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101.
102.
灰岩成因-结构分类的进展及其相关问题讨论 总被引:11,自引:0,他引:11
由Folk在1959,1962年及Dunham在1962年所提出的灰岩因-结构分类体系,具有划时代的意义,至今还得到极为广泛的应用,Embry和Klovan在1971年关于生物礁灰岩的成因-结构分类,即关于骨架灰岩,障积灰岩,粘结灰岩的成因-结构分类的第一次重要的补充,它解决了与生物作用有关的灰岩不符合Folk和Dunham的结构成熟度概念的矛盾,而对成岩作用及其产物的更深入研究,地质学家们发现了许多布成岩作用形成的泥晶化作用和颗粒化作用,由它们所形成的岩石也不符合Folk和Dunbam的结构成熟度概念,导致了Wright在1992年提出了一个更完整的灰岩成因-结构分类体系,把灰岩分为生物作用类,沉积作用类及成岩作用类三大类,即Folk和Dumban描述的分类均属于沉积作用类。要特别指出的是,在从松散沉积物到已石化的竖硬石头的成岩过程中,不但灰岩的结构会发生变化,而且组分也会发生变化,从而使灰岩的成因-结构分类变得更加复杂,关于这方面还存在许多有待进一步研究的问题。在审视Wright在1992年的分类体系时,有必要在沉积作用类中增加“非正常沉积作用亚类灰岩”,针对许多非礁相地层中发育的由生物礁岩石构成的生物层及生物丘,因而有必要对生物作用灰灰岩进行更进一步的分类。 相似文献
103.
胶东海阳所堆积辉长岩的变质反应结构、石榴石形成及P—T演化 总被引:5,自引:0,他引:5
海阳所堆积辉长岩由橄长岩、橄榄辉长岩和辉长岩组成。在橄长岩和橄榄辉长岩中发育有典型的变质反应结构:主要为橄榄石与斜长石之间形成由斜方辉石、尖晶石、角闪石和石榴石等矿物组成的多期次次变边,并有三个不同世代变质矿物,早期Cpx+Opx+Spl,中期Amp,晚期Grt;期次是钛铁矿与斜长石之间形成石榴石次变边,相对比较简单,只有一个世代变质矿物,为Grt+Amp+Rut或Grt+Rut岩中石榴石是通过斜长石与角闪石或斜长石与钛铁矿之间的变质反应形成的,虽为峰值变质作用的产物,但变质反应的期次及类型不同导致了所形成石榴石的温度和压力有所不同。堆积辉长岩形成演化的温压计算表明,堆积辉长岩在经过近等压降温的岩浆作用之后的变质作用早期,仍为近等压降温,而晚期则表现为近等温升压。这一特殊的P-T演化可能反映了堆积辉长冷侵位与深俯冲特征。 相似文献
104.
柯树北岩体岩石谱系单位的建立及构造环境分析 总被引:1,自引:0,他引:1
柯树北岩体为陆壳改造型(S型)花岗岩,具有结构和成分演化序列,运用岩石结构列序法,将其划分为6个单元,归并为1个超单位,按侵入体空间展布形式,岩体地质学,岩石学,构造地球化学等资料,提出了岩浆侵位是受区域拉张应力控制的认识。 相似文献
105.
Su Young Lee Masatsugu Ohnishi Yasuhiro Shibata Makoto Wwatanabe Kenichi Hoshino Mayumi Jige Xiangping Gu Hitoshi Chiba Tamotsu Oomori Kantaro Fujioka Peter A. Rona 《Resource Geology》2001,51(1):63-68
Abstract: Pyrite rich in Zn, up to 3.1 wt%, was found in the TAG active mound of the TAG hydrothermal field, the slow-spreading Mid-Atlantic Ridge at 26°08'N and 44°49'W. The Zn-rich pyrite is characterized by an optical homogeneity, a homogeneous distribution of Zn in the back-scattered electron images, both at a magnification of about 500, a negative correlation between Fe and Zn contents of the pyrite and a rather small unit cell edge (a0 = 5.4117 ± 0.0008Å), strongly indicating that the detected Zn is present in the pyrite in solid solution. Such Zn concentrations are observed exclusively in dendritic pyrite, suggesting that the Znrich pyrite grew from hydrothermal fluids of a high degree of supersaturation due to quenching on the seafloor. 相似文献
106.
Partitioning of heavy metals on soil samples from column tests 总被引:3,自引:0,他引:3
R. N. Yong W. Z. W. Yaacob S. P. Bentley C. Harris B. K. Tan 《Engineering Geology》2001,60(1-4):307-322
In this study, column tests were used to determine the retention capability of three types of estuarine alluvia collected adjacent to landfill sites in South Wales. Selective sequential extraction (SSE) was used to study the retention mechanisms of heavy metals in the soil columns obtained from leaching experiments. Acid digestion was later used to check the validity of the SSE results. Breakthrough curves show good retention of heavy metal ions (Pb, Cu, and Zn) by all soils, where almost 99% of heavy metals were retained with the Ce/Co values in the order of 10−3. The retention strength of these soils was observed to be constant up to five pore volumes (PV). This corresponds with the pH of the effluents and pore water of soil slices, which also show good buffering capacity against very acidic leachate up to 5PV. The heavy metal extraction profiles from SSE show very similar trends with the retention profiles from the leaching experiments, where heavy metals were retained mainly at the top part where the leachate entered the column. SSE indicates qualitatively that heavy metals precipitated with carbonates and amorphous materials (oxides/hydroxides) are higher than heavy metal retention via exchangeable mechanisms. The mass balance calculation gives range of deviation of 1–16% of the total soil extraction. The distribution of the heavy metals with various soil constituents are ranked in the following order: Carbonates>Amorphous oxides hydroxides>Organic matter>Exchangeable phases. 相似文献
107.
针对纹理影像先估计出其马尔可夫随机场参数,后运用多元统计分析中模糊聚类分析的数学方法进行定量分类,从而为解决划分上的不确定性现象找出描述方法,获得客观的分类结果 相似文献
108.
Many observations and studies indicate that pore fluid pressure in the crustal rocks plays an important role in deformation, faulting, and earthquake processes. Conventional models of pore pressure effects often assume isotropic porous rocks and yield the nondeviatoric pressure effects which seem insufficient to explain diverse phenomena related to pore pressure variation, such as fluid-extraction induced seismicity and crustal weak faults. We derive the anisotropic effective stress law especially for transversely-isotropic and orthotropic rocks, and propose that the deviatoric effects of pore fluid pressure in anisotropic rocks not only affect rock effective strength but also cause variation of shear stresses. Such shear stress variations induced by either pore pressure buildup or pore pressure decline may lead to faulting instability and trigger earthquakes, and provide mechanisms for the failure of crustal weak faults with low level of shear stresses. We believe that the deviatoric effects of pore fluid pressure in anisotropic rocks are of wide application in studies of earthquake precursors and aftershocks, oil and gas reservoir characterization, enhanced oil recovery, and hydraulic fracturing. 相似文献
109.
Judy Ehlen 《地球表面变化过程与地形》1992,17(1):53-67
The granite tors of Dartmoor are characterized by using the regional spatial patterns of 21 geomorphic, petrographic, and structural variables. The data were derived from topographic maps, field measurement, and laboratory analysis of rock samples collected in the field. Identification of spatial patterns and comparison of patterns between variables were made on contour maps generated from the data using ARC/INFO. Three tor types—summit tors, valleyside tors, and spur tors—are semiquantitatively characterized using these data and procedures. The three types of tors are distinguished with respect to variations in relative relief, joint spacing and joint type, rock texture, grain size, and composition. Summit tors have the highest relative relief (mean: 125·7 m), contain the most potassium feldspar (>30 per cent), and have the most widely-spaced primary vertical (>300 cm) and secondary horizontal joints (> 10 cm). The rocks are the most megacrystic (> 15 per cent) and the coarsest grained. Plagioclase is also abundant in summit tors. Valleyside tors have the lowest relative relief (mean: 72·9 m) and the most widely-spaced horizontal joints (primary, 60-200 cm; secondary, > 10 cm). Grain size, vertical joint spacing, and quartz and potassium feldspar abundances are intermediate. The shapes of valleyside tors are controlled by horizontal joints and the rocks are either very feebly magcrystic or equigranular in texture. Spur tors have intermediate relative relief (mean: 115·4 m), the narrowest joint spacing (vertical joints, < 200 cm, 50-75 cm; horizontal joints <60 cm, < 10 cm) and the finest grain. In addition, the rocks are feebly magacrystic. 相似文献
110.
介绍了空间灰度相关法的11个纹理特征。试验表明,仅3个是描述性强的纹理特征。通过用t检验法来分类纹理,发现该方法具有良好的“去伪”特性,可辅助其它纹理分类。 相似文献