Silcrete: an Australian perspective

We know how most rocks are formed. Silcrete is something of an enigma, for although there are many interpretations of the origins of individual silcrete bodies, such as those in the Paris Basin, England, Botswana and central Australia, an overarching hypothesis capable of explaining all occurrences is still to be found. This paper reviews the literature of research on predominantly Australian silcretes as well as reviewing their occurrence, mineralogy, geochemistry and petrology. Silcrete ages and paleoclimatic significance are also reviewed. Most silcretes are formed low in landscapes along fluvial tracts or lakes but, some may form at breakaway margins as a result of lateral groundwater movement. Following silicification and landscape inversion, many silcretes are left high in the landscape. Most silcretes must form in climates where there is an abundance of water, perhaps seasonally, and of organic acids. The age of a silcrete can be constrained by the fossils it may contain; ages of Australian silcretes so established range through most of the Cenozoic. Lacking fossil evidence, sediments of known stratigraphic age that have been silcreted can only provide a maximum age for the silcrete. Many silcretes in eastern Australia are overlain by basalt, but the age of the basalt can only give the minimum age of the silcreted host below it, not of the silcrete. Silcretes commonly exhibit a number of fabrics; externally glerp structures (also called cockade, ropy or botryoidal), and internally pedogenic and geopetal titaniferous grain-cap fabrics. We conclude that silcretes are formed by the precipitation of silica in various forms, almost always along with titania as anatase, at the time of cementation. Anatase occurs either where it is precipitated or by illuviation, commonly becoming concentrated as geopetal caps or coatings on larger detrital framework grains. This implies that the fluids moving the cementing components largely move downward through the silcreted host. Alternating Ti-rich and Ti-poor laminae in the caps show this process can be repetitious.     

Micromorphology and geochemistry of groundwater silcretes in the eastern South Downs, UK

Groundwater silcretes have been recognized recently as major terrestrial silicon sinks and yet their origins are poorly understood. This paper aims to further the understanding of the micro‐fabric, geochemistry and formation of groundwater silcretes, through detailed analyses of silcrete boulders from the South Downs, Sussex, UK. In‐depth petrological investigations of silcrete blocks identified three varieties of silcrete across the study area (saccharoid, hard and pebbly conglomeratic or silcrete breccia), similar to those elsewhere in England. Silcrete fabrics were universally simple and preserved host material structures. Optically continuous quartz overgrowths were the dominant cement and developed on framework grains in the absence of silt‐ and clay‐sized particles. Finer‐grained silica cements occurred in isolated patches and as vein‐ or cap‐like geopetal features. These caps and veins formed through the silicification of illuviated clay‐rich material that entered the host sediment prior to, or in the early stages of, overgrowth formation. Titanium contents were related to the amount of fine‐grained silica and appear to reflect variations in host material chemistry. Subsequent to silicification, the silcretes were altered by at least two phases of ferruginization, characterized by the ingress of iron minerals and partial fabric dissolution or replacement. The study reveals strong similarities in the micromorphology and geochemistry of groundwater silcretes in the study area and those developed in sandy host sediments in neighbouring parts of northwest Europe. Variations that do occur could be explained by differences in the host sediment, geological setting or tectonic history of the respective basins (or sub‐basins), suggesting that there may be a common mechanism for silcrete formation across north‐west Europe. Silcrete development appears to be related to the release of silica accompanying acid leaching of the host material or adjacent strata. In the South Downs, this probably resulted from oxidation of pyrite in the argillaceous and lignitic sediments overlying the host sands. It is envisaged that palaeoenvironmental conditions were of limited importance for silcrete development and that there was no specific ‘era’ of formation, with phased development accompanying landscape evolution through the Neogene into the Pleistocene.     

Aluminosilicate cementation of saprolites,grits and silcretes in Western Australia

Amorphous to poorly crystalline aluminosilicates have been found as cementing agents within saprolites, hardpans and silcretes, particularly in granitic terrains in the Yilgarn Block, Western Australia. The cements range mineralogically from siliceous allophane to a kaolinite‐opal‐CT assemblage probably derived from the allophane. The allophane is non‐crystalline, with no distinctive X‐ray or electron diffraction patterns, and has close optical similarities to opaline silica. It is characterised by Al/Si ratios of 0.35–1.0, with small amounts of adsorbed iron and titanium. It occurs as colloform void and vein fillings, and permeating the kaolinitic matrix of saprolites. The kaolinite and opal‐CT have a similar occurrence, with the kaolinite oriented parallel to colloform and related banding. The aluminosilicate cements are found in saprolite, usually in the upper zones, and in overlying grits and silcretes. At Gabbin, in the central Yilgarn, the grits are up to 10 m thick and have aluminosilicate as the only cement. Although very hard when in situ, the grits tend to disaggregate on exposure and rarely, if ever, crop out. In profiles exposed in breakaways of the Barr‐Smith Range in the northern Yilgarn, the saprolite is overlain by silcretes with a quartz‐anatase‐zircon assemblage as cementing matrix, in turn overlain by alumino‐silicate‐cemented grits. The contact is gradational, and most silcretes and grits contain both types of cement, with the aluminosilicate increasing in abundance upwards. Kaolinitic spherules in sand plains are possibly derived from similar aluminosilicates.     

Basalts and silcretes on the coast near Ulladulla,southern New South Wales

Silcretes on the N.S.W. coast near Ulladulla have long been attributed to. a sub‐basaltic origin, but field evidence is at odds with all variations of the sub‐basaltic hypothesis, and one site shows good evidence that the basalt post‐dates the silcrete. K‐Ar ages averaging 29.7 ± 0.5 Ma from the basalts provide a minimum age for silcrete development in this area. Furthermore, the K‐Ar dates, together with evidence for an erosional rather than tectonic origin of the coastal lowland, demonstrate that the adjacent tablelands reached their present elevation prior to the mid‐Oligocene.     

不同水流速度下温度对奥陶系碳酸盐岩溶蚀速度的影响

为了解不同水流速度下温度对碳酸盐岩溶蚀速度的影响,以自行设计、制造的能够模拟水流条件,并且可同时容纳24个样品的溶蚀试验装置为平台,以淮南张集矿、潞安漳村矿和兖州东滩矿奥陶系灰岩为代表性岩石试样,选取不同温度、水流速度及CO₂压力,进行了溶蚀试验。试验结果显示,在水流速度较低时(16.67 mL/min),环境温度的变化对溶蚀速度的影响比较微小(平均溶蚀变化量为0.000 6 g/cm²)。在水流速度较大时(60 mL/min),温度的改变对溶蚀速度影响较大(平均溶蚀变化量为0.0038 g/cm²)。也就是说在地下水的强径流带,温度对溶蚀速度的影响相对较大,溶蚀速度较快,所以岩溶较发育。     

Relations between shallow cataclastic faulting and cementation in porous sandstones: First insight from a groundwater environmental context

The interplay between fault zone cataclasis and cementation is important since both processes can drastically reduce the permeability of faults in porous sandstones. Yet the prediction of fault cementation in high-porosity sandstone reservoirs remains elusive. Nevertheless, this process has rarely been investigated in shallowly buried faults (<2 km; T°<80 °C) where its sealing capacity could be acquired early in the geological history of a reservoir. In this paper, the macro- and microscopic analysis of a fault zone in the porous Cenomanian quartz arenite sands of Provence (France) shows that silica diagenesis occurs in the most intensely-deformed cataclastic parts of the fault zone. This fault zone shows 19–48% of its total thickness occupied by low-porosity quartz-cemented cataclastic shear bands whose porosities range from 0 – ca. 5%. The analysis of the weathering profile around the fault zone reveals the presence of groundwater silcretes in the form of tabular, tightly silicified concretions cross-cut by the fault. Detailed transmitted light, cold-cathodoluminescence and scanning electron microscopy analyses of the silica cements (from the fault and the silcrete) reveal that all the silica cements originate from groundwater diagenetic processes. This study therefore shows that silica cementation can occur specifically in fault zones and as groundwater silcrete in the shallow context of a groundwater system, generated at the vicinity of an erosional unconformity.     

Miocene silcretes in argillaceous playa deposits, Madrid Basin, Spain: petrological and geochemical features

Four regressive sequences are present in the opaline rocks and related deposits of the Miocene Intermediate Unit of the Madrid Basin. The sequences consist of silty mudstones and argillaceous opals, separated by transitional facies. The silty mudstone consists mainly of dioctahedral smectites, whereas the argillaceous opal is principally opal-CT and variable amounts of sepiolite. In the transitional facies, lamina of dioctahedral smectite co-exist with neoformed opal-CT and sepiolite. Petrological and geochemical features (major, trace and REE elements) indicate that the opaline levels and the transitional facies are related and are a consequence of silcrete formation in an argillaceous playa deposit. The isocon method was used to calculate changes in element concentration associated with silcrete formation. The geochemical data suggest silicification in an arid environment. The silcrete profile occurs four times, possibly as a result of highstand–lowstand fluctuations of the lake level caused by climatic changes. Structures and cements in the silcretes indicate that, although silicification may have commenced at the top of a groundwater table, it continued in the unsaturated zone above the water table.     

Engineering characteristics and uses of duricrusts in Australia

The uses and shortcomings of duricrusts (ferricrete, calcrete and silcrete) in engineering construction (as used for road‐base, aggregate, foundation materials and aquifers) are reviewed. Australian production of these materials represents about one‐third of all unprocessed road‐base and they are especially important as pavement courses for lightly trafficked, low‐cost rural and outback roads. However, duricrusts are regarded as marginal materials at best because of their typically poor grading, particle unsoundness, high fines plasticity, and absorption of water and bitumen. These materials are used because they are available locally in areas that are otherwise lacking in hard rock materials, such as deeply weathered and sedimentary rock terrains. The weathering profiles of which they form part are characterized by high permeability (despite being clay‐rich), variable cementation, low compressibility and a tendency to become weaker with depth. Although the more indurated layers are unrippable, they are also difficult to blast. Pedogenic (nodular) duricrusts were formerly sought for natural road‐base, because they occur widely and require only rudimentary processing. However, well‐cemented groundwater (vadose) duricrusts are now the preferred deposits, even though they require crushing and screening. Ferricrete is the most widely exploited of the duricrusts for engineering purposes, especially in northern and southwestern Australia, although calcrete is important in South Australia and in the Murray Basin. Silcrete is only a minor source of aggregate and road‐base, mainly in western Queensland.     

Thermobarometric modelling of zircon and monazite growth in melt-bearing systems: examples using model metapelitic and metapsammitic granulites

U–Pb age data collected from zircon and monazite are used to draw fundamental inferences about tectonic processes in the Earth. Despite the emphasis placed on zircon and monazite ages, the understanding of how to relate the timing of growth of zircon and monazite to an evolving rock system remains in its infancy. In addition, few studies have presented large datasets of geochronological data from zircon and monazite occurring in the same metamorphic rock sample. Such information is crucial for understanding the growth of zircon relative to monazite in a systematic and predictive manner, as per this study. The data that exist support the generally held conception that zircon ages tend to be older than monazite ages within the same rock. Here experimental data for zircon and monazite saturation in melt-bearing rocks are integrated with phase diagram calculations. The calculations constrain the dissolution and growth behaviour of zircon and monazite with respect to evolving pressure, temperature and silicate mineral assemblages in high-grade, melt-bearing, metasedimentary rocks. Several key results emerge from this modelling: first, that in aluminous metapelitic rocks (i.e. garnet + cordierite + sillimanite assemblages), zircon ages are older than monazite ages in the same rock; second, that the growth rate of accessory minerals is nonlinear and much higher at and near saturation than at lower temperatures; and third, that the difference in zircon and monazite ages from the same rock may be ascribed to differences in the temperature(s) at which zircon and monazite grow rather than differences in closure temperature systematics. Using our methodology the cooling rate of granulites from the Reynolds Range, central Australia, have been constrained at ∼4 °C Myr⁻¹. This study serves as a first-pass template on which further research in applying the technique to a field study can be based.     

准噶尔盆地腹部深埋储层次生孔隙成因机理研究

准噶尔盆地腹部勘探目的层埋深大,一般在5 500～6 000 m左右,属于深埋储层。在对大量薄片分析鉴定的基础上,运用扫描电镜、阴极发光和X衍射粘土分析等手段,对研究目的层的孔隙类型和成因机理进行了研究。研究发现孔隙类型以次生溶蚀孔隙为主。中晚侏罗世发育的车莫古隆起导致非持续埋藏的成岩背景,由于中途开启地层抬升暴露,酸性大气淡水对粒间方解石胶结物淋滤溶蚀,产生次生溶孔;白垩系之后再度埋藏发生有机酸内幕溶蚀作用。由于地层抬升剥蚀导致成岩阶段滞后,勘探目的层现今处于晚成岩A1亚期是次生孔隙保存的重要条件。     

Geography in Australian education

Geography in Australia has a heritage that is strongly British, but more recently has been influenced from other parts of the world, such as North America and New Zealand. Its popularity has fluctuated and it is now under threat as a separate subject in the compulsory years of schooling. In higher education, geography has retrieved lost ground to be a popular area of study, but not a research area in the current national priorities. Geography plays a focal role in the general education of Australians. It is a medium for education involving the education of people, about, in, and for the society and environment in which they live. Through education, geography will enable people to explore their life-roles as learners, social beings, recreators, producers, consumers and citizens. It will develop in people distinctive knowledge, thinking processes, attitudes and values, and encourage participation in social and environmental actions. Teachers in secondary and higher education have differing and distinctive roles. Being a geographer in Australia does have benefits including: working in an identifiable area of knowledge maintaining a bridge across the physical and social sciences; the promotion of inquiry approaches and as a focus for the various adjectival educations that have emerged. These are tempered by challenges such as: threats from emerging disciplines, current national research priorities and the movement to social science education. Therefore, promotion of geography in Australia needs to be much more forceful than it has until now. The work of groups such as the Institute of Australian Geographers and the Australian Geography Teachers' Association needs to be co-ordinated more closely to develop a strong lobby for geography in Australian education.     

塔中地区奥陶系海相碳酸盐岩储层的溶解动力学特征

选取塔中地区奥陶系海相碳酸盐岩样品进行了模拟实验,以研究其在表生岩溶作用下的溶解动力学特征.实验分别在30,50℃下,用pH值为3～6的盐酸溶液,恒温水浴加热进行.结果表明:4种样品溶解速率的相对大小依次为:灰白色灰岩＞砂屑灰岩＞粗晶白云岩＞中粗-细晶白云岩,且溶解速率均随着温度的升高而增大,随着pH值的增大而减小.但随着外界环境的变化,溶解速率的变化略有差异.造成这种差异的原因可能是样品中的硅酸盐杂质、晶体颗粒的大小以及实验过程中产生的CO2的影响.由实验结果推测可知,对于塔中地区以表生岩溶作用为主形成的奥陶系海相碳酸盐岩储层,灰岩储层的储集性能可能优于白云岩储层;对于以埋藏岩溶作用为主形成的奥陶系海相碳酸盐岩储层,白云岩储层的储集性能可能优于灰岩储层.     

Hydrothermal Alteration Zoning and Kinetic Process of Mineral-Water Interactions

This study reports the kinetic experimental results of albite in water and in KCI solution at 22 MPa in the temperature range of 25 to 400℃. Kinetic experiments have been carried out in an open flow-through reaction system (packed bed reactor). Albite dissolution is always incongruent in water at most temperatures, but becomes congruent at 300℃ (close to the critical point 374℃). At temperatures from 25 to 300℃, the incongruent dissolution of albite is reflected by the fact that sodium and aluminum are easily dissolved into water; from 300 to 400℃ it is reflected by silicon being more easily dissolved in water than Al and Na. Maximum albite dissolution rates in the flow hydrothermal systems have been repeatedly observed at 300℃, independent of flow rates.The kinetic experiments of albite dissolution in a KCl aqueous solution (0.1 mol KCl) indicate that the dissolution rate of albite increases with increasing temperature. Maximum silicon release rates of albite have been observed at 400℃, while ma     

Subsea-floor replacement in volcanic-hosted massive sulfide deposits

Recent research on volcanic-hosted massive sulfide (VMS) deposits indicates that syngenetic subsea-floor replacement ores form an important component of many deposits. In the context of VMS deposits, subsea-floor replacement can be defined as the syn-volcanic formation of sulfide minerals within pre-existing volcanic or sedimentary deposits by infiltration and precipitation in open spaces (fractures, inter- and intra-granular porosity) as well as replacement of solid materials.There are five criteria for distinguishing subsea-floor replacement in massive sulfide deposits: (1) mineralized intervals are enclosed within rapidly emplaced volcanic or sedimentary facies (lavas, intrusions, subaqueous mass-flow deposits, pyroclastic fallout); (2) relics of the host facies occur within the mineral deposit; (3) replacement fronts occur between the mineral deposit and the host lithofacies; (4) the mineral deposit is discordant to bedding; and (5) strong hydrothermal alteration continues into the hanging wall without an abrupt break in intensity. Criteria 1–3 are diagnostic of replacement, whereas criteria 4 and 5 may suggest replacement but are not alone diagnostic. Because clastic sulfide ores contain accessory rock fragments collected by the parent sediment gravity flow(s) during transport, criteria 2 can only be applied to massive, semi-massive, disseminated or vein style deposits, and not clastic ores.The spectrum of VMS deposit types includes deposits that have accumulated largely subsea-floor, and others in which sedimentation and volcanism were synchronous with hydrothermal activity, and precipitation of sulfides occurred at and below the sea floor over the life of the hydrothermal system. Deposits that formed largely subsea-floor are mainly hosted by syn-eruptive or post-eruptive volcaniclastic facies (gravity flow deposits, water-settled fall, autoclastic breccia). However, some subsea-floor replacement VMS deposits are hosted by lavas and syn-volcanic intrusions (sills, domes, cryptodomes). Burial of sea-floor massive sulfide by lavas or sediment gravity flow deposits can interrupt sea-floor mineralization and promote subsea-floor replacement and zone-refining.The distance below the sea floor at which infiltration and replacement took place is rarely well constrained, with published estimates ranging from less than 1 to more than 500 m, but mainly in the range 10–200 m. The upper few tens to hundreds of metres in the volcano-sedimentary pile are the favoured position for replacement, as clastic facies are wet, porous and poorly consolidated in this zone, and at greater depths become progressively more compacted, dewatered, altered, and less amenable to large scale infiltration and replacement by hydrothermal fluids. Furthermore, sustained mixing between the upwelling hydrothermal fluid and cold seawater is regarded as a major cause of sulfide precipitation in VMS systems, and this mixing process generally becomes less effective with increasing depth in the volcanic pile.The relative importance of subsea-floor replacement in VMS systems is related principally to four factors: the permeability and porosity patterns of host lithofacies, sedimentation rate, the relative ease of replacement of host lithofacies (especially glassy materials) and early formed alteration minerals during hydrothermal attack, and physiochemical characteristics of the hydrothermal fluid.     

重庆中梁山碳酸盐岩溶蚀速率对季节的响应研究

在重庆市中梁山岩溶槽谷,选取林地、园地、耕地和菜地4种不同土地利用类型,通过野外下三叠统嘉陵江组白云质灰岩石试片的溶蚀试验分析不同土地利用方式下溶蚀速率对季节的响应关系。结果表明:不同土地利用方式将造成土壤性质发生不同的变化,进而对岩石的溶蚀速率产生明显的影响。但无论是从夏半年还是从全年来看,试片的溶蚀速率的大小变化均表现为:林地>菜地>耕地>园地。夏半年在全年的试片溶蚀作用过程中贡献较大,其绝对溶蚀量占全年比例都大于50%;除林地、菜地和园地土下50cm试片外,其余试片的夏半年溶蚀速率都大于全年溶蚀速率。究其原因,主要是由于夏半年气温高,降水量大,使土壤中CO2和水分等增加,从而有利于岩溶作用的进行      

Granite weathering and silcrete formation on the Yilgarn Block,Western Australia

Weathering profiles developed on granitic rocks, exposed in the breakaways of the Barr‐Smith Range in the N of the Yilgarn Block of Western Australia, consist of kaolinitic saprolites merging upwards into silcrete, sandstone and grit. The sandstones and silcretes may also form columns or dykes, penetrating downwards into the saprolite. The silcretes are cemented by quartz and anatase, with zircon (QAZ‐cement), and‐the sandstones are cemented by aluminosilicates, either apparently amorphous (as siliceous allophane) or partly crystalline, as kaolinite and opaline silica. Transitional zones between silcretes and sandstones have all cement types. The profiles are characterized by low concentrations of alkalis and alkaline earths and most metals. The QAZ‐silcrete horizons may contain over 3% TiO₂ and 1000 p.p.m. Zr. The profiles evolved through at least four stages: (i) Formation of the deep saprolite‐sand weathering profile by kaolinization of feldspar and mica at depth, and the solution of kaolinite near the top of the profile, causing settling of resistant quartz grains, (ii) Precipitation of QAZ‐cement, the TiO₂ and SiO₂ being derived partly by lateral migration from upslope. (iii) Precipitation of aluminosilicates, in the sandstone and the saprolite. (iv) Erosion and exposure of the profiles by pedimentation. A similar profile occurs further S, at Gabbin, but no QAZ‐silcrete is present and the only exposures are in exploration pits. The kaolinitic saprolite‐quartz sand profiles probably formed under humid conditions, as the equivalents of ferruginous laterite developed on more basic rocks nearby and of lateritic bauxite in the Darling Range. However,’ the sand was a surface horizon and there is no evidence that there was ever a ferruginous zone at these sites. The sequential precipitation of QAZ‐ and aluminosilicate‐cements was probably, a response to increasing aridity and reduced groundwater flow. Aluminosilicate‐cemented materials tend to disaggregrate on exposure but they are probably more abundant than the more prominent QAZ‐silcretes.     

半干旱区岩溶碳汇原位监测方法适宜性研究

选择正确的方法准确计算北方干旱半干旱岩溶区的岩溶碳汇量, 有助于提高我国岩溶碳汇效应估算精度和改进全球碳循环模型。利用水化学径流法和标准溶蚀试片法对山西马跑神泉域的岩溶碳汇量进行了计算, 结果表明, 标准溶蚀试片法计算出的流域碳汇量和碳汇强度为386.15 t/a和1.821 t/(km²·a), 水化学径流法的结果为2 084.08 t/a和9.83 t/(km²·a), 试片法计算结果仅为水化学径流法的1/5。试片溶蚀速率和土壤无机碳质量分数呈负相关关系, 进一步表明土壤无机碳质量分数高(是有机碳质量分数的2.85~5.06倍)是造成试片法计算结果偏小的主要原因:高含量的无机碳在半干旱气候条件下容易沉积, 从而使试片溶蚀速率偏小;流域边界清楚, 水化学和流量易于监测, 利用水化学径流法计算岩溶碳汇强度结果更为准确。因此, 在半干旱地区, 计算岩溶碳汇效应宜采用水化学径流法。     

山西王家岭矿区奥陶系碳酸盐岩溶蚀规律研究

为研究王家岭矿区奥陶系碳酸盐岩的溶蚀规律,模拟造成差异性溶蚀的主要因素进行了实验。在常温常压、溶蚀液碳酸水的pH值为6.5～6.9、每次溶蚀时间控制在24h左右的条件下,对矿区不同层段的碳酸盐岩进行溶蚀实验。实验发现,碳酸盐岩的成分和结构是影响溶蚀指标的重要因素,比溶蚀度和比溶解度总体趋势是白云岩灰岩膏岩;不溶物含量的增大使比溶蚀度和比溶解度下降,机械破坏量呈非线性增加;相同情况下方解石溶解速度快于白云石2～3倍。该实验结果为矿区进行水文地质研究提供了基础数据。     

Sequence in Australian coal seams

An embedded Markov model is used to test microlithotype analyses of subsections of a wide range of Australian coal seams for the presence of nonrandom sequences of lithologies. The data for individual seams, transformed to give five states (four states if dirt bands are excluded),were summed into geologically and geographically distinct groupings. The results suggest that dirt bands form an essential part of the sequences and that partial or complete cyclicity is present in many seam groupings. The cyclicity is either asymmetric or partially symmetric with the vitrite +clarite content of the coal decreasing upwards within each cycle. A new cycle is marked either by a sharp reversion, or by a slightly gradational reversion, to a vitrite +clariterich lithology. This reversion may or may not be preceded by a dirt band. In virtually all groupings, a vitrite +clarite-rich lithology is the most likely type after a dirt band. The sequences are similar to those that have been described in European coals and it seems probable that the presence of intraseam, cyclic sequences is a normal, rather than an unusual condition, within coal seams. This cyclicity is a response to changes in the sedimentation balance. These changes are probably due in large part to processes originating within the peat-forming environment but processes external to this environment are also likely to produce cyclic sequences of coal lithologies.     

三峡地区碳酸盐岩化学组分与溶蚀速率的响应关系

文章通过室内静水溶蚀实验测定了三峡地区香溪河流域震旦-三叠系碳酸盐岩的化学溶蚀速率,探讨了碳酸盐岩的化学溶蚀速率对岩石化学组分的响应关系,为区域岩溶量化研究与地层含水性评价等提供了科学依据。研究结果表明:较纯碳酸盐岩的溶蚀速率受到CaO、SrO的促进作用和MgO的抑制作用共同控制,而这三者对纯灰岩的溶蚀速率影响较小;碳酸盐岩中的酸不溶物对化学溶蚀过程呈现出抑制的趋势。碳酸盐岩的化学溶蚀速率受到多化学组分的共同影响,综合决定了碳酸盐岩的可溶性。