共查询到18条相似文献,搜索用时 479 毫秒
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通过天青石菊花石形貌与红柱石菊花石钟乳石截面放射状形貌的对比,找出它们形成的共同规律,并从形貌细节差异上分析了其形成机制和条件的差别。 相似文献
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通过对广西来宾菊花石的野外工作及其形貌观察、电子探针成分分析、偏光显微镜鉴定,阐明了菊花石(chrysanthemum
stone)的分布和形貌特征及其
后生变化规律,认为菊花石主要由天青石、方解石和玉髓三种矿物组成。天青石(SrSO 相似文献
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华南地区栖霞组菊花状天青石的交代及其地质意义 总被引:4,自引:0,他引:4
本文在收集大量菊花石标本的基础上,通过岩石薄片镜下鉴定及X射线衍射分析,识别了华南地区栖霞组菊花石假象内矿物的成因类型,建立了矿物交代序列,并通过对菊花石假象内各种矿物成分的电子探针分析和对交代方解石,脉方解石及其围岩的氧,碳同位素分析,探讨了菊花石交代过程中的成岩环境,合理地解释了菊花石内正延性玉髓和栖霞组内海泡石的成因。 相似文献
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对所建立的菊花石生长模型进行了详细的数理分析.菊花石生长模型具分形特点,其豪斯道夫维数为:1<D<1+ln2/ln(2β)(β≥1),说明菊花石形态不同于一维柱体(虽然它是由柱体放射状集合而成),也不同于三维球体(虽然它是一个似球状的花体);D同时还蕴含着结晶行为上的物理意义,即D=1时无分叉成核行为,D>1时有分叉成核行为,且D越大分叉成核越多;无核生长比有核生长的D大等等.本模型的D在1~1+ln2/ln(2β)(β≥1)之间的多变性可与多重分形类比,且可与扩散限制聚集(DLA)模型周界点集的多分维特点类比. 相似文献
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华南地区栖霞组“菊花石”假象与海泡石矿成因关系探讨 总被引:1,自引:0,他引:1
根据对华南地区二叠系栖霞组内菊花石假象的成因研究,结合对该组内燧石结核,菊花石内正延性玉髓和海泡石形成时代关系的现状关系的观察,认为华南地区栖霞组内的海泡石形成于早期成岩作用过程中,与该组内燧石结核和菊花石假象内的正延性玉髓同期形成,其成因既与高盐度的沉积环境或高盐度的成岩环境条件无关,也与热液活动无关。 相似文献
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华南栖霞组菊花石假象内正延性玉髓的成因及其地质意义 总被引:1,自引:2,他引:1
正延性玉髓常被视为干旱蒸发沉积环境的标志。正延性玉髓亦广泛分布于华南地区栖霞组菊花石 (目前绝大多数为天青石假象 )内。本文在天青石后期矿物交代序列识别的基础上,通过对菊花石内各期次碳酸盐交代矿物的电子探针分析,发现菊花石内正延性玉髓形成于富含硫酸根离子和镁离子的成岩介质条件中。结合已有的正延性玉髓研究报道和栖霞组的沉积、成岩作用环境特征分析,认为华南地区栖霞组菊花石内正延性玉髓的形成环境与高蒸发沉积环境或高盐度成岩环境无关。因此,仅根据正延性玉髓的出现不足以确定沉积或成岩环境的盐度条件。 相似文献
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庐山菊花石是一种天然观赏石,它的切面形似菊花,花形优美,蕴意深刻。它的形成与保存具特定的地质建造及构造条件,因此罕见珍贵,作者探讨了它的价格评定原则。 相似文献
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陕西省观赏石资源分为单矿物玉石类、岩石玉类、卵石与水冲石及古生物化石四大类。著名的观赏石有水晶、萤石、绿松石、五彩石、芙蓉石、商洛翠玉、粉翠、菊花石、蓝田玉、洛南翠、黄陵石、磬玉石、墨玉、汉江石、秦岭石、泾河石、洛河源头石、陕西省黄河石、嘉陵江石及古生物化石等。 相似文献
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刘德镒 《沉积与特提斯地质》1988,8(Z1):41-50
菊花石是天青石矿物在岩石中呈三度空间发育的放射状集合体。白色或微带黄色色调,半透明,因状如菊花故得名。湖南浏阳是盛产此珍贵石雕工艺品原料之地,故名浏阳式菊花石浏阳菊花石已有一百多年的开采历史,在1915年巴拿马国际博览会上荣获金奖。但在矿物学上的进一步认识,以及在地质学上把它作为一种找矿标志来加以重视,却是近几年的事。它赋存于华南二叠纪碳酸盐岩中,与世界上稀缺的海泡石粘土同属一个层位,密切共生,因而成为华南寻找海泡石的一个重要宏观标志。其分布如图1所示。 相似文献
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Response of multilayer geosynthetic-reinforced bed resting on soft soil with stone columns 总被引:2,自引:0,他引:2
In the present study, a mechanical model has been developed to study the behavior of multilayer geosynthetic-reinforced granular fill over stone column-reinforced soft soil. The granular fill and geosynthetic reinforcement layers have been idealized by Pasternak shear layer and rough elastic membranes, respectively. The Kelvin–Voight model has been used to represent the time-dependent behavior of saturated soft soil. The stone columns are idealized by stiffer springs and assumed to be linearly elastic. The nonlinear behavior of the soft soil and granular fill is considered. The effect of consolidation of soft soil due to inclusion of the stone columns on settlement response has also been included in the model. Plane strain conditions are considered for the loading and reinforced foundation soil system. An iterative finite difference scheme is applied for obtaining the solution and results are presented in nondimensional form. It has been observed that if the soft soil is improved with stone columns, the multilayer reinforcement system is less effective as compared to single layer reinforcement to reduce the total settlement as there is considerable reduction in the total settlement due to stone column itself. Multilayer reinforcement system is effective for reducing the total settlement when stone columns are not used. However, multilayer reinforcement system is effective to transfer the stress from soil to stone column. The differential settlement is also slightly reduced due to application of multiple geosynthetic layers as compared to the single layer reinforcement system. 相似文献
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Kousik Deb 《国际地质力学数值与分析法杂志》2008,32(10):1267-1288
The present study pertains to the development of a mechanical model for predicting the behavior of granular bed‐stone column‐reinforced soft ground. The granular layer that has been placed over the stone column‐reinforced soft soil has been idealized by the Pasternak shear layer. The saturated soft soil has been idealized by the Kelvin–Voigt model to represent its time‐dependent behavior and the stone columns are idealized by stiffer Winkler springs. The nonlinear behavior of the granular fill has been incorporated in this study by assuming a hyperbolic variation of shear stress with shear strain as in one reported literature. Similarly, for soft soil it has also been assumed that load‐settlement variation is hyperbolic in nature. The effect of consolidation of the soft soil due to inclusion of the stone columns has also been included in the model. Plane‐strain conditions are considered for the loading and foundation soil system. The numerical solutions are obtained by a finite difference scheme and the results are presented in a non‐dimensional form. Parametric studies for a uniformly loaded strip footing have been carried out to show the effects of various parameters on the total as well as differential settlement and stress concentration ratio. It has been observed that the presence of granular bed on the top of the stone columns helps to transfer stress from soil to stone columns and reduces maximum as well as differential settlement. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
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华南地区栖霞组沉积地球化学特征研究 总被引:7,自引:3,他引:4
利用多元统计分析方法对广西来宾铁桥剖面栖霞组层纹灰岩和江西慈化洪桥剖面栖霞组粒泥灰岩的岩石地球化学特征进行了分析;对广西来宾铁桥剖面栖霞组的灰岩样品40件及该剖面中产出的菊花石样品8件、江西慈化洪桥剖面的粒泥灰岩样品8件、浏阳永和剖面的灰岩样品10件及该区产出的菊花石样品3件进行了黄铁矿矿化程度(DOP值)的测定分析,分析结果表明华南地区的DOP值多数大于0.42;结合岩石微量元素比值特征的分析,表明华南地区栖霞组灰岩形成于缺氧的沉积环境.DOP值的变化趋势为:浏阳>来宾>慈化,表明华南地区3个剖面的沉积环境含氧量的关系为:浏阳<来宾<慈化.DOP值在3个剖面上的周期性变化与剖面中的沉积旋回相对应,亦表明沉积环境的含氧量呈周期性变化. 相似文献
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