| 南极乔治王岛菲尔德斯半岛土壤的化学风化作用 |
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| 引用本文： | 刘耕年.南极乔治王岛菲尔德斯半岛土壤的化学风化作用[J].极地研究,1991,2(1):22-29. |
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| 作者姓名： | 刘耕年 |
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| 摘 要： | 西南极南设得兰群岛乔治王岛菲尔德斯半岛土壤化学分析表明土壤中存在着一定的化学风化作用。相对于母质,土壤中的SiO_2、Al_2O_3、Fe_2O_3、FeO、MgO,GaO和Na_2O淋失,K_2O、H_2O~+、H_2O~-、TiO_2和P_2O_5富集。土壤中SiO_2/Al_2O_3的平均值为4.71,属弱风化壳类型。硅铝比反映出成土作用时间越长,土壤的风化程度越高,化学风化作用大于南极大陆边缘和内部。Al_2O_3在南极的淋失率大于SiO_2,使较老土壤剖面由下向上硅铝比增大。土壤的化学性质很大程度上取决于母质。南极强烈的冻融扰动作用破坏了土壤分层。土壤中存在着较强的水合作用。
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| 关 键 词： | 化学风化 淋失 富集 硅铝比 菲尔德斯半岛 |
REPEATED COMPRESSION-ANNEALING EXPERI- MENTS ON ANISOTROPIC CORE ICE |
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| Abstract: | Three runs (6 samples) of repeated uniaxial compressionannealing experiments were conducted on a creep testing machine with a loading accuracy of 1 % at-2±0.2℃. The tested samples were cut from BHQ ice core. Compression axes were parallel, at an angle of 45°and normal to the vertical of the core respectively. The initial orientation fabrics of samples were single-maximum pattern or approximate single-maximum pattern with different mean grain size. The sample was compressed with an initial axial stress of 0.8 MPa, until 10% axial strain was obtained, and then annealed for 72 hours. Such compression-annealing procedure was lepeated 6 times for a run.
The experimental result shows that under a warm temperature and large load, the initial features of structure and fabric disappear finally, and n small circle girdle fabric with fine equigranular grains appears, and a multi maxima fabric developes to seme extent. Analysis of structure and fabric shows that the formation mechanism of new fabrics in these experiments is principally recrystallization. With the repetition of compression-annealing, the difference in the fabric of the six samples is reducing, their rheological behavior tends to be uniform, and their grain size decreases towards a steaty state value. |
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