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1.
Although Mn is one of the major impurities in the economic iron ores from the Bahariya Oasis, information on its modes of occurrence and origin is lacking in previous studies. High-Mn iron ores from El Gedida and Ghorabi–Nasser iron mines were subjected to detailed mineralogical, geochemical, and petrographic investigations using X-ray diffraction (XRD), infrared absorption spectrometry (IR), Raman spectroscopy, X-ray fluorescence (XRF), scanning electron microscopy (SEM), and electron probe microanalyzer (EPMA) to clarify the modes of occurrence of Mn in these deposits and its origin. The results showed that the MnO2 contents range between 0.03 and 13.9 wt.%. Three mineralogical types have been identified for the Mn in the high-Mn iron ores, including: (1) inclusions within the hematite and goethite and/or Mn accumulated on their active surfaces, (2) coarse-grained and crystalline pyrolusite, and (3) fine-grained cement-like Mn oxide and hydroxide minerals (bixbyite, cryptomelane, aurorite, romanechite, manjiroite, and pyrochroite) between the Fe-bearing minerals. The Mn carbonate mineral (rhodochrosite) was detected only in the Ghorabi–Nasser high-Mn iron ores. Since IR patterns of low-Mn and high-Mn samples are almost the same, a combination of XRD analysis using non-filtered Fe-Kα radiations and Raman spectroscopy could be the best way to identify and distinguish between different Mn minerals.Assuming that both Fe and Mn were derived from the same source, the occurrence of high-Mn iron ores at the base of the stratigraphic section of the deposits overlain by the low-Mn iron ores indicated a supergene origin of the studied ores by descending solutions. The predominance of Mn oxide and hydroxide minerals in botryoidal shapes supports this interpretation. The small grain size of Mn-bearing minerals as well as the features of microbial fossils such as spherical, elliptical, and filamentous shapes of the Fe-bearing minerals suggested a microbial origin of studied iron ores.Variations in the distribution and mineralogy types of Mn in the iron ores of the Bahariya Oasis demanded detailed mineralogical and petrographic characterizations of the deposits before the beneficiation of high-Mn iron ores from the Bahariya Oasis as feedstock for the ironmaking industries in Egypt by magnetizing reduction. High Mn contents, especially in the Ghorabi–Nasser iron ore and occurrence of Mn as inclusions and/or accumulated on the surface of the Fe-bearing minerals would suggest a possible utilization of the high-Mn iron ores to produce ferromanganese alloys. 相似文献
2.
《Journal of African Earth Sciences》2010,57(4-5):179-189
The type section of the Lower Cenomanian Bahariya Formation at Gebel El-Dist (Bahariya Oasis, Western Desert), Egypt, comprises claystones, mudstones, siltstones and sandstones deposited in fluvial-deltaic coastal plain, lagoonal, estuarine and shallow marine environments. The formation is characterized by an abundance of ferruginous sandstones that locally weather to form prominent iron crusts. These centimeter to decimeter-scale ferruginous horizons display a continuum of features ranging from unaltered sandstone with a pervasive ferruginous matrix to distinct ironstone beds with massive, nodular, vesicular and pisolitic textures. Ferruginous sandstone typically occurs at the tops of sandstone beds, or bracketing the base and top of beds, in the fining-upward cycles of deltaic plain deposits in the lower part of the formation and on a low-energy fluvial floodplain in the middle of the formation. Indurated ironstone beds occur mainly as the caps of coarsening-upward cycles of prograding shoreface sediments through much of the formation. We interpret the ironstone crusts as ferricretes, formed by iron accumulation that resulted from the oxidation and precipitation of soluble iron or colloids transported in the sediment load or by groundwater. This accumulation possibly took place at the water table or possibly below the water table at the fresh water/saline water interface. However, base-level fall and subsequent subaerial exposure of the sediments resulted in reworking and pedogenic modification of some of the iron-impregnated horizons. 相似文献
3.
The Campanian-Maastrichtian Agbaja Ironstone Formation of the Nupe basin, Nigeria, forms a major part of the about 2 billion
tons of iron ore reserves of the Middle Niger Embayment. The ironstone deposits were previously reported to be similar to
the Minette-type ironstones because of their depositional patterns, composition and inferred origin. Four rock-types are recognized
within the Agbaja Ironstone Formation: ooidal pack-ironstone, pisoidal pack-ironstone, mud-ironstone and bog iron ore. In
the ironstones, kaolinite of both the groundmass and the ooids/pisoids is of lateritic origin, whereas the associated quartz,
mica and heavy minerals are of detrital origin. Ooids and pisoids were formed by mechanical accretion of platy kaolinite crystals
by rolling on the sea floor in a near-shore environment, and were subsequently transported and deposited together with a fine-grained
kaolinitic groundmass. Pyrite (mainly framboidal) and siderite (both exclusively occurring as pseudomorphs of goethite and/or
hematite) are diagenetic whereas goethite is post-diagenetic in origin, resulting from the ferruginization of the kaolinitic
precursor. Crandallite-gorxeicite-goyazite, bolivarite and boehmite are also post-diagenetic in origin. Hematite was formed
from the dehydration of goethite, whereas gibbsite (restricted to the upper part of the deposit) is of recent and in situ lateritic origin. The presence of newly formed authigenic pyrite and siderite (now replaced by hematite and goethite) are
indicators of a reducing environment during diagenesis. The absence of diagenetic chamositic clay minerals, evidently caused
by a low Mg concentration, suggests that fully marine conditions were not established during sedimentation. This is supported
by the lack of fossils, brecciated shell materials and bioturbation features in the deposit. Reworking and redeposition of
the primary constituents are inferred from broken pisoids, nuclei of pisoidal/ooidal fragments in pisoids and high iron concentrations
present in the pisoids and ooids compared to that of the groundmass. These observations indicate that the Agbaja ironstone
deposits of the Lokoja study area exhibit some environmental and mineralogical characteristics that are markedly different
from other known deposits of Minette-type, where primary chamositic clay minerals generally form the protore for the ironstones.
The recognition of kaolinite as the precursor constituent and the occurrence of similar deposits of the same age (Late Cretaceous)
in Nigeria, Sudan and Egypt have implications for the paleoenvironmental interpretations of Phanerozoic ironstone deposits.
Received: 16 February 1998 / Accepted: 8 July 1998 相似文献
4.
Lower and middle Eocene ironstone sequences of the Naqb and Qazzun formations from the north‐east Bahariya Depression, Western Desert, Egypt, represent a proxy for early Palaeogene climate and sea‐level changes. These sequences represent the only Palaeogene economic ooidal ironstone record of the Southern Tethys. These ironstone sequences rest unconformably on three structurally controlled Cenomanian palaeohighs (for example, the Gedida, Harra and Ghorabi mines) and formed on the inner ramp of a carbonate platform. These palaeohighs were exposed and subjected to subaerial lateritic weathering from the Cenomanian to early Eocene. The lower and middle Eocene ironstone sequences consist of quiet water ironstone facies overlain by higher energy ironstone facies. The distribution of low‐energy ironstone facies is controlled by depositional relief. These deposits consist of lagoonal, burrow‐mottled mud‐ironstone and laterally equivalent tidal flat, stromatolitic ironstones. The agitated water ironstone facies consist of shallow subtidal–intertidal nummulitic–ooidal–oncoidal and back‐barrier storm‐generated fossiliferous ironstones. The formation of these marginal marine sequences was associated with major marine transgressive–regressive megacycles that separated by subaerial exposure and lateritic weathering. The formation of lateritic palaeosols with their characteristic dissolution and reprecipitation features, such as colloform texture and alveolar voids, implies periods of humid and warm climate followed major marine regressions. The formation of the lower to middle Eocene ironstone succession and the associated lateritic palaeosols can be linked to the early Palaeogene global warming and eustatic sea‐level changes. The reworking of the middle Eocene palaeosol and the deposition of the upper Eocene phosphate‐rich glauconitic sandstones of the overlying Hamra Formation may record the initial stages of the palaeoclimatic transition from greenhouse to icehouse conditions. 相似文献
5.
以电子探针(EPMA)为主要研究手段,结合常规化学分析、化学物相分析、透反射显微镜研究,对黔西北某地低品位铁矿中铁—钛的赋存状态进行了详细研究。研究结果表明,矿石中铁主要以褐铁矿形式存在,少量以赤铁矿产出。载铁矿物与粘土矿物常常混杂出现,分布不均,团块大小差异也大,矿物间的嵌布关系复杂;钛在矿石中一是以微细粒的独立矿物金红石、锐钛矿、钛铁矿与脉石矿物相互混杂分布,另一种则是蚀变残留于褐铁矿中类质同象的钛。根据铁、钛赋存特征研究结果,对该矿石提出了"分散—絮凝—磁选"分离预富集铁—钛矿物、"直接还原法"实现铁钛分离的工艺建议。 相似文献
6.
The economic iron ore deposits of Egypt are located at Bahariya Oasis in the Lower Middle Eocene limestone. The main iron minerals are goethite, hematite, siderite, pyrite, and jarosite. Manganese minerals are pyrolusite and manganite. Gangue minerals are barite, glauconite, gibbsite, alunite, quartz, halite, kaolinite, illite, smectite, palygorskite, and halloysite. Geochemical comparison between the ore and the Nubia sandstone showed that the ore is depleted in the residual elements (Al, Ti, V, and Ni) and enriched in the mobile elements (Fe, Mn, Zn, Ba, and U) which indicates that the Bahariya iron ore is not a lateritic deposit despite the deep weathering in this area. On the other hand, the Nubia sandstone showed depletion in the mobile elements, which demonstrates the leaching process in the Nubia Aquifer. The presence of such indicator minerals as jarosite, alunite, glauconite, gibbsite, palygorskite, and halloysite indicate that the ore was deposited under strong acidic conditions in fresh water.Isotopic analyses of the uranium in the amorphous and crystalline phases of the ore, in the country rocks, and dissolved in the Nubia Aquifer water, all support the conclusion that U and Fe were precipitated together from warm ascending groundwater. U and Fe display strong co-variation in the ore, and the 234U/238U activity ratio of the newly precipitated U in the country rock and the leached component of U in the groundwater are identical. There is only slightly more uranium in the amorphous phase than in the crystalline and only a slightly lower 234U/238U activity ratio, suggesting that the iron in the two phases have a similar origin. Comparison of the excess 234U in the water and in the total ore leads to the conclusion that the precipitation of the U, and by inference the iron, occurred within the last million years. However, that both precipitation and leaching of U have occurred over the last 300,000 years is evidenced by the extreme 230Th/234U disequilibria observed in some of the samples. Some of the amorphous depositional events have been very recent, perhaps within the last 10,000 years. 相似文献
7.
辽宁本溪大台沟铁矿地质特征及找矿标志 总被引：1，自引：0，他引：1
辽宁本溪大台沟铁矿为鞍山-本溪铁矿成矿带内发现的首个位于标高-1000 m以下的特大型“鞍山式”铁矿床,含矿岩系为近直立展布的鞍山群樱桃园岩组,包含其内的铁矿体为隐伏的厚板状陡倾斜矿体,矿体埋深1100~1200 m,控制矿体延长2000 m.矿体自上向下可划分3种自然矿石类型,分别为赤铁矿石、赤铁磁铁复合矿石及磁铁矿石.大台沟铁矿床属典型“鞍山式”铁矿床,矿物成分较简单,含铁矿物以磁铁矿和赤铁矿（镜铁矿）为主;矿石结构类型有镶嵌粒状变晶结构、鳞片粒状变晶结构、柱状粒状变晶结构等;矿石构造类型以条带状为主.铁矿石TFe品位平均为29.34%;mFe品位平均为14.63%;矿石中其他元素含量除SiO2较高外,均甚微,SiO2平均含量46.08%.笔者在阐述大台沟铁矿地质特征基础上,总结出大台沟铁矿找矿标志,对于区域内潜在的“大台沟式”（埋藏较深、存在高大磁异常）铁矿床的找寻具有一定借鉴意义. 相似文献
8.
The distribution of old workings, or ‘minepits’, for clay ironstone in an area between Horsham and Crawley is shown on geological sketch-maps. The geological structure of the area is described in outline. The old workings, except for those in two anomalous patches, are restricted to two argillaceous units in the Upper Tunbridge Wells Sand and to an ironstone horizon some 2 m. below the Horsham Stone in the Weald Clay. Slags from two bloomery sites are described. The amount of ore dug from the minepits is estimated to correspond roughly to the requirements of local blast furnaces, of sixteenth- and seventeenth-century date. Depletion of iron ore reserves is suggested as a factor deciding against resumption of the iron industry in the area after the Civil War. 相似文献
9.
The mineralogy of the managanese ores of the giant Paleoproterozoic Kalahari manganese deposit of the Transvaal Supergroup has been subject of many studies and up to now 135 different ore and gangue minerals have been described, of which eight represent new mineral species. Through correlation of different mineral assemblages with specific geological events and by determining relative ages of minerals in outcrop, hand specimen and under the microscope an attempt is made in this publication to construct a paragenetic sequence for this complex mineral assemblage. Sedimentation and early diagenesis of the Hotazel Formation, composed of interbedded iron formation and braunite lutite, was followed by low-grade metamorphism and associated stratabound metasomatism. Braunite lutite of sedimentary origin, comprising 97% of the total ore reserve, is composed of braunite, hematite and kutnahorite, and abundant early diagenetic kutnahorite and manganoan calcite forming laminae and ovoids. Fluid flow during late diagenesis or lower greenschist facies metamorphism led to stratabound metasomatic oxidation of Mn-bearing carbonates to hausmannite and Mn-poor calcite. Three structurally controlled hydrothermal alteration events succeed metamorphism. These events are referred to as Wessels, Mamatwan and Smartt events. The Wessels alteration event is the oldest of the three events and it is of great economic importance because virtually all of the high-grade ore (> 42% Mn), 3% of the total ore reserve, formed during this event through alteration of carbonate-rich low-grade Mamatwan-type ore (braunite lutite) to high-grade, carbonate-poor Wessels-type manganese ore. This Wessels hydrothermal alteration event took place in the northwestern part of the Kalahari deposit, associated with a system of major north-south- and minor east-west-striking normal faults. The Mamatwan alteration event is observed throughout the Kalahari manganese deposit but alteration is very localized. Reduction halos and discolouration of braunite lutite around fracture or joint-hosted sulphide-carbonate mineralization are typical of the Mamatwan alteration event. In contrast, the Smartt alteration event is characterized by oxidation of braunite lutite and the formation of todorokite and manganomelane. Syn- and Post-Kalahari supergene alteration has taken place below the suboutcrop of the Hotazel Formation against the calcretized sediments of the Cenozoic Kalahari Formation. Cryptomelane and pyrolusite are the predominant products of surficial weathering. 相似文献
10.
Fetullah Arik 《Journal of the Geological Society of India》2012,80(6):855-868
Gözeçukuru As-Sb-Pb-Zn mine is located 1.2 km NW of Sahin village and 22 km west of Kütahya in NW Turkey. The aim of this study is to explain the genetic characteristics of the As-Sb deposits by using multivariate statistical analysis methods. Low-grade metamorphic rocks of the upper Paleozoic Sahin Formation occur as the basement of the study area. Cenozoic volcano-sedimentary units (Tavsanli volcanites and Emet Formation) overlie the Sahin Formation unconformably. The mineralization occurs mainly as veins and partly as disseminations and fillings of interstices in the rhyodacitic and rhyolitic tuffs of Tavsanli Volcanics. Common primary ore minerals are stibnite, realgar, galena, sphalerite, pyrite and arsenopyrite, and secondary minerals are orpiment, senarmontite and valentinite. Barite is the dominant gangue mineral, with a small amount of quartz, calcite and dolomite. Average As, Sb, Pb, Zn and Ba concentrations in the samples from the study area are 6.04%, 4938 ppm, 4589 ppm, 1.17% and 10.36 % respectively. Three significant groups appear in the cluster analysis of ore samples. First group consists of Pb-Ag and Zn-Cd. The second group consists of Sb-Tl-Hg and As. The last group is the Ba-Sr. There are three significant factors in the factor analysis. First factor reflects the formation of primary sulphide minerals, the second factor represents the formation of low temperature sulphide and sulphosalt minerals and the last factor depicts interstices-filling mineralization. Average homogenization temperature of the fluid inclusion in barites is 221 °C. Geological, petrographical and geochemical data suggest that the Gözeçukuru As-Sb deposit was formed under epithermal conditions. 相似文献
11.
F. C. Loughnan 《Australian Journal of Earth Sciences》2013,60(1):177-192
A detailed petrological study has been made of a complete section of the Narrabeen Group exposed in a bore near Helensburgh. The Clifton Sub‐Group is characterised by two major cycles in which thick units of predominantly arenaceous sediments are interspersed with red‐brown claystones. Rock fragments are abundant in the sandstones, particularly near the base of the sub‐group, while siderite is common as a minor constituent. The red‐brown claystones show a marked contrast in composition with the shaly members of the thicker units in that quartz and siderite are absent or sparse and hematite is prevalent. However, the clay mineral contents of the two claystone formations differ. The upper or Bald Hill Claystone contains only kaolinite, whereas inter‐layered clay minerals and illite are present in addition to kaolinite in the lower or Stanwell Park Claystone. Hematite is absent from the upper few feet of the Bald Hill Claystone and kaolinite, partly in the form of vermicular crystals, may comprise the whole sample but elsewhere boehmite or siderite is prevalent. The texture varies from pisolitic to brecciated. The Gosford Formation overlying the Clifton Sub‐Group is composed predominantly of shales which resemble in texture and composition those of the later Wianamatta Group. A brief discussion of the origin of the Narrabeen Group is given. 相似文献
12.
中国泥盆纪鲕铁石沉积环境、成因 总被引：5，自引：0，他引：5
中国泥盆纪鲕铁石分布在华南的云南、四川、贵州、广西、湖南、江西、湖北等7个省(区)。鲕铁石结构有鲕粒、假鲕粒、凝胶团粒。鲕粒一般有环带、有核心,也有仅有环带、无核心的鲕环2-3层,少数数十层。鲕粒环带、团粒一般为自形晶微粒赤铁矿、绿泥石、菱铁矿,含少量粘土矿物及其他自形品矿物。核心为石英碎屑,或铁矿物碎屑。鲕粒间基质自形晶矿物、粘土矿物及其碎屑矿物。以接近封闭的浅水泻湖环境沉积最好(占鲕铁石总储量60%),以河口三角洲砂坝沉积最差(占4.2%)。鲕铁石是海水中胶体沉积的,当海水有一定能量时,铁质围绕碎屑物或铁矿物碎屑转动沉积鲕粒环带,铁质也可围绕先凝聚的铁矿物转动沉积无核心的环带。当海水能量低时形成凝胶团粒。 相似文献
13.
《矿物学报》2013,(Z1)
Automated core scanning technologies for mineralogical characterisation of diamond core, drill chips pulps is now an established technique, particularly in the Australian iron ore industry, for mineral analysis in exploration and mining. Application of reflectance spectroscopy over the 400–2500 nm, visible to near-infrared wavelength range, has been used to characterise the iron ore oxide mineralogy of bedded iron deposit (BID) derived iron ores in India (Thangavelu et al., 2011) and Brazil (da Costa et al., 2009), and used to define the ore and gangue (e.g., clay) mineralogy in ironstone or channel iron deposits (CID) in the Pilbara region of Western Australia (e.g., Haest et al., 2012). 相似文献
14.
神农架铁矿位于华中第一高峰——鄂西神农架原始林区。目前发现具有工业价值的矿区主要有两个:一个在铁厂河,另一个在大神农架主峰附近(图1)。铁矿露头一般在标高2000—2500米以上。虽然该铁矿沉积形成于元古代,但由于它至今几乎未受变质,使它具有独特的矿石类型,以区别于一般前寒武纪沉积变质铁矿,因此人们专称它为神农架式。现将该铁矿特征简要报道如下。 相似文献
15.
成岩作用及成岩阶段的确定是储集层评价的重要依据。作者应用铸体薄片、阴极发光、扫描电镜的观察,x射线衍射分析及包体测温等方法,对华北一些地区石炭一二叠系砂岩的成岩作用及成岩阶段作了系统的研究。从太原组到上石盒子组,由于沉积环境、岩石类型的差异,它们经历了不同的成岩作用过程。太原组石英砂岩以石英增生与胶结作用为主;山西组长石砂岩及长石石英砂岩以长石及石英增生、碳酸盐胶结交代作用为主;上、下石盒子组粘土含量较高的岩屑砂岩以压实作用、粘土矿物的转化作用为主。 成岩阶段的确定主要根据自生石英中包裹体测温、镜煤反射率测定及粘土矿物的演变等。研究结果得出石炭一二叠系经历的古地温为100—150℃,有机质处于成熟期,粘土矿物转化为以伊利石为主,混层矿物中伊利石达80％,可见研究区内石炭一二叠系的成岩阶段处于中成岩期的晚期。其原始孔隙基本消失,代之以一定次生孔隙。 相似文献
16.
Oxidation of the relatively iron sulfide-poor Dugald River zinc-lead lode in northwest Queensland and reaction of the acid solutions with carbonate has resulted in an undifferentiated gossan profile. The gossan is composed predominantly of quartz, goethite, hematite, barite, adularia, plumbian jarosite, plumbogummite and minor mica, chlorite, kaolinite and montmorillonite. Barite and adularia are formed by the breakdown of the barium feldspar hyalophane (K, Na, Ba)[(Al, Si)4O8] which occurs in the lode.Lead in the gossan is contained within the secondary minerals plumbogummite and plumbian jarosite, and in traces of anglesite and cerussite, whereas Zn occurs in the barite, secondary lead minerals and coronadite structures, and is adsorbed by iron oxides, phyllosilicates and carbonaceous matter. Only traces of zinc minerals smithsonite, goslarite and hemimorphite were detected.Use of Gresens' general metasomatic equation has enabled quantitative determination of compositional changes resulting from the oxidation of the ore. Silicon, Al, Ti and Ba are essentially immobile under the mildly acidic oxidizing conditions. In decreasing order of mobility Cd, Ca, S, Na, K, Mn, Mg, Zn, Ni and Cu, together with CO2 and Tl, have been leached from the gossan profile, while Ag, Sb, Se, As, Fe and Pb appear to have been added to the gossan, notably in a zone of solution-deposited secondary minerals where they have been concentrated, possibly as a result of leaching from the surface gossan. 相似文献
17.
18.
Faiz Ahmad A. H. M. Ahmad M. A. Quasim 《Journal of the Geological Society of India》2017,90(3):273-282
Jaisalmer Formation consists of 360m thick succession of medium to coarse grained sandstones with interbeds of shale, claystone and occasional lignite that rest over Lathi Formation, is the basal part of the Jaisalmer basin. The rocks are exposed amidst desert, low mounds and shallow stone quarries. Sandstones were deposited in shallow marine to deltaic environments. The studied sandstones consist of abundant quartz followed by feldspar, mica, chert, rock fragments and heavy minerals. The study mainly deals with identification of various diagenetic features such as compaction, cementation and porosity evolution. During mechanical compaction rearrangement of grains took place and point, long and suture contacts were formed. The sandstones are cemented by iron oxide, silica overgrowth, carbonate and clay. Porosity has developed due to dissolution of iron, carbonate cement and feldspar grains. Dissolution and alteration of feldspar, lithic fragments and pressure solution were the main source of quartz cements. The sandstones show good amount of existing optical porosity with an average of 7.19%. Porosity reduction is mainly due to early stage of mechanical compaction and subsequent pervasive calcite and iron oxide cementation. Further, porosity reduced due to deposition of clay cement. 相似文献
19.
The bauxites deposits of Kachchh area in Gujarat are investigated to characterize them based on mineralogical and petrographic studies. The major bauxitic mineral in these occurrences is gibbsite, with minor concentration of boehmite and diaspore. Apart from the bauxitic minerals, the other associate minerals are kaolin, calcite, alunite and the iron ore minerals such as hematite and goethite and titanium rich anatase. The iron ore minerals (hematite and goethite) are 10-50microns in size and are disseminated throughout the oolitic and pisolitic bauxitic minerals. At places the goethite exhibits colloform texture. The preservation of basaltic texture in some of the samples indicate that the insitu nature of these bauxites, which are formed by the alteration of calcic plagioclase from the parent basalt. Although, the basalt occurs as the main parent rock for these bauxites, the presence of calcite in some of the samples represent the possibility of having a limestone parent rock at least in some of the bauxite occurrences. 相似文献
20.
鄂尔多斯盆地冯地坑-洪德地区长4＋5段储层以长石砂岩和岩屑长石砂岩为主。本文通过岩心观察、薄片鉴定、扫描电镜、粘土矿物分析等,研究延长组长4＋5段的成岩作用特征,分析其对储层物性的影响,确定储层砂岩的成岩作用阶段。早成岩期的压实作用和多种矿物的胶结作用是造成本区岩石孔隙体积减少的重要因素,而溶解作用尤其是长石的溶蚀作用是储层变好的重要控制因素。 相似文献