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1.
《Applied Geochemistry》2005,20(1):89-99
The reaction of the clay fraction of the Callovo–Oxfordian hard shale formation hosting the French underground laboratory site, with high pH NaOH, KOH and Ca(OH)2 solutions has been investigated through closed system experiments at 60, 90 and 120 °C over 6, 24 and 168 h. The mineralogical composition of the run samples has been determined using X-ray diffraction (XRD) of randomly oriented powders showing the formation of different species of zeolites (analcime, chabazite, phillipsite) and Ca silicates (tobermorite, katoite). The phyllosilicates were studied using XRD of oriented preparations and cation exchange capacity measurements. Detrital or diagenetic mica and chlorite in the <2 μm fraction remain unchanged. On the contrary, the smectite and random illite–smectite mixed layer minerals are strongly reactive. The expandable layers of montmorillonite type are selectively dissolved while beidellitic ones survive or are transitionally formed. 相似文献
2.
Ulrike Wirsching 《Contributions to Mineralogy and Petrology》1975,49(2):117-124
In the formation of zeolites by hydrothermal alteration volcanic glasses are the starting material in most cases. The experiments aimed at demonstrating in what way the chemistry of the volcanic glass influences:
- the alteration rate of the volcanic glass to zeolites,
- the kind of zeolites being formed and their formation conditions.
3.
Experimente zur Zeolithbildung durch hydrothermale Umwandlung 总被引：1，自引：0，他引：1
Helmut Höller Ulrike Wirsching Mahmud Fakhuri 《Contributions to Mineralogy and Petrology》1974,46(1):49-60
The formation of zeolites by hydrothermal alteration has been investigated by taking trass from the Laach volcanic area as a sample. Zeolites to be found are chabazite, phillipsite and analcime, all of which originated from the same phonolitic glass. This paper aims at explaining the formation of zeolites by means of experimental alteration of the pumice with various solutions. NaOH and KOH solutions were used in the experiments, these limited the formation conditions of chabazite, phillipsite, analcime in alkaline environments. Moreover, experiments were carried out with H2O dist and with solutions that formed during the alteration of pumice by reacting with H2O. These experiments were conducted to supply clues concerning the formation of zeolites in the Laach volcanic area. With NaOH solutions zeolites were formed from pumice within a temperature range of 70 to 250° C and a concentration range of 0.001 to 1.0 n; with KOH solutions they were formed in the same concentration range within a temperature range of 100 to 250° C. The formation of zeolites proved to depend much on temperature and concentration: At low temperatures high concentrations are necessary, higher temperatures need lower concentrations. With NaOH solutions the zeolites are formed in the succession, chabazite, phillipsite, analcime at increasing temperatures and increasing concentrations. With KOH solutions the same succession is to be found with rising temperature. With rising concentration, however, this succession is changed at higher temperatures: Phillipsite appears in place of analcime at high temperatures and concentrations. By the alteration of pumice with H2O, zeolites are formed from 200° C onward. With solutions that had been formed during the alteration of pumice by reacting with H2O, the minimum temperature for the formation of zeolites was 180° C. Concerning the genesis of zeolites in the Laach volcanic area, the experiments showed that the temperature for the formation of analcime was about 250° C; for the formation of chabazite and phillipsite it was between 150 and 190° C. The pH of the reacting solutions may have been between 7 and 8. Thus the experiments proved that from the same material different zeolites, chabazite, phillipsite, analcime may be formed by temperature change of the reacting solutions (H2O to slightly alkaline solutions). 相似文献
4.
Trace element concentrations of altered basaltic glass shards (layer silicates) and zeolites in volcaniclastic sediments drilled in the volcanic apron northeast of Gran Canaria during Ocean Drilling Program (ODP) leg 157 document variable element mobilities during low-temperature alteration processes in a marine environment. Clay minerals (saponite, montmorillonite, smectite) replacing volcanic glass particles are enriched in transition metals and rare earth elements (REE). The degree of retention of REE within the alteration products of the basaltic glass is correlated with the field strength of the cations. The high field-strength elements are preferentially retained or enriched in the alteration products by sorption through clay minerals. Most trace elements are enriched in a boundary layer close to the interface mineral-altered glass. This boundary layer has a key function for the physico-chemical conditions of the subsequent alteration process by providing a large reactive surface and by lowering the fluid permeability. The release of most elements is buffered by incorporation into secondary precipitates (sodium-rich zeolites, phillipsite, Fe- and Mn-oxides) as shown by calculated distribution coefficients between altered glasses and authigenic minerals. Chemical fluxes change from an open to a closed system behavior during prograde low-temperature alteration of volcaniclastic sediments with no significant trace metal flux from the sediment to the water column. 相似文献
5.
The Upper Red Formation (URF) comprises over 1–5 km of late Miocene siliciclastic sediments in the Central Iran Basin. The formation is dominated by volcaniclastic conglomerates and arenites. The prevailing arid conditions during most of the basin's history resulted in deposition of predominantly organic‐poor, red sediments with gypsum and zeolites. This investigation concentrates on the mineralogy and geochemistry of the URF in the southern and northern margins of the basin where the formation was buried to depths of 2.4 and 6.6 km, respectively. Fine fraction mineral separates from the southern margin consist of nearly pure smectite and zeolites at a depth of 400 m and smectite with minor quartz and calcite at 1800 m. Shallow samples (1350 m) from the northern section are rich in smectite, illite/smectite with some discrete illite and chlorite. This assemblage is progressively replaced by discrete illite and chlorite with increasing burial depth so that only these two minerals are found at depths greater than 4300 m. The initial alteration process involved replacement of glass and volcanic lithics by smectite and zeolites in both margins of the basin. Increased depth of burial in the northern margin resulted in the progressive isochemical alteration of smectite to discrete illite and chlorite. Diagenesis of clay assemblages occurred essentially in a closed system. Solute products of glass hydrolysis reactions were retained in highly alkaline, saline ground waters from which zeolites, carbonates and oxides precipitated as cements. It is unlikely that these sediments were ever significantly leached by meteoric waters or by organic acids generated during burial diagenesis. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
6.
The Bigadiç, Emet and Kirka lacustrine basins of western Turkey may be considered as Tibet-type graben structures that were developed during the Miocene within the Izmir-Ankara suture zone complex. The volcanic-sedimentary successions of these basins are made up of mudstone, carbonate (limestone and dolomite) and detrital rocks, and also of crystal or vitric tuffs about 135 to 200 m thick. The Degirmenli (Bigadiç), Emirler (Bigadiç) Köpenez (Emet) and Karaören (Kirka) tuffs constituting the zeolite deposits are situated beneath four borate deposits (colemanite, ulexite, borax). The most abundant diagenetic silicate minerals are K- and Ca-clinoptilolites in the zeolite deposits, and Li-rich trioctahedral smectites (stevensite, saponite and hectorite) and K-feldspar in the borate deposits. In the Degirmenli, Emirler. Köpenez and Karaören deposits, the following diagenetic faciès were developed from rhyolitic glasses rich in K and poor in Na: (glass + smectite), (K-clinoptilolite + opal-CT), (Caclinoptilolite + K-feldspar ± analcime ± quartz) and (K-feldspar+analcime+quartz). K-feldspar which is also rarely associated with phillipsite (Karaören) and heulandite (Degirmenli and Karaören), succeeds clinoptilolite and precedes analcime in these diagenetic facies where dioctahedral smectites, opal-CT and quartz are the latest minerals. No diagenetic transformations exist between clinoptilolite, K-feldspar and analcime that were formed directly from glass. The lateral facies distributions resulted from the differences in salinity and pH of pore water trapped during deposition of the tuffs, but vertical distributions in vitric tuffs seem to have been controlled by the glass/liquid ratio of the reacting system and the permeability or diffusion rate of alkali elements. The Bigadiç, Emet and Kirka zeolite deposits which were formed in saline basins rich in Ca and Mg ions, show similar chemical changes, i.e. loss of alkalis and gain in alkaline-earth elements that have taken place during the diagenetic transformation of rhyolitic glasses to dioctahedral smectites or clinoptilolite. The absence of sodic zeolites such as mordenite, erionite, chabazite and silica-rich phillipsite is mainly due to the very high K/Na ratio of the starting materials rather than initial alkaline conditions or high Na content in lake waters. 相似文献
7.
Fresh mid-ocean ridge basalt of varying crystallinity has been powdered and reacted with seawater and an artificial Na-K-Ca-Cl solution at 200–500°C and 500–1000 bar in sealed gold capsules. Water/rock mass ratios of 1–3 were used and durations ranged from 2 to 20 months.These time periods were sufficient for most elements to approach a steady-state concentration in solution which was determined by equilibrium with alteration minerals (Mg, SiO2, SO4), by rate of formation of these minerals (Na, Ca), or by depletion from the rock (K, B, Ba). The resulting solutions closely resemble the brines from the basalt-seawater geothermal system at Reykjanes, Iceland. Mg was almost completely removed from seawater into the alteration products smectite, tremolite-actinolite, or talc. Sulfate also was removed to low concentrations, both by precipitation of anyhydrite and by reduction to sulfide. Net transfer of Na from seawater into solids occurred in most experiments by formation of sodic feldspar and possibly analcime. Sr was removed from seawater in some experiments but showed no change or a small gain in others. SiO2, Ca, K, Ba, B and CO2 were leached from basalt and enriched in solution. SiO2 concentrations were controlled by saturation with quartz at 300°C and above. The principal Ca-bearing phases which formed were anhydrite, the hydrated Ca-silicate truscottite, tremolite-actinolite, and possibly wairakite. No K-rich phases formed. For some minerals the crystallinity of the starting basalt affected the amount which formed.Removal of Mg from seawater into solid alteration products occurred rapidly and was balanced largely by leaching of Ca from basalt. Net transfer of Na from seawater into solids occurred more slowly and was balanced mainly by leaching of additional Ca from basalt. Thus, reaction between seawater and basalt at low water/rock ratios can be considered to consist of two exchanges: Mg for Ca, and Na for Ca. 相似文献
8.
In the Deer Lake Basin of western Newfoundland, Canada, analcime has been found within fine-grained, siliciclastic and carbonate, lake and lake-margin sediments of the Carboniferous Rocky Brook Formation. Analcime is the only zeolite observed in these unmetamorphosed and non-volcanogenic rocks. Microscopic analcime occurs as vug-filling, limpid, isotropic to anisotropic crystals. Microprobe analyses show this type of analcime to be lower in silica than most analcime in sedimentary rocks. A second textural type of finer-grained submicroscopic analcime can be detected from X-ray diffraction spectra of Rocky Brook Formation mudstones, where it is associated with phyllosilicates (illite, interstratified chlorite/smectite, smectite, chlorite), other silicates (quartz, feldspar) and carbonates (dolomite, calcite). Results of this study suggest that the analcime in the Rocky Brook Formation formed either by direct lakewater/porewater precipitation or by reaction of these waters with one or more clay mineral types or plagioclase. 相似文献
9.
Zeolitic diagenesis of late Quaternary fluviolacustrine sediments and associated calcrete formation in the Lake Bogoria Basin, Kenya Rift Valley 总被引：1，自引：0，他引：1
R. W. RENAUT 《Sedimentology》1993,40(2):271-301
Late Quaternary fluviolacustrine siltstones, mudstones and claystones (Loboi Silts) on the northern margins of the saline, alkaline Lake Bogoria in the Kenya Rift Valley contain up to c. 40% authigenic analcime and minor natrolite. The zeolitic sediments are reddish brown and up to 1 m thick. The amount of analcime increases upward in the profile, but decreases with distance from the lake. The altered sediments show many pedogenic features including zeolitic root mats, rootmarks, concretions and carbonate rhizoliths. Residual patches of calcrete locally cap the zeolitic rocks. The profile is interpreted as an exhumed palaeosol and land surface on the former margins of the lake. The analcime occurs as submicroscopic (0–5–2–5 μ.m) subhedral and euhedral crystals, which have an average Si/A 1 ratio of 2–33 (as determined by X-ray microanalysis) or 2–18 (d-value of 639 analcime peak). The analcime formed in lake marginal sediments (soils) by reaction of silicate detritus with Na2CO3 rich pore waters concentrated close to the land surface by evaporative pumping and evapotranspiration. Poorly ordered clay minerals were probably the main reactants. Authigenic illite may have been a by-product of the reactions. Chemical analyses suggest that pore waters supplied some of Na+, and possibly K+ and SiO2. The associated calcrete and rhizoliths were formed during or shortly after the main period of zeolitic alteration. The Ca2+ may have originated from infiltrating dilute runoff and groundwater. Authigenic smectite was precipitated in open porosity following analcime formation. The zeolitic alteration at Lake Bogoria provides a relatively recent analogue for lake marginal zeolites found in many ancient saline, alkaline lake sediments. 相似文献
10.
Jung Ho Ahn Donald R. Peacor Douglas S. Coombs 《Contributions to Mineralogy and Petrology》1988,99(1):82-89
Clay minerals from the three principal kinds of zeolitic sediments from the type area for zeolite facies alteration, the Triassic Murihiku Supergroup, Southland, New Zealand, have been studied by TEM. Bentonitic tuff consists largely of smectite and heulandite with minor illite; they occur as replacements of glass shards and are inferred to be direct alteration products of tuff alteration. Both analcime- and laumontite-rich tuffs contain chlorite, illite and mixed-layer illite-chlorite, including 11 mixed-layer sequences. Subhedral to euhedral phyllosilicate crystal shapes and other textural features imply that phyllosilicates crystallized from solution derived in part by dissolution of precursor smectite. Intralayer transitions involving illite and chlorite are inferred to be products of crystallization rather than direct alteration and replacement. Petrographically similar bentonitic and analcimized tuffs overlap each other in the stratigraphic section, supporting earlier observations that there is no systematic change in smectite relative to the illite plus chlorite derived from smectite in sections up to 8.5 km thick. The data imply that smectite may be metastable relative to illite plus chlorite. Permeability and fluid chemistry are inferred to be as significant as temperature in promoting reactions in clay minerals as well as zeolites during burial metamorphism.Contribution No. 436, from The Mineralogical Laboratory, Department of Geological Sciences, The University of Michigan, Ann Arbor, Michigan 48109 相似文献
11.
松辽盆地晚白垩世地层是由一套砂泥岩组成,储集了丰富的石油资源。过去一般认为这是一个内陆湖泊,为陆相沉积。近年来不少研究者从古生物、岩矿等方面提出与海有关的成因观点。本文根据对该区上白垩统泥岩粘土矿物进行了研究后认为,晚白垩世松辽盆地是个近海陆盆,气候温暖干燥,间转湿润,以淡水-半咸水碱性介质为主,青山口组及嫩江组沉积时,水域扩大,水体含盐度、碱性、还原性增强,可能遭受海侵。这些分析对含油地层的成因研究具有一定的意义。 相似文献
12.
Hiroyuki MAEDA 《Resource Geology》1998,48(2):105-116
Abstract: Characterization of Neogene magmatism in the Ryuo mine area in the Kitami metallogenic province was carried out on the basis of K-Ar data for felsic–to–mafic terrestrial extrusive and intrusive volcanism from Late Miocene to Early Pliocene. The Ryuo epithermal gold-silver deposit occurs primarily in the felsic volcaniclastic rocks of the Ikutahara Formation and in Ryuo Rhyolite. The Ryuo mineralization age of 7. 7 – 8. 1 Ma coincides well with the hydrothermal alteration age (7. 7 Ma) of Ryuo Rhyolite hosting ore veins. It is concluded that the Ryuo mineralization was essentially accompanied by felsic volcanic activity during the sedimentation of the Ikutahara Formation, and was closely related both temporally and spatially to the intrusive activity of Ryuo Rhyolite. Hydrothermal alteration related to the epithermal gold-silver mineralization of the Ryuo deposit is primarily characterized by early regional and vein-related alterations, and late steam-heated alteration. Early regional alteration consists of a smectite halo (smectite+pyrite±quartz±opal–CT±mordenite°Clinoptilolite–heulandite series mineral). Early vein-related alteration is primarily marked by potassic alteration. This alteration halo can be subdivided into a K-feldspar halo (quartz+adular–ia+pyrite±illite±interstratified illite/smectite±smectite), an illite halo (quartz+illite + chlorite + pyrite ± interstratified illite/smec–tite±smectite) and an interstratified illite/smectite halo (quartz + interstratified illite/smectite+pyrite±smectite). Late steam-heated alteration characterized by kaolinite or alunite locally overprints the early K-feldspar halo. The style of the Ryuo gold-silver deposit is a low-sulfidation epithermal type. The gold–silver–bearing quartz vein precipitates during boiling of ore fluid. The origin of the ore fluid might be meteoric water. The temperature and sulfur fugacity conditions during precipitation of electrum and acanthite are estimated to be 206°– 238°C and 10-13.5 – 10-11.6 atm, respectively. 相似文献
13.
Part I: Chemical and structural effects of cation-exchange
Attempts were made to prepare, by appropriate exchange methods, homoionic samples of phillipsite, gismondite, harmotome, chabazite
and gmelinite containing Ba, Ca, K, Na or Li-ions. Powdered natural samples were used as starting material. All samples were
analysed chemically before and after the cation exchange. The results of the analyses demonstrated clearly that the „exchange
capacity“ depends on the method used, the structure of the zeolite and the nature of the cation involved in the exchange.
The analyses also disclosed the important fact that the ratio in Mole % of the sum of exchangeable cations: Al2O3 of the natural and of the exchanged samples is generally <1, and can be as low as 0.74. Examples are presented where cation
exchange results in a substantial change in the framework structure.
Part II: Dehydration behavior and structural changes at elevated temperatures
Samples of the natural zeolites mentioned above, and of some of their cation exchange products were dehydrated in air of controlled
humidity up to 600° C. The slopes of the weight loss curves of chabazite and gmelinite are continuous, whereas those of phillipsite,
gismondite, and harmotome show a discontinuity between 90–190° C, indicating the existence of two discrete hydrated phases
for each of these zeolites. High temperature x-ray studies of powdered samples confirmed this result. The high temperature
hydrates of phillipsite, gismondite, and harmotome persist reversibly up to approximately 230° C. At higher temperatures,
new probably anhydrous phases form. Gmelinite, at 240° C, transforms irreversibly to anhydrous gmelinite which is stable up
to >700° C. The transition was studied by single crystal techniques. The chabazite structure remains intact up to >700° C.
The absolute water content and the dehydration behavoir of the zeolites investigated are primarily dependent on the nature
of the exchange cation. The structural changes at elevated temperatures are determined by the silica alumina framework.
Part III: Hydrothermal stability* and interconversions
The stability of phillipsite, gismondite, harmotome, chabazite, gmelinite, their exchange products, and of the synthetic Linde
zeolites Faujasite and Type A was studied in the temperature range between 150° and 350° C at a constant pressure of 1000
atm of H2O. Between 180° and 260° C all examined Sodium and Calcium zeolites were metastable with respect to analcite (wairakite**).
Phillipsite and sodium-rich zeolites generally converted to analcite (wairakite) directly. Caex-chabazite and Caex-gmelinite formed phillipsite, whereas Ca-gismondite and Ca-Type A formed natrolite as intermediate phases. Li-gmelinite converted
to bikitaite***. (This represents the first successful preparation of natrolite and bikitaite. Attempts starting from gels
or glasses have been unsuccessful so far.) Ba-gmelinite converted to harmotome at 250° C. This transformation was studied
microscopically and by single crystal x-ray techniques.
The transformations that take place on hydrothermal treatment as well as on low temperature cation exchange of zeolites (see
Part I) indicate that, unlike the conditions prevailing in clays, the type of cation and the ratio of cations in the exchange
positions have an important influence on the structure of the silicaalumina-oxygen framework. This explains two phenomena:
The lack of solid solution between two potential end members of a solid solution series (for instance phillipsite-gismondite),
and the large number of different zeolites in nature, where a great variety in the ratios of available alkali and alkaline
earths ions must be expected.
Any classification of zeolites becomes still more difficult in view of the fact that conversions among different groups (chabazite
→ phillipsite) and different structures (three-dimensional framework → fibre) take place relatively easily.
Contribution No. 59–92, College of Mineral Industries, The Pennsylvania State University, University Park, Pennsylvania. 相似文献
14.
Binyam L. Alemu Per Aagaard Ingrid Anne Munz Elin Skurtveit 《Applied Geochemistry》2011,26(12):1975-1989
Crushed rock from two caprock samples, a carbonate-rich shale and a clay-rich shale, were reacted with a mixture of brine and supercritical CO2 (CO2–brine) in a laboratory batch reactor, at different temperature and pressure conditions. The samples were cored from a proposed underground CO2 storage site near the town of Longyearbyen in Svalbard. The reacting fluid was a mixture of 1 M NaCl solution and CO2 (110 bar) and the water/rock ratio was 20:1. Carbon dioxide was injected into the reactors after the solution had been bubbled with N2, in order to mimic O2-depleted natural storage conditions. A control reaction was also run on the clay-rich shale sample, where the crushed rock was reacted with brine (CO2-free brine) at the same experimental conditions. A total of 8 batch reaction experiments were run at temperatures ranging from 80 to 250 °C and total pressures of 110 bar (∼40 bar for the control experiment). The experiments lasted 1–5 weeks.Fluid analysis showed that the aqueous concentration of major elements (i.e. Ca, Mg, Fe, K, Al) and SiO2 increased in all experiments. Release rates of Fe and SiO2 were more pronounced in solutions reacted with CO2–brine as compared to those reacted with CO2-free brine. For samples reacted with the CO2–brine, lower temperature reactions (80 °C) released much more Fe and SiO2 than higher temperature reactions (150–250 °C). Analysis by SEM and XRD of reacted solids also revealed changes in mineralogical compositions. The carbonate-rich shale was more reactive at 250 °C, as revealed by the dissolution of plagioclase and clay minerals (illite and chlorite), dissolution and re-precipitation of carbonates, and the formation of smectite. Carbon dioxide was also permanently sequestered as calcite in the same sample. The clay-rich shale reacted with CO2–brine did not show major mineralogical alteration. However, a significant amount of analcime was formed in the clay-rich shale reacted with CO2-free brine; while no trace of analcime was observed in either of the samples reacted with CO2–brine. 相似文献
15.
马里亚纳海槽和西菲律宾海盆更新世以来沉积物中的粘土矿物 总被引：4，自引：0，他引：4
根据三个沉积岩芯的研究,马里亚纳海槽和西菲律宾海盆更新世以来的沉积物中粘土矿物明显不同:前者以海槽内基性火山物质蚀变形成的蒙皂石为主,伴随少量铁镁绿泥石和伊利石;后者以来自海盆以西陆上岩石风化形成的伊利石为主,其次为蒙皂石、普通绿泥石和高岭石。这种差别除与物源有关外,主要与两个海盆中的火山活动有关。海槽内粘土矿物也有差异,迷可能与海底热液活动的影响有关。古气候对粘土矿物也有影响,但在海槽则被频繁的火山活动所掩盖。 相似文献
16.
We analyzed the clay mineral assemblages, content and mineralogical characteristics of Hole U1438A sediment recovered from Amami Sankaku Basin during International Ocean Discovery Program (IODP) expedition 351. The results show that the clay minerals are mainly composed of illite (average 57%), smectite (average 26%), chlorite (average 14%) and minor kaolinite(average 3%). The crystallinity of illite in all samples are good (<0.4 Δ° 2θ), and the chemical indexes of illite in all samples are low (<0.4). Both indicate that illite in Hole U1438A formed in cold and dry climate. By comparing clay mineral assemblages of hole U1438A and the potential sediment sources, we suggest that smectite be mainly derived from the volcanic materials around Amami Sankaku Basin. Illite, chlorite and kaolinite are mainly derived from the Asian dust. The ratios of (illite+chlorite)/smectite show a phased increase over the last 350 ka, which is consistent with the cold and drying trend of the Asian continent since late Pleistocene. The high ratios of (illite+chlorite)/smectite and (illite+chlorite)/kaolinite during glacial period indicate that much more Asian dust was input into the Amami Sankaku Basin, which are responded to the aridity of Asian continent and strengthened east Asian Monsoon during glacial period. 相似文献
17.
苏北盆地粘土矿物转化模式与古地温 总被引：16，自引：0，他引：16
以苏北盆地为例,系统研究了火成岩发育区粘土矿物组合特征及其控制因素;建立了粘土矿物转化模式;根据粘土矿物成岩演化特点,进行古地温分析。研究表明,苏北地区粘土矿物的分布主要受埋藏成岩作用、岩浆侵入、母质来源三种因素的影响,发育四种类型的粘土矿物组合和三种粘土矿物转化模式;火山碎屑岩母岩区和基性岩浆侵入区具有特殊的粘土矿物组合和成岩演化模式,前者以富含蒙皂石矿物为特点;后者出现高岭石与伊/蒙有序间层矿物共生组合,并具有不连续的演化序列;苏北盆地短有序I/S矿物出现于镜质组反射率 0.5 %～ 0.5 5 %的深度,伊/蒙间层矿物转变成伊利石在镜质组反射率 0.75 %～ 0.8%,可以用于热成熟度和古地温的估算;而蒙皂石消失的界面则不具有指标意义 相似文献
18.
蒙脱石+伊/蒙混层+伊利石等粘土矿物混合物相X射线定量分析方法—模拟定量法 总被引：3，自引：0，他引：3
本文提出粘土矿物(特别是含伊/蒙不规则混层粘土矿物)混合物相的X射线定量分析方法——模拟定量法。着重解决在蒙脱石-不规则伊/蒙混层粘土矿物-伊利石组合中,伊/蒙混层粘土矿物的定量分析计算。模拟定量法是对以前的各种粘土矿物X射线定量分析方法的补充。用纯净的蒙脱石、伊利石、高岭石、绿泥石及各种伊/蒙混层比的伊/蒙混层粘土矿物,配制了各种不同组合的粘土矿物混合样品,制成定向薄膜片,进行了X射线分析,讨论了各种组合的粘土矿物混合物相X射线衍射图谱的特征,并在此基础上提出了粘土混合物相定量分析的方法。 相似文献
19.
天然沸石是岩石圈上部分布最广的硅酸盐矿物之一,它普遍地见于各种火山岩和火山-沉积岩中。沸石不仅在岩浆期后热液阶段生成,而且在沉积-成岩作用阶段、表生作用(风化)阶段、低级变质阶段都可以生成。由于沸石对周围的物理化学条件和热、动力变质作用反应灵敏,因此,它是了解地质体形成时的地质环境及其变化的良好的指示矿物。本文概述了我国东部中生代火山岩中沸石岩的分布、时代、产出的地层岩性剖面、原岩类型、矿物组合及其生成顺序,并探讨了它的形成条件和成因类型,其中主要涉及具有工业意义的斜发沸石岩和丝光沸石岩。 相似文献
20.
对伊豆-小笠原海脊(ODP 782A孔)上新世以来沉积物中黏土矿物的组成、含量及矿物学特征进行了分析,结果表明:黏土矿物以伊利石(42%)和蒙皂石(42%)为主,绿泥石的平均含量为14%,高岭石的含量最低,平均仅为2%。伊利石的结晶度较好,平均为0.25°Δ2θ;化学指数较低,平均为0.31;表明伊利石主要形成于干冷的气候环境。通过将ODP 782A孔黏土矿物组合特征和含量与周边可能源区对比,并结合伊利石和蒙皂石的矿物学参数特征,我们认为蒙皂石主要来源于伊豆-小笠原海脊周边岛弧火山物质;伊利石、绿泥石和高岭石主要来自亚洲大陆风尘。上新世以来(伊利石+绿泥石)/蒙皂石比值总体上呈增加的趋势,并且在5.3~3.6、3.6~1.6、1.6~0 Ma的三个阶段表现出不同的变化特征,该比值与全球深海δ18O值所记录的全球变冷、北太平洋ODP 885/886孔风尘通量和灵台黄土沉积速率,以及日本海U1430站伊利石/蒙皂石比值所指示的亚洲内陆干旱变化的总体变化趋势和阶段性变化的时间点大致同步,表明该比值敏感地响应了全球变冷和亚洲内陆的干旱。上新世以来(伊利石+绿泥石)/高岭石比值表现为高/低交替变化,分别与中国灵台黄土磁化率高/低变化相对应,由于黄土磁化率记录了亚洲内陆干/湿变化,因此该黏土矿物比值敏感地响应了亚洲内陆的古气候变化,因而可以作为可靠的亚洲大陆干/湿变化示踪指标。 相似文献