共查询到20条相似文献，搜索用时 46 毫秒
1.
The composition of sand-silt and pelite fractions of deep-sea sediments deposited under different hydrodynamic conditions
was studied. Assemblages of clastic, clayey, biogenic, and authigenic minerals formed under the influence of surface and bottom
currents were traced. It is shown that biogenic opal, fine-dispersed celestobarite, and authigenic protosyngenetic ferromanganese
micronodules, which are composed of only manganese phases, represent indicators of cyclonic gyres characterized by enhanced
bioproductivity. Collophane (bone detritus), phillipsite, palagonite, and large celestobarite crystals prevail in mineral
assemblages below the anticyclonic gyres, whereas ore micronodules are depleted in manganese. Surface and bottom currents
control the distribution of clastic (terrigenous edaphogenic, terrestrial-volcanogenic) and clay minerals, as well as biogenic
opal in the form of Ethmodiscus frustules in sediments. Edaphogenic mineral assemblages represent the reliable indicators of bottom currents. 相似文献
2.
Tuff deposits of the Koko Crater group consist largely of alkali basalt glass, either fresh or palagonitized. Most of the deposits are progressively palagonitized at depth, and topographic relations of palagonite on Koko Crater indicate that the palagonite was formed after the cone had been deeply eroded.The principal authigenic minerals in the palagonite tuffs were deposited in following sequence: phillipsite, chabazite, analcime, montmorillonite together with opal, and calcite. The amount of authigenic minerals in a given sample is generally proportional to the amount of palagonite, indicating that the authigenic minerals are produced in palagonitization of glass.Chemical analyses of sideromelane and associated palagonite by the electron microprobe show that about a quarter of the SiO2, half of the Al2O3 and MgO, and three quarters or more of the CaO, Na2O, and K2O are lost in converting sideromelane to an equal volume of palagonite. A substantial proportion of these components lost from the sideromelane are precipitated nearby in zeolites, montmorillonite, opal, and calcite.Reaction of sideromelane with percolating ground water at low temperatures accounts for the vertical zoning from relatively fresh tuffs down into palagonite tuffs. The pH and ionic strength of percolating water probably increased with depth by solution and hydrolysis of glass, and where the pH and ionic strength became sufficiently high, the glass reacted to form palagonite and zeolites. Palagonite was formed by a microsolution-precipitation mechanism rather than by hydration or devitrification. 相似文献
3.
Sridhar D. Iyer M. Sudhakar P. Das 《《地质学报》英文版》2007,81(5):756-770
We examined more than fifty indurated sediments recovered from the Central Indian Ocean Basin （CIOB） during the course of collection for manganese nodules and crusts. The samples occur as slabs either over which ferromanganese oxides are present or over a substrate of altered oceanic basalt in conjunction with palagonite or within the nucleus of manganese nodules. Mineralogically and compositionally, the samples show a mixture of phillipsite, palagonite and montmorillonite. We suggest that the volcanogenic precursors occurring in the CIOB were subjected to varying degrees of alteration under the influence of low temperature conditions, resulting in the formation of zeolitic claystones. The CIOB samples have similarities to those reported from various sites in the world oceans. 相似文献
4.
通过对江汉平原主要河流沉积物的重矿物组合、特征矿物以及能够反映沉积物稳定状况、物源及成熟度的重矿物特征指数(ATi,GZi和ZTR)进行对比分析,发现在江汉平原范围内,长江和汉江及其长江主要支流的沉积物中重矿物特征具有显著的差异。长江的重矿物组合模型为： 锆石+绿帘石+辉石+绿泥石+金属矿物,特征矿物是锆石和辉石; 汉江的重矿物组合模型为： 绿帘石+角闪石+石榴石+绿泥石+金属矿物,特征矿物是角闪石、石榴石; 另外,清江、漳河、沮水和玛瑙河的重矿物组合及特征矿物也都完全不同。而且各水系的沉积物的重矿物特征与其源区的岩性分布显示出极好的相关性。研究表明在江汉平原利用重矿物特征及组合模型来进行物源示踪的方法开展水系演化研究是可行的。 相似文献
5.
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
6.
7.
长江水系沉积物碎屑矿物组成及其示踪意义 总被引：24，自引：2，他引：22
长江碎屑矿物组成研究表明,轻矿物以石英、长石和岩屑为主,不同支流轻矿物组成特征不同,成熟度指数平均是2.0,一般干流高于支流,成熟度随沉积物搬运距离增加而增大。QFL及QtFL三角图解显示长江沉积物主要来自再旋回造山带物源区,流域风化剥蚀速度较快,不同支流物质汇入干流,使得干流轻矿物组成复杂多变而难以和支流区别。重矿物含量从长江上游至下游呈递减趋势,其主要组合是磁铁矿-普通角闪石-普通辉石-石榴子石-绿帘石-褐铁矿-钛铁矿。红柱石和磷灰石是金沙江沉积物的特征矿物组合;蓝晶石是岷江流域的特征矿物;涪江的特征矿物是榍石;汉江的特征矿物组合是磷灰石、紫苏辉石和硅镁石;锆石是湘江的特征矿物。不同流域的特征矿物指示其源岩性质。上游的雅砻江、大渡河以及岷江等支流沉积物对中、下游干流沉积物的贡献较弱。涪陵以上长江流域风化作用强烈,母岩主要是沉积岩类(碎屑岩、泥岩);其下流域沉积物中近源弱风化物质明显增加,其源岩类型体现为岩浆岩和变质岩类;而金沙江攀枝花地区及湘江、沅江沉积物则更多来自流域内广泛分布的大片变质岩类。 相似文献
8.
Agglutinated deep-sea benthonic foraminifera with tests composed of phillipsite are documented and illustrated from a red clay sequence in a Giant Piston Core from the central North Pacific. Associated with the benthonic foraminifera are phillipsite crystal rosettes and aggregates of phiilipsite crystals. The benthonic foraminifera and phillipsite crystals constitute most of the > 38 μm fraction, but have little effect upon the mean size of the red clay sediments. 相似文献
9.
黔西南微细浸染型金矿床中标型矿物特征初探 总被引：4，自引：0，他引：4
黔西南微细浸染型金矿床中标型矿物有:黄铁矿、毒砂、石英、水云母和褐铁矿,主要的是黄铁矿。阐述了这些标型矿物的特征及其与金的成矿关系。 相似文献
10.
11.
12.
13.
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
14.
莺歌海盆地东北部邻区7条主要入海河流重砂矿物特征及其地质意义 总被引：1，自引：0，他引：1
海南岛西部（琼西）是莺歌海盆地东北部的主要物质来源之一。本文对琼西7条主要河流入海口的现代河砂进行了重矿物含量、重矿物组合以及相关特征指数等分析,发现其重矿物含量、磨圆度、组合以及相关重矿物指数从北到南明显不同,反映出碎屑物质搬运距离和源区岩性也明显不同。北部珠碧江重矿物以钛铁矿、电气石、锆石、绿帘石和透闪石为主,磨圆度较差,反映物源主要为近距离的酸性至基性-超基性岩浆岩和变质岩;昌化江重矿物以钛铁矿、磁铁矿、锆石和榍石为主,磨圆比较好,物源可能主要为远距离的酸性和基性岩浆岩;中部北黎河和通天河重矿物以钛铁矿、电气石、锆石、石榴石和透闪石为主,基本没有磨圆,物源主要来自近源区,为未经远距离搬运的变质岩、酸性岩浆岩和基性火山岩;感恩河重矿物以磨圆度差的锆石、钛铁矿、榍石、电气石和褐铁矿等稳定-极稳定重矿物为主,反映源区主要为近距离搬运的岩浆岩;南部望楼河和宁远河重矿物以钛铁矿、磁铁矿、褐铁矿和绿帘石等稳定-不稳定矿物为主,反映的母岩主要为酸性岩浆岩、变质岩和中-基性岩浆岩。这些主要河流入海口的重矿物特征存在明显差异,这与其发源地、流经区域以及流经区域所发育的岩石类型相一致。通过研究琼西地区从北到南不同流域的重矿物组合体系,有助于开展莺歌海盆地源汇对比分析,建立不同区域油气储层碎屑物质来源的识别标志,对该盆地天然气储层物源识别具有重要的地质意义。 相似文献
15.
16.
《International Geology Review》2012,54(10):907-916
The widely applied method of stratigraphic division of sediments and their correlation on the base of terrigenous components developed by 11ling, Baturin and others, was based on the fact that the composition of the sedimentary terrigenous components depends upon the petrographic composition of the distributive province rocks. The author, using terrigenous components for stratigraphic purposes, has based his method of the influence of the ancient crusts of weathering upon their composition. Under the ancient kaolin-type weathering conditions the mineralogy of forming sediments was very uniform: among rock-building minerals prevailed quartz, kaolin, partly hydromicas. Among accessories the following stable minerals prevailed: ilmenite, leucoxene, chromite, zircon, rutile, disthen, staurolite, tourmaline, cassiterite, and also less widely spread minerals such as sillimanite, anatase, brucite, corundum, xenotime, columbite, monazite, topaz, spinel, andalusite, diamond, gold, platinum, osmiridium. Unstable under the ancient kaolin weathering conditions were: garnets, pyroxenes, amphiboles, epidote, magnetite, apatite, sphene, serpentine, olivine, titano-magnetite. Their contents in the deposits, formed at the expense of the kaolin crust of weathering, were as a rule insignificant. From the above it is clear that the ancient weathering could have affected the mineralogical composition of accessory minerals of deposits, even much stronger than the petrographical composition of the distributive province. In the course of geological times the total balance of stable accessory minerals, able to undergo repeated weathering and erosion, has the tendency to grow in spite of their dilution in sediments during certain epochs. The author tried to give a stratigraphic division of the Mesozoic and Cenozoic deposits in the South Urals from terrigenous components. This method can find a wide application. In the future it will be advisable to combine the above mentioned method with the method of Illing and Baturin and others, taking into account the petrographic influence of the rocks of the distributive province. — Auth. English Summ. 相似文献
17.
Petrogenesis of sediments in the absence of chemical weathering: effects of abrasion and sorting on bulk composition and mineralogy 总被引：15，自引：0，他引：15
Comminution in the glaciers that debouch into Guys Bight Basin, followed by selective sorting in the fluvial system, has had little effect on the bulk composition, or on the mineralogy, of the basin sands and muds. Most striking are the feldspar contents, and the feldspar-quartz ratios in sands and muds, both of which remain similar to those of average bedrock. The feldspar contents of sands and muds range from 48 to 52% feldspar whereas average bedrock contains 51·7% feldspar. Feldspar-quartz ratios average 1·58:1 in bedrock and 1·54:1, 1·66:1 and 1·69:1 in the medium to coarse sands, fine sands and muds, respectively, indicating minimal feldspar enrichment in the fine-grained sediments. In the absence of appreciable chemical weathering, extreme abrasion followed by hydraulic sorting has not produced mature sediments such as quartz arenites and clay-mineral-rich muds. There is, however, some chemical differentiation. Preferential accumulation of mafic minerals in fine sands and muds is reflected in bulk compositions by higher abundances of MgO, FeO and TiO2, and in the mineralogy by enrichment of biotite in the fine grades. Bulk compositional studies focused solely on muds and mudstones will result in an overestimate of the mafic contribution from source rocks. This work shows that bulk compositional studies of sediments and sedimentary rocks should include all available granulometric grades. 相似文献
18.
大黄花铜多金属矿位于赤峰-朝阳金多金属成矿带南部,矿化发生在燕山期正长花岗岩与石炭系酒局子组大理岩接触部位,局部构成铜（铁）矿体.夕卡岩矿物主要为石榴石、透辉石、透闪石、绿帘石、绿泥石、角闪石及阳起石,金属矿物有黄铜矿、辉铜矿、黝铜矿、斑铜矿、铜蓝及氧化次生矿物蓝铜矿、孔雀石、褐铁矿.围岩蚀变强烈,呈现清晰的蚀变分带现象,自接触带向外可分为较强的透闪石-阳起石化带,较强的透闪石-透辉石化带,弱蚀变的大理岩化带.金属元素组合特征明显,为Cu、Pb、Zn、Au、Ag组合.该铜多金属矿的形成与正长花岗岩的侵入作用有关,成矿时代为中侏罗世晚期,与朝阳-赤峰地区金多金属矿成岩成矿时代一致. 相似文献
19.
大黄花铜多金属矿位于赤峰-朝阳金多金属成矿带南部，矿化发生在燕山期正长花岗岩与石炭系酒局子组大理岩接触部位，局部构成铜（铁）矿体.夕卡岩矿物主要为石榴石、透辉石、透闪石、绿帘石、绿泥石、角闪石及阳起石，金属矿物有黄铜矿、辉铜矿、黝铜矿、斑铜矿、铜蓝及氧化次生矿物蓝铜矿、孔雀石、褐铁矿.围岩蚀变强烈，呈现清晰的蚀变分带现象，自接触带向外可分为较强的透闪石-阳起石化带，较强的透闪石-透辉石化带，弱蚀变的大理岩化带.金属元素组合特征明显，为Cu、Pb、Zn、Au、Ag组合.该铜多金属矿的形成与正长花岗岩的侵入作用有关，成矿时代为中侏罗世晚期，与朝阳-赤峰地区金多金属矿成岩成矿时代一致. 相似文献
20.
合成金刚石生产中叶蜡石传压密封材料矿物学研究 总被引：7，自引：0，他引：7
叶蜡石是高温高压合成金刚石的关键辅助材料。叶蜡石传压密封材料的性能主要取决于叶蜡石矿石的矿物组成。叶蜡石矿石中的杂质矿物主要是一水硬铝石、明矾石、长石、高岭石、绢云母、绿泥石、石英、赤铁矿、钛铁矿、褐铁矿、金红石等。具有层状结构的矿物－水硬铝石、高岭石、绢云母、绿泥石等总量不超过10％，不会影响制品的传压性能。明矾石在高温高压下不稳定，是有害组分。长石、石英等非层状结构的矿物含量高时，会使叶蜡石传压密封材料静压流变特性变差，对传压性能是有害组分，应控制在小于5％，非常纯净的叶蜡石矿石制成的粉压块传压性能良好，但内摩擦系数小，密封性能差，常发生高压挤出和顶锤破坏现象，少量的赤铁矿、钛铁矿、褐铁矿、金红石矿物存在可以提高密封性能。 相似文献