water on accessory phase solubility in subaluminous and peralkaline granitic melts 总被引：4，自引：0，他引：4
The solubilities of columbite, tantalite, wolframite, rutile, zircon and hafnon were determined as a function of the water contents in peralkaline and subaluminous granite melts. All experiments were conducted at 1035 °C and 2 kbar and the water contents of the melts ranged from nominally dry to approximately 6 wt.% H2O. Accessory phase solubilities are not affected by the water content of the peralkaline melt. By contrast, solubilities are affected by the water content of the subaluminous melt, where the solubilities of all the accessory phases examined increase with the water content of the melt, up to 2 wt.% H2O. At higher water contents, solubilities are nearly constant. It can be concluded that water is not an important control of accessory phase solubility, although the water content will affect diffusivities of components in the melt, thus whether or not accessory phases will be present as restite material. The solubility behaviour in the subaluminous and peralkaline melts supports previous spectroscopic studies, which have observed differences in the coordination of high field strength elements in dry vs. wet subaluminous granitic glasses, but not for peralkaline granitic glasses. Lastly, the fact that wolframite solubility increases with increasing water content in the subaluminous melt suggests that tungsten dissolved as a hexavalent species. 相似文献
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Muriel Rocher Stéphane Baize Stéphane Jaillet Edward Marc Cushing Yannick Lozac&#x;h Francis Lemeille 《Comptes Rendus Geoscience》2003,335(8):701-708
Calcite samples were extracted both from the rock matrix and the superficial coating of a karstified fault plane of an underground quarry, located in the eastern border of the Paris basin. The karstification is dated as Quaternary. Analysis of mechanical calcite twinning reveals that only the calcite matrix has also undergone a compression trending WNW that can be attributed to the Mio-Pliocene alpine collision. Both coating and matrix have undergone a strike-slip regime with σ1 roughly trending north–south, that could correspond to the regional present-day state of stress, a strike-slip compression rather trending NNW, modified by local phenomena. To cite this article: M. Rocher et al., C. R. Geoscience 335 (2003). 相似文献
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正20141756 Chen Ruige(Mathematical College,China University of Geosciences,Beijing100083,China);Zhou Xun Numerical Simulation of Groundwater Level Fluctuation in a Coastal Confined Aquifer with Sloping Initial Groundwater Level Induced by the Tide(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(7),2013,p.1099-1104,6 illus.,16 refs.) Key words:confined water,groundwater level 相似文献
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正20141408 Cai Jia(Institute of Geology,Chinese Academy of Geological Sciences,Beijing100037,China);Liu Fulai Petrogenesis and Metamorphic P-T Conditions of Garnet-Spinel-Biotitebearing Paragneiss in Danangou Area,Daqingshan-Wulashan Metamorphic Complex Belt(Acta Petrologica Sinica,ISSN1000-0569,CN11-1922/P,29(7), 相似文献
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正20142386An Guoying(China Aero Geophysical Survey and Remote Sensing Center for Land and Resources,Beijing 100083,China)Application of Satellite Remote Sensing in Regional Hydrogeological Investigation:Taking Cenozoic Strata in Wenquan Sheet(1∶250 000)of Karakoram Range as an Example(Geosci- 相似文献
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正20141016An Chengbang(Key Laboratory of Western China’s Environmental Systems,Ministry of Education,Lanzhou University,Lanzhou 730000,China);Zhao Yongtao Lake Records during the Last Glacial Maximum from Xinjiang,NW China and Their Climatic Impli- 相似文献
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正20141538 Cao Qing(School of Earth Sciences and Engineering,Xi’an Petroleum University,Xi’an 710065,China);Zhao Jingzhou Characteristics and Significance of Fluid Inclusions from Majiagou Formation,Yichuan Huangling Area,Ordos Basin(Advances in Earth Science,ISSN1001-8166,CN62-1091/P,28(7),2013,p.819-828,7 illus.,3 tables,43 refs.) 相似文献