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宋友桂 《华东地质学院学报》2009,32(4):313-323
沉积矿物学是界于沉积学与矿物学之间的边缘交叉学科,它通过沉积物（岩）中矿物的组成、含量、组合特征、成因和单矿物化学成分、晶体结构、形态、性质的分析,研究沉积物在搬运、风化剥蚀、沉积过程和成岩过程中矿物的物理、化学行为特征．进而研究它们在时间、空间上的分布特征与规律,从而探讨物质来源、成因、形成演化历史与环境变迁等。近些年来沉积矿物学在研究古气候、物质来源、沉积环境、油气勘探以及构造演化中发挥着重要作用,成为古环境恢复与重建的重要研究手段之一。在阐述粘土矿物、重矿物、碳酸盐类矿物等的古环境意义的基础上,对其近20a来在湖泊、黄土、海洋古环境恢复当中的应用进展进行了回顾和评述。随着新的沉积矿物研究方法的不断出现和应用,结合沉积物的物理指标、化学指标以及古生物学等其他指标,沉积矿物学将在古环境重建中发挥越来越重要的作用,具有广阔的应用前景。 相似文献
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粘土矿物在气候环境变化研究中的应用进展 总被引：1，自引：0，他引：1
在古环境和古气候的重建中,粘土矿物和碳-氧同位素、孢粉、树轮、冰芯等代用指标一样具有同等重要的地位。在没有地质构造运动影响时,气候是影响粘土矿物形成的主要因素,沉积物中的粘土矿物可用来分析古气候和古环境。粘土矿物及其组合可以独立或作为主要指标反映气候和环境变化,并已应用于高分辨率的晚第四纪地层的气候环境研究中。粘土矿物在很短的时间内也会发生明显地变化,不仅可以反映千年-百年尺度的气候环境变化,而且也可以反映几十年尺度的古气候环境变化过程。粘土矿物与其它指标对同一气候环境响应的相位差有待深入研究。不同的半定量分析方法测量出的同一剖面中粘土矿物的含量变化趋势和特征具有一致性。 相似文献
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对青藏高原北缘共和盆地沙珠玉河的尾闾湖达连海钻孔沉积柱(40.92 m)进行了~(14)C年代测定(10个控制点)和粘土矿物分析(按20cm/70 a间隔的分辨率)。沉积柱底部年龄为14.5 cal ka BP。根据沉积柱粘土矿物的类型、组合、比率指标综合分析,重建了共和盆地14.5 cal ka BP以来气候环境的演化历史。冰消期(14.5~10.0 cal ka BP)盆地气候总体特征表现为干冷,盆地物理风化强:早中全新世(10.0~5.0 cal ka BP)气候表现为温湿,盆地化学风化为主,气候最宜期发生在中全新世的6.0 cal ka BP前后;晚全新世(5.0~0.0 cal ka BP)气候表现为干冷,盆地物理风化盛行。末次冰消期以来,共和盆地粘土矿物记录的气候环境变化阶段与高原其它湖泊指标记录的阶段基本一致。共和盆地粘土矿物记录的气候环境兼有西风、季风模式的特征。 相似文献
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14过渡矿物是广泛发育的典型成土作用产物,其矿物学特征及含量变化不仅能记录成土时期的气候、环境条件,也可以作为这些土壤发生分类和类型区分的依据。通过对有关14过渡矿物研究成果系统全面的分析,阐明了这种过渡矿物的谱学特征、层间离子类型、鉴定依据及其成因,并在此基础上提出对14过渡矿物的鉴定实验流程。此外,高分辨透射电子显微技术的应用给14过渡矿物的研究提供了极大的保障,利用高分辨透射电子显微镜可以研究14过渡矿物的形成、转化关系。14过渡矿物对气候环境十分敏感,且形成于特征的干湿交替、适度的风化及弱酸性环境条件,因此,这种过渡矿物有望作为成土时期的气候环境代用指标。 相似文献
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我国不同气候带黄土中粘土矿物组合特征分析 总被引：11，自引：1，他引：10
在兰州黄土和下蜀黄土中粘土矿物的X衍射分析基础上,对我国不同纬度和气候带的五个黄土剖面(点)中的粘土矿物组合和空间分布进行了对比分析,并探讨了与古气候的关系。结果表明,黄土中粘土矿物组合具有明显的地带性特征。从西北到东南,随着纬度的逐渐降低,黄土中的粘土矿物组合也发生有规律的变化。主要表现为绿泥石含量的逐渐减少和蛭石含量的逐渐增多。位于温带半干旱区的兰州黄土以伊利石和绿泥石为主要粘土矿物,而位于亚热带湿润区的大港下蜀黄土则以伊利石和蛭石为主要粘土矿物。黄土中含有较多量的绿泥石可作为黄土母质堆积后干冷气候和微弱风化的标志,而蛭石和蛭石/绿泥石混层矿物含量的增加指示了风化强度的增强。因此,黄土粘土矿物组合特征不仅反映物源区古环境信息,而且指示了黄土堆积期后的生物气候环境。 相似文献
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为揭示临夏盆地晚渐新世沉积物的矿物组成对环境气候的指示意义, 利用X射线衍射和扫描电子显微分析方法, 对临夏盆地晚渐新世的沉积物的矿物组成以及坡缕石的矿物学特征进行了深入的研究.结果表明, 沉积物中的坡缕石主要为自生成因, 极少量具有碎屑成因.自生成因的坡缕石呈细长丝状的形态特征, 往往沿片状的伊/蒙混层粘土矿物颗粒的边缘交代、生长;碎屑成因的坡缕石呈平直细纤维状的, 以单颗粒形式产出, 与细小的粘土矿物颗粒混杂, 或叠合在片状粘土矿物颗粒的表面.在临夏盆地晚渐新世沉积物中, 下段岩层中的粘土矿物组合为伊利石、伊/蒙混层粘土和高岭石;中段岩层的为伊利石、伊/蒙混层粘土;而上段岩层则为伊利石、伊/蒙混层粘土和绿泥石, 反映在盆地形成之后, 气候演化经历从湿润→冷干的变化过程.而沉积物中坡缕石的含量自下而上逐渐增多, 其分布特征与粘土矿物组合所反映的气候环境变化趋势相吻合.伊利石和伊/蒙混层粘土普遍存在于临夏盆地晚渐新世沉积物中, 伊利石、伊/蒙混层粘土和高岭石的共存表明这些粘土矿物具有不同的来源.坡缕石是干旱、半干旱地区泥灰岩风化以及风成沙漠尘土沉积物的特征矿物, 临夏盆地晚渐新世的沉积物中碎屑成因坡缕石的发现, 表明自~9Ma以来便出现风成黄土的沉积. 相似文献
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黏土矿物古气候意义研究的现状与展望 总被引：6，自引：1，他引：5
系统地分析了利用海洋沉积物、古土壤、湖盆沉积物中黏土矿物进行古气候环境研究的现状、存在问题和发展趋势。海洋沉积物的物源范围广,影响因素复杂,其中的碎屑黏土矿物所指示的古气候参数只能用于解释母源区的气候变化,而只有自生黏土矿物才能指示沉积区的气候;古土壤形成于特定的地质背景条件下,尤其是发育于火山物质母岩之上的风化自生黏土矿物,可以准确地指示该区的古气候条件;湖盆沉积物的物源范围小,沉积物中的黏土矿物可以更有效地运用于古气候环境的分析。对于沉积物中黏土矿物来源的分析,可以借助晶体中cv空位和tv空位的精细结构特征进行判断;在风化改造的红土剖面研究中,因强烈的化学风化、淋滤和迁移,黏土矿物方法具有独特的优势。风化过程中形成的一些亚种或过渡性黏土矿物,以及同生沉积过程中形成的黏土矿物,对气候环境的变化更加敏感,应加强这方面的研究。此外,在造山带的气候环境演化研究中,自生黏土矿物稳定同位素可以更可靠地指示气候环境的变化。 相似文献
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Concentration of Fe-oxides and alumina in weathering processes are main geological reactions for lateritization and bauxitization, respectively. In western Japan, red-coloured soil formed by weathering processes developed in many places. This soil is composed of hydrous Fe-oxide minerals, hydrous alumina minerals and other minerals. It was formed in the upper part of deep weathering crust by weathering processes under some kind of sub-tropical climate, probably in the Pliocene. One of these occurrences is observed in the upper part of Goshikidai and Konodai, west part of Takamatsu city, northeast Shikoku Island, west Japan. A deep weathering crust is distributed on wide hilly plains ranging from 250 to 400 m a.m.s.l. in the northwestern region of Takamatsu city. Original rock of the weathering crust is bronzite andesite and glassy bronzite andesite, so-called ‘sanukite’. The andesites had been weathered under some special climate, and the geological age of the weathering is the same as above. The mineral assemblage and formation mechanism are similar to those of laterite and bauxite. The weathering crust developing in this region are subdivided into the three following zones: (1) A zone, composed of hydrous Fe-oxides and metahalloysite with small amounts of gibbsite and it is associated with white veins of metahalloysite; (2) B zone, composed of hydrous Fe-oxides and metahalloysite (some material is associated with -cristobalite); and C zone, composed of metahalloysite or halloysite and -cristobalite with relict crystals of feldspar and quartz, and some material is associated with montmorillonite. Chemical analyses of the materials of the three zones show the formation mechanisms of the weathering crust. 相似文献
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Chemical weathering in Luzon, Philippines from clay mineralogy and major-element geochemistry of river sediments 总被引：3，自引：0，他引：3
Zhifei Liu Yulong Zhao Christophe Colin Fernando P. Siringan Qiong Wu 《Applied Geochemistry》2009,24(11):2195-2205
Clay mineralogy and major-element geochemistry of 35 surface sediment samples collected in 21 major to moderate rivers of Luzon, Philippines are used to evaluate the present chemical weathering process. The clay mineral assemblage consists mainly of smectite (average 86%) with minor kaolinite (9%) and chlorite (5%) and very scarce illite (1%), and does not show strong island-wide differences. The major element results of both bulk and clay-fraction sediments indicate that the formation of clay minerals is accompanied by leaching of Ca and Na first and of Fe and Mn thereafter during the chemical weathering process. A low-moderate chemical weathering degree of bulk sediments and a moderate-intensive degree of clay-fraction sediments are obtained in Luzon rivers based on proxies of chemical index of alteration (CIA) and smectite crystallinity. It is suggested that the majority of andesitic–basaltic volcanic and sedimentary rocks along with the tectonically active geological setting and sub-tropical East Asian monsoon climate are responsible for the predominance of smectite in the clay mineral assemblage. 相似文献
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The study of minerals is often focused on their crystallographic properties, chemistry and economic importance, and so their breakdown, or 'weathering'. by physical, chemical and biological processes is less well understood. However, mineral weathering is of considerable environmental significance. The interaction of minerals with water and microbes, such as algae and bacteria, controls soil fertility, the transportation of pollutants through the ground, and ultimately the removal of CO2 from the atmosphere over geological timescales. Therefore, minerals are a key factor in moderating global climate change. This article introduces conventional and new techniques that are being used by geologists to investigate these processes. 相似文献
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Arieh Singer 《Earth》1980,15(4):303-326
The interpretation of paleoclays for paleoclimatic purposes is based on five major assumptions: (1) clay mineral formation is directly related to climatic parameters; (2) once formed in the weathering milieu, clay minerals are stable and do not change any more as long as the climate remains stable (pre-burial stability); (3) clay mineral assemblages are uniform throughout the weathering profile; (4) once formed or deposited and buried, clay minerals are stable (post-burial stability); (5) the sensitivity of clay minerals towards environmental factors is uniform. All these assumptions have only a limited validity. Clay mineral formation is in few cases directly related to climatic parameters, nor do clay minerals always represent the stable end products in equilibrium with environmental factors. The vertical distribution pattern of authigenically formed clay minerals is seldom monomineralic. Post-depositional changes are not infrequent. The sensitivity of clay minerals to environmental factors is variable. The use of paleoclays occurring in paleosols and weathering profiles is reviewed. Paleoclays occurring in paleosols or weathering profiles are, in well-defined situations, suitable for paleoclimatic interpretation. At our present state of knowledge, references as to the nature of climates of the past that are based solely on the interpretation of paleoclays are warranted only in exceptional cases. Authigenic occurrences of clay minerals with limited stability fields that can be used as ‘marker minerals’ and the isotopic composition of paleoclay minerals promise, with future research, to increase the value of paleoclays as paleoclimatic indicators. 相似文献
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风化作用是源-汇沉积体系中的重要环节,气候、构造、地形、植被和岩性在不同程度上控制着地表硅酸盐化学风化,量化硅酸盐化学风化强度有助于开展全球性的实例研究对比。本研究归纳总结了基于碎屑沉积物的化学风化强度指标,包括岩石学和矿物学指标、元素地球化学指标和非传统稳定同位素指标,并指出了指标在应用中存在的问题。这些指标中:砂质沉积物骨架颗粒组成、粉砂级碎屑的矿物组成和矿物表面结构特征从矿物组成和结构上直观地反映了化学风化强度,运用不多但值得关注;黏土矿物组合和主微量元素指标如CIA、Rb/Sr、αAlE等在实例研究中运用广泛,同时也显现出易受物源和水动力分选影响等弊端;新近开发的利用锂、硼、钾、镁、硅等同位素示踪化学风化强度的方法具有广阔的应用前景,同位素的分馏机理有待完善。源-汇体系中的其他过程如物源供给、水动力分选、成岩作用、再旋回作用、成土作用、物理淋滤和生物利用等会影响化学风化指标的使用效果,通过多指标的综合运用和相互验证,可以有效提升化学风化强度评估的准确性。 相似文献
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Koji Wada 《Chemical Geology》1987,60(1-4):17-28
Weathering of volcanic ash and pumice is unique regarding minerals formed and mineral formation. These minerals include allophane, imogolite, opaline silica and some halloysites, and have distinctive structures and properties. Studies on the surface and subsurface weathering of various volcanic ashes in different settings are reviewed. This review illustrates that relatively rapid weathering of finely comminuted volcanic ash well reflects the effects of climate, vegetation and time, and produces various combinations of weathering products. The moisture regime, the nature and amount of organic matter incorporated, the deposition of volcanic ash as overburden, and the chemical and mineralogical composition of parent ash are important in controlling the mineral formation in weathered volcanic ash. 相似文献
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火星次生含水蚀变矿物是火星地质历史时期水环境和气候演变历史的真实记录,一直以来都是火星探测、火星陨石研究的重点,是认识火星环境特征和气候演化的重要研究对象。文中对比研究了表土角砾岩NWA7034、火成堆晶岩MIL03346等两块最富蚀变矿物火星陨石,以及Gale撞击坑出露的Sheepbed泥岩3种岩石类型的蚀变程度及其蚀变矿物类型和组合,分析了层状硅酸盐、铁氧化物/氢氧化物、钙硫酸盐等蚀变矿物的成因及环境指示意义。发现这3类岩石的蚀变作用各不相同。火星陨石NWA7034的蚀变作用以氧化和加热作用为主,无蒸发盐类矿物。火星陨石MIL03346的蚀变程度最低,为后期水溶液进入缝隙而引发的,蚀变作用以橄榄石的伊利石化、裂隙和缝隙中填充次生矿物细脉为主。而火星Sheepbed泥岩经历了后期的等化学风化过程(isochemical weathering),次生过程包括成岩蚀变和成岩后蚀变两个阶段。其中,成岩过程中的蚀变以橄榄石蚀变为铁氧化物和蒙皂石矿物为主,成岩后以形成蒸发盐类矿物硫酸钙为主。以上3种岩石蚀变矿物组成差异反映了火星上不同地质背景中、不同气候条件下蚀变过程的复杂性。文中对火星含水矿物及部分典型矿物的形成条件和过程进行系统总结,这对于理解未来火星探测任务、识别含水矿物的形成、揭示火星水环境和地质历史具有重要指导意义。 相似文献