共查询到18条相似文献，搜索用时 125 毫秒
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以蒙脱石为初始材料,通过水热实验模拟在不同温度压力条件下蒙脱石的伊利石化过程。利用X射线粉末衍射及X射线荧光光谱、红外光谱和扫描电镜等方法对样品的矿物物相、化学成分、晶体结构与微观形貌等进行分析,其结果表明:(1)蒙脱石至伊利石的转化受温度和压力条件的控制;(2)随着温度和压力的增高,蒙脱石伊利石化沿着蒙脱石-无序伊蒙混层-有序伊蒙混层-伊利石的转化序列进行转化;(3)水热实验模拟表明蒙脱石至伊利石的转化以溶解重结晶机制为主。实验结果不仅有助于了解埋藏与低级变质作用中的蒙脱石伊利石化过程,同时为研究断层活动所致断层泥中黏土矿物的转化及反演断层形成时温度压力条件提供基本参数。 相似文献
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广西东攀剖面二叠系顶部粘土矿物特征及古气候意义 总被引：2，自引：1，他引：1
对广西东攀剖面二叠系顶部20个样品中的粘土矿物进行X射线衍射分析。伊利石结晶度值显示这些样品形成于中晚成岩带的地质环境;伊利石、蒙脱石纵向分布规律和伊利石结晶度与伊利石含量的关系表明伊利石除陆源碎屑来源外,可能有部分为蒙脱石伊利石化而成;伊利石结晶度变化曲线和伊蒙混层类型的变化规律表明,本区粘土矿物组合与含量的变化除受到后期成岩作用的影响外,还明显地受沉积因素的控制;伊利石结晶度、伊利石化学指数、高岭石和伊利石的含量、伊蒙混层类型显示东攀剖面以9、10层界线上方5cm为界,古气候由干冷变为湿暖;水介质由偏碱性向酸性转变。 相似文献
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《矿物学报》2017,(Z1)
石英胶结作用是导致砂岩储层致密的重要原因之一,目前关于石英胶结物SiO_2内部或外部来源尚无定论。关于石英胶结物SiO_2来源问题的研究较薄弱,尤其对非晶质SiO_2溶解来源和SiO_2外部来源的研究重视不足。本文在前人研究成果的基础上,重点探讨了致密砂岩储层中石英胶结物形成的成岩作用时间及SiO_2的物质来源,并研究了其贡献量的大小。结果表明:(1)长石的溶解与转化、蒙脱石的伊利石化和绿泥石化作用、压溶作用与缝合线的发育,以及非晶质SiO_2的溶解作用,是砂岩储层中石英胶结物发育的重要内部SiO_2来源。石英胶结物的外部来源则包括岩石邻近的砂体,也包括深部埋藏砂岩、深部埋藏泥岩、花岗岩侵入体、基岩等来源的大规模运移。(2)长石的溶解、蒙脱石的伊利石化和绿泥石化作用、压溶作用与缝合线的发育,主要在早成岩-中成岩时期为砂岩储层提供SiO_2来源,而钾长石向高岭石和伊利石的转化、钠长石化作用主要为中成岩-晚成岩时期石英胶结物的主要SiO_2来源。此外,非晶质SiO_2的溶解和外部来源提供的SiO_2推测应该可以发生在整个沉积成岩时期,且需要进一步研究工作验证。 相似文献
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在浙江长兴煤山全球二叠系一三叠系界线层型剖面中界线附近采集黏土岩样品。对其中的伊利石／蒙皂石成岩间层I／S进行K—Ar测年实验研究，来探讨沉积岩中自生伊利石K—Ar测年在确定沉积地层时代方面的可行性。结果表明，沉积岩中成岩间层I／S的K—Ar年龄在没有碎屑含钾矿物混入的情况下，比其对应的地层时代要年轻，其原因主要有两条，一是因为泥岩中的自生伊利石来自于蒙皂石的伊利石化，而蒙皂石的伊利石化受很多因素控制，需要一定的时间才能完成；另一原因是由于蒙皂石伊利石化过程中存在着放射性成因^40Ar的扩散丢失。 相似文献
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通过研究无烟煤层中泥岩夹矸的岩石矿物学特征,探讨了其主要成分高岭石发生转化的主要方向及影响因素。通过样品的显微镜下鉴定、差热分析、X射线粉晶衍射分析、红外吸收光谱分析等一系列测试结果的分析研究,发现无烟煤层泥岩夹矸中高岭石因受不同因素的影响而发生不同的转化,即:高岭石向伊利石转化,伊利石-蒙脱石(I/M)混层矿物及蒙脱石出现。其主要原因是区域变质作用及周围介质影响所致。 相似文献
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蒙脱石伊利石化对含油气盆地地层压力影响的定量研究 总被引：1，自引：0，他引：1
异常高压带是含油气系统研究和资源勘探领域的热点之一。本文以东营凹陷为例，定量研究了牯土矿物成岩作用对地层压力聚集的贡献。在系统分析粘土矿物组成、成岩物理化学条件的基础上，模拟计算了蒙脱石伊利石化的动力学过程，计算了脱水造成的体积变化和硅钙释放量。指出脱水作用造成的体积变化不是形成异常高压的重要因素，但硅钙的释放可能对封隔层的形成起着非常关键的作用，对地层异常压力的积聚和保持有重要贡献。 相似文献
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海绿石是一种浅海相沉积指示矿物,形成成熟的海绿石需1Ma。本文以含铁量很低的蒙脱石和0.1mol/LFe~(3+)、0.2mol/LK~+的离子溶液分别为初始物质在50℃恒温环境和不同的pH、Eh条件下,模拟海绿石化过程,并通过XRD、FTIR、SEM、ESR等检测反应产物。研究发现,在SEM下观察到球形纳米颗粒的海绿石出现;同时XRD谱图上除出现云母类矿物的001衍射峰外,还出现d值为0.1520nm和0.1498nm的代表海绿石和铁伊利石的060特征衍射峰。pH和氧化还原条件对产物的影响比较显著,pH为酸性时出现海绿石和铁伊利石的组合,其红外吸收谱中出现AlFe~(2+)OH或Mg~(2+)Fe~(3+)OH(3547~3562cm~(-1))、Fe~(3+)Fe~(3+)OH的伸缩振动峰,与之相应的ESR中出现g=1.978的八面体位Fe~(3+)的共振峰;当pH介于中性的时候,红外光谱谱图上出现明显的AlFe~(2+)OH、Mg~(2+)Fe~(3+)OH(3550~3562cm~(-1))和Al~(3+)Fe~(3+)OH(870cm~(-1))振动;pH为碱性时,出现Fe~(3+)Mg~(2+)OH(3560cm~(-1))振动;上述红外吸收振动的出现表明Fe~(3+)已经进入了蒙脱石结构的八面体位。蒙脱石在上述条件下发生明显的改变,发生海绿石化或铁伊利石化,pH和氧化还原条件对结果的影响比较显著,酸性的环境中海绿石化显著,而中性至碱性的环境则发生铁伊利石化。 相似文献
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蒙皂石伊利石化的三种成因机制 总被引：1，自引：0，他引：1
蒙皂石伊利石化的三种成因机制张立飞（北京大学地质学系，１００８７１）蒙皂石的伊利石化（ｉｌｌｉｔｉｚａｔｉｏｎ）是粘土矿物在沉积成岩阶段或进入很低温变质阶段所发生的最常见的一种反应过程。其研究对于探讨成岩作用过程和石油的形成、运移都有重要意义。但有关... 相似文献
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Javier Cuadros 《Geochimica et cosmochimica acta》2006,70(16):4181-4195
The kinetics of smectite illitization in shale samples from eight wells have been modeled using the equation −dS/dt = kK0.25S5 [Cuadros, J., Linares J., 1996. Experimental kinetic study of the smectite-to-illite transformation. Geochim. Cosmochim. Acta60, 439-453], where S is the proportion of smectite layers in illite-smectite (I-S), t is time, k is the rate constant and K is the concentration of potassium. The I-S compositions and the physical parameters were obtained from the literature. Potassium concentration is the only unknown parameter and it was chosen to fit the experimental data. I propose that this variable is termed “effective K concentration,” as it is affected not by the actual K concentration alone but also by those of other cations that compete with K for the smectite interlayer sites, especially Ca, by ion mobility in the sediments and possibly by other variables. The kinetic equation allows an accurate fit to the experimental data in all the wells, reproducing both the illitization onset and the patterns of the plots of % smectite vs. depth. The relative changes of the values of “effective K concentration” compare well with K/Ca equivalent ratios in the whole rock. Three of the modeled wells, located in near proximity, produced similar “effective K concentration” patterns. These results support the validity of the equation used in the models. They also suggest that this equation can be used to assess K concentrations in sediments and K mobility within basins. 相似文献
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下扬子区早三叠世风暴沉积的粘土矿物分析 总被引：1，自引：0，他引：1
通过对下扬子区泾县、宁国、宜兴等地早三叠世风暴沉积中的粘土矿物进行取样分析,并综合沉积学和古生物学等特征的研究表明：随着Kübler指数的增高,所测样品中蒙皂石的含量呈递减趋势,蒙皂石伊利石化明显受阻,并且风暴沉积的各层段粘土矿物组合特征也相差较大,其主要因素是物源的变化。根据沉积特征和粘土矿物组合中蒙皂石和伊利石等含量的不同,可将本次研究的剖面分为两个序列:序列Ⅰ以宁国和宜兴等地为代表,为近源型风暴沉积;序列Ⅱ以泾县为代表,出现了近源和远源的双重属性,究其原因可能是因泾县位于近源和远源沉积的过渡带所致。 相似文献
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There is convincing evidence from field data that smectite clay undergoes conversion primarily to illite and chlorite if it is fully water-saturated and heated. The conversion may take place through mixed-layer formation with increasing illite/smectite ratio at higher temperatures and pressures. This process requires dehydration of the interlamellar space, for which either an external pressure or drying are needed. An alternative mechanism that takes place without dehydration, is dissolution of smectite and neoformation of illite. Both processes imply reorganization of the smectite crystal lattice for which the activation energy is fairly high, meaning that the conversion is negligible at temperatures lower than about 60°C. At elevated temperatures the conversion rate is controlled by the access to potassium for either mechanism.
An ongoing detailed investigation of this subject has led to a tentative model for the smectite-to-illite conversion in natural sediments and in canister-embedding clay in high-level radioactive waste (HLW) repositories. 相似文献
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超压背景下粘土矿物转化的化学动力学模型及应用 总被引：14，自引：4，他引：10
在目前的粘土矿物转化化学动力学模型中,人们仅考虑了温度、时间和流体介质的影响。然而新近的一些研究表明,超压可以抑制粘土矿物的转化,增加反应活化能。通过超压调节反应活化能,建立超压背景下粘土矿物转化的化学动力学模型,并根据渤海湾盆地板桥凹陷、歧北凹陷超压发育井和歧南凹陷超压不发育井的粘土矿物实测资料,确定了相关参数。模拟结果表明,在超压井中,伊/蒙混层中蒙皂石层含量S%的计算值与实测数据吻合较好,但与Pytter和Reynolds(1989)模型的预测结果相差甚远,在压力系数为1.2~1.7的地层中,超压对S%的抑制最大可达15%~20%。由于在蒙皂石向伊利石转化的过程中,释放出大量S i4+、Ca2+、Mg2+、Fe3+、Na+等阳离子,所以超压对粘土矿物转化的抑制,导致了泥岩中这些阳离子生成量的减少和相邻砂岩中许多胶结作用的延迟,这非常有利于深层(埋深>3 500 m)优质储层的发育和油气藏的形成。 相似文献
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蒙皂石—伊利石演化及有关问题的理论探讨 总被引：2，自引：1，他引：1
摘要：作者认为蒙皂石—伊利石的转化是多因素、多机制作用的结果．不同环境、不同机制形成的伊／蒙混层矿物,有序化出现时的伊利石层含量不同。伊／蒙混层由无序到有序是一个连续的渐变过程,存在过渡型混层矿物,多数伊／蒙混层矿物都是以某一类型为主的复杂集合体。作者指出分散蒙皂石是影响无序型伊／蒙混层矿物混层比计算精度的主要因素。 相似文献
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《矿物学报》2013,(Z1)
The clay mineralogy of the clay intervals interbedded with siliceous mudstones across the Permian-Triassic boundary (PTB) in Pengda, Guiyang, Guizhou province, was investigated by X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). The clay mineral assemblages of the sediments are mainly I/S clays and minor smectite, kaolinite, and illite as reveled by XRD analyses. The peak-shape parameters BB1 and BB2 of I/S clays of the representative clay bed PL-01 are 4.7° and 4.4°, and the peak position of the low angle reflection is at 6.8° 2θ (13.6 ), suggesting that the I/S clays has a IS type of ordering. However, the presence of multi-order reflections and their intensities are different from those of completely ordered 1∶1 mixed-layer I/S clay rectorite, indicating that I/S clays of the Pengda section have partially ordered IS structures. HRTEM observations show that most of the I/S clays exhibit an IS stacking ordering. However, in some areas within a IS particle, smectite layer is observed in doublets, triplets, and quartets, which are interstratified by various amounts of illite layers, suggesting the presence of other irregular stacking in addition to the major 1∶1 IS ordered stacking. Transformation of smectite layer into illite layers is also observed in the I/S clays, suggesting that the Pengda I/S clays are derived from smectite illitization, in good agreement with the clay mineral assemblage. The I/S clays of the Pengda section contain up to 45% to 95% smectite layer, the notably higher contents of smectite layer relative to those of other PTB stratigraphic sets in south China can be attributed to difference in alteration and smectite illitization processes due to different sedimentary environments. 相似文献
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《矿物学报》2013,(Z1)
Clay minerals are ubiquitous on epigeosphere, especially in soils and sediments where microbes thrive. The clay-microbe interactions are common in these geological media and greatly contribute to accelerating the mineral transformation process, e.g. the illitization of nontronite (a Fe-rich smectite) catalyzed by microbes under anoxic atmosphere in 2 weeks. However, few has considered montmorillonite, a Fe-poor smectite more typical in natural environments than nontronite. This study therefore focuses on the interaction between montmorillonite and bacteria under conditions relevant to those in natural soils and sediments. 相似文献
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W. Crawford Elliott Stephen G. Osborn Vanessa J. O'Brien R. Douglas Elmore Michael H. Engel J. Marion Wampler 《Journal of Geochemical Exploration》2006,89(1-3):92
In this study, we test a burial model for diagenetic illite and whether illitization is related to the acquisition of a chemical remanent magnetization (CRM). A prefolding, reversed polarity, secondary magnetization is found in carbonate concretions in diagenetically altered Upper Cretaceous rocks in the disturbed belt of Montana. Stratigraphically equivalent unaltered rocks to the east do not contain the magnetization. The magnetization could be a CRM or a thermoviscous remagnetization. The pole position is generally consistent with the Early Tertiary K–Ar ages of diagenetic illite–smectite formed under thrust loading, but it is not constrained well enough for a precise age comparison. If this magnetization is a CRM, it could be related to illitization. Alternatively, if the prefolding CRM had been acquired prior to thrust loading then the magnetization is not related to illitization. Geochemical studies are currently underway to test if the magnetization could be related to fluid alteration. 相似文献