Ken G Grimes

Sand speleothems have formed in sea caves at Loch Ard Gorge, Victoria, Australia, by the localised precipitation of calcium carbonate in loose sand that fills the caves. Calcite-saturated waters have entered the caves from the surrounding porous limestone, either dripping onto the sand, or seeping directly into it from the walls. Removal of the uncemented sand has exposed the cemented formations which have shapes analogous to those of conventional stalagmites, stalactites and shelves.

A small but unusual cave has formed within a large dyke that intrudes a scoria cone at the summit of Mount Fyans, western Victoria. Draining of a still-liquid area, after most of the dyke had solidified, left an open cavity. Features within the cave mimic those of conventional lava caves, and suggest that the lava levels oscillated within the cave. Some smaller fingers of lava that intruded the scoria also have hollow, drained, cores.

An introduction to karst hydrological terms and concepts is followed by a discussion of the factors that must be considered when classifying or studying karsts. These are then applied to a broad overview of the hydrology of the main Australian karsts.

Microkarren are the smallest class of visible karren. They are finely-sculptured solutional forms, typically recognisable within a one centimetre grid. They come in a variety of patterns, of which fields of moderately to strongly sinuous microrills about 1mm wide and several decimetres long are the most conspicuous type. A descriptive terminology is suggested. Their genesis is uncertain, but appears to involve solution by thin films of water (dew, sea-spray or light rain) with surface-tension effects. In Australia their best development seems to be in the tropical monsoon (seasonally dry) and arid areas. However, these cryptic forms are poorly recorded and it is too early to make definite statements about their distribution. This note is a request for people to watch for them and report any sightings.

Surveying and Sketching are two distinct and complimentary operations in the making of a cave map. * Surveying involves measuring a control framework through the cave using tape, compass, etc. * Sketching involves drawing the walls and other detail to scale, using the surveyed framework as control. When the two processes are combined, they produce a Map. Unfortunately, many cave mappers tend to concentrate on one to the detriment of the other and so produce a sub-standard map. This poster concentrates on the sketching side of the mapping operation.

Summarizes some published information on an extensive, but little studied, area of palaeokarst developed on Proterozoic dolomites in the East Pilbara. The area extends from Mount Newman north to the Rippon Hills. The palaeokarst unit is shown on the 1:250 000 geological maps of the region as the (multi-aged?) Pinjian Chert Breccia that has developed by karstic weathering of the Proterozoic Carawine Dolomite. Palaeokarst features may also be associated with other Proterozoic dolomite units in the Pilbara region, such as the Wittenoom Dolomite. Some of the manganese ore bodies in the region are associated with palaeokarst cavity-fills. Some more recent karst dolines and caves also occur.

Most documented lava caves are large, linear or anastomosing tubes formed by roofing of lava channels or development of major feeder tubes within a flow. However an increasing number of small shallow caves is being recorded that have simple to complex patterns of interconnected low chambers and small passages that form by a different process. In reviews of active volcanoes in Hawaii, Peterson & others (1994) and Hon & others (1994) proposed two distinct models for the formation of lava tubes: firstly by the roofing over of linear surface lava channels; and secondly by the draining of still molten material from beneath the solidified crust of pahoehoe flow lobes. This paper will concentrate on the second type: the smaller, but occasionally complex, caves formed by localisation of flow beneath the crust of thin flow lobes or sheet-flows, and subsequent partial draining - as illustrated in Figure 1. More recently Halliday (1998a & b) has described two types of small lava cave: His &quo...

Self and Mullan (1996) wish to redefine the concepts "karst" and "pseudokarst" in terms of purely physical characteristics rather than their traditional meaning, which involves both landform and process. It is argued here that their usage of "karst" would be more appropriately termed "karst terrain" and that "karst" is best kept as a -combination of terrain and process, with a process-based division into "true" karst and "pseudokarst" where this is feasible. If a separate term is wanted for features such as talus caves, which have a distinctive morphology as well as a separate process, then "quasi karst" is suggested.

Christmas Island is a tropical island (Latitude 10°30'S), in the Indian Ocean, northwest of Australia. This poster concentrates on the karst features and their management. The island is a basaltic volcano with a limestone capping. The interaction of uplift and old sea-levels has left terraces cut into the steep sides of the island. The central plateau is phosphate over a pinnacled epikarst limestone surface, with the crest of the volcanic surface about 30-40 m down. The climate is tropical monsoonal with an annual rainfall of over 2000mm. The coastal cliffs which circle most of the island have strong notches cut at sea-level, and well-developed hackly phytokarst sculpturing of the rocks. In one place spring-fed streams running across the Shore Terrace have cut narrow canyons, known locally as The Dales. Large subsoil pinnacles occur on the plateau and terraces and have been exposed by mining. Most of the big caves are at sea level and entered from the base of the coastal cliffs....

Two alternative interpretations exist for the pipes and other features of the so-called 'Petrified Forest' at Cape Duquesne, west of Bridgewater Bay, Victoria. The early tree-mould hypothesis of Boutakoff (1963), which is still advocated by the new interpretation signs at the site, is rejected in favour of more recent suggestions that interpret the features as solution pipes formed by focussed vertical water flow through the porous calcareous sands (aeolianites). The focussing of the flow may be spontaneous and associated with patchy cementation of the hardpan of the soil, or it may be guided by other factors such as concentrated stem-flow beneath trees, or along taproots, or the pooling of water in hollows in exposed hardpans.

In syngenetic karst speleogenesis and lithogenesis are concurrent. Eogenetic karst and soft-rock karst are closely related terms. The distinctive features of syngenetic karst are: shallow horizontal cave systems; a general lack of directed conduits (low irregular chambers occur instead); clustering of caves at the margins of topographic highs or along the coast; paleosoil horizons; vertical solution pipes which locally form dense fields; extensive breakdown and subsidence to form collapse-dominated cave systems, a variety of surface and subsurface breccias and locally large collapse dolines & cenotes; and limited surface sculpturing (karren). These features are best developed in host sediments that have well developed primary porosity and limited secondary cementation (and hence limited mechanical strength). Certain hydrological environments also assist: invading swamp waters or mixing at a well developed watertable; or, near the coast, mixing above and below a freshwater lens float...

Christmas Island (in the Indian Ocean) is an uplifted, composite, reef-carbonate island with a volcanic core. The coast is mostly cliffed and rises steeply via a series of terraces to a central phosphate-blanketed plateau. In spite of the high rainfall, there is little surface water as drainage is underground and karstic. Water is initially stored in an epikarst aquifer, then follows the limestone/volcanic contact out to the island edge to emerge at major conduit springs. These springs are mostly at or below sea level, but some perched springs occur where the volcanic rocks appear at the surface. Caves occur at the present coast, as uplifted coastal caves, on the plateau, and there are a few pseudokarst caves. Cave development involves mixing zones between fresh and sea water in the coastal zone, and between vadose and phreatic waters perched on the volcanic rocks beneath the plateau. Cave locations and forms are controlled by the rock structure (especially jointing), the location o...

In addition to carbonate karsts, the Judbarra / Gregory National Park of tropical northern Australia has karst and paleokarst features associated with Proterozoic sandstone units. On a sandstone plateau in the Newcastle Range, there are several large collapse dolines formed in the Proterozoic Jasper Gorge Sandstone. As there is a carbonate unit, the Proterozoic Campbell Springs Dolostone, lying about 110 m beneath the plateau surface, these sinkholes may be subjacent karst features resulting from the upward stoping of large cave chambers. In the Far Northern area of the Judbarra Karst Region, areas of chert breccia are shown on the geological maps, and linear bodies of brecciated sandstone are inset into the carbonate beds of the Skull Creek Formation. The sandstone is derived from the Jasper Gorge Sandstone, which overlies the Skull Creek Formation in adjoining areas. The breccia is interpreted as paleokarst of uncertain age resulting from subsidence of the sandstone into karst tre...

The abstract given below is abbreviated here, see "Full Text" for the full published conference abstract text + Poster page. When dealing with karst-like features on non-limestone rocks, there is a lack of agreement on the terminology and classification. The term "karst" is used to refer to both the distinctive landforms that occur on limestones, and also the process (solution) that forms then. When discussing classifications we need to distinguish between: * Karst landforms: caves, underground conduit drainage, sinkholes, karren, etc. * Karst processes: dominantly solution; but other processes, such as hydraulic erosion in stream caves, can also contribute. * Karst rocks: the carbonates (limestone and dolomite), but other strongly soluble rocks such as gypsum and halite (salt) need to be considered in the following discussion. * Karst, in the strict sense, involves all three of the above. * Parakarst is generally defined as karst-like landforms formed by solutio...

In the monsoon tropics of northern Australia, Bullita Cave is the largest (120 km) of a group of extensive, horizontal, joint-controlled, dense network maze caves which are epikarst systems lying at shallow depth beneath a well-developed karrenfield. The Judbarra Karst and its caves are restricted to the outcrop belt of a thin bed of sub-horizontal, thinly interbedded dolostone and calcitic limestone – the Supplejack Member of the Proterozoic Skull Creek Formation. Karst is further restricted to those parts of the Supplejack that have escaped a secondary dolomitisation event. The karrenfield and underlying cave system are intimately related and have developed in step as the Supplejack surface was exposed by slope retreat. Both show a lateral zonation of development grading from youth to old age. Small cave passages originate under the recently exposed surface, and the older passages at the trailing edge become unroofed and /or destroyed by ceiling breakdown as the, by then deeply-in...

Observations of active lava flows has shown that there are two distinct ways in which lava tubes or caves form: 1: Roofing of surface lava channels. This can happen in three ways (e.g. Peterson et al, 1994), see panel 2. 2: Sub-crustal drainage within thin lava lobes or sheets. (e.g. Peterson et al, 1994 & Hon et al, 1994), These evolve from isolated chambers and proto-tubes into multi-chamber and multilevel systems. See panels 3-5 . Both Types (roofed channels and sub-crustal systems) evolve over time into large linear feeder tubes, and the evidence of their original formation may be destroyed. Draining of the liquid lava from these tubes will leave open caves. Most tubes never drain and become blocked with solid basalt. * Open Volcanic Vents are a rare type of cave formed by the draining of the lava back into the source vent. * Caves can also form in tectonic fissures. * Weathering of ash and lava can also form secondary caves.

In the monsoon tropics of northern Australia, a strongly-developed karrenfield is intimately associated with extensive underlying epikarstic maze caves. The caves, and the mesokarren and ruiniform megakarren are mainly restricted to a flat-lying, 20 m thick, unit of interbedded limestone and dolomite. However, microkarren are mainly found on the flaggy limestones of the overlying unit. These are the best-developed microkarren in Australia, and possibly worldwide. A retreating cover results in a zonation of the main karrenfield from a mildly-dissected youthful stage at the leading edge through to old age and disintegration into isolated blocks and pinnacles at the trailing edge. Cave undermining has formed collapse dolines and broader subsidence areas within the karrenfield. Tufa deposits occur in major valleys crossing the karrenfield. The karrenfield shows some similarities to other tropical karren, including tsingy and stone forests (shilin), but in this area there has not been an...

Pendants, pillars and concretions of cemented sand are exposed in a dune limestone cave in southwest Western Australia. These are the result of focussed flow of carbonate-saturated water through the sand in a very early stage of eogenetic diagenesis. Vertical vadose fingered flow has cemented the pillars and pendants, and horizontal phreatic flow has produced a layer of elongated concretions along a bedding plane. Later cave development has exposed the cemented sand bodies.

The Gambier Karst Province is an extensive area of Tertiary and Quaternary limestones in southeastern South Australia and western Victoria. This area of "soft rock" caves is developed on youthful, weakly-consolidated porous limestones and is syngenetic in part. The caves are characterized by cap rock effects, solution pipes, extensive low horizontal phreatic mazes, abundant collapse modification and extensive large flooded systems. The cenotes, large water-filled collapse dolines, are unique within Australia. There are large springs rising from flooded caves at the coast and offshore. Evolution of the caves is partly tied to the rise and fall of the sea, and associated water tables, during the Quaternary. The karst aquifer is one of the best in Australia, but careful management will be needed to maintain that quality. Management is also required to maintain the quality of the surface karst features, the caves and their environment.

In syngenetic karst speleogenesis and lithogenesis are concurrent: caves and karst features are forming at the same time as the loose sediment is being cemented into a soft, porous rock. “Eogenetic karst” and “soft-rock karst” are closely related terms for features developed in soft, poorly-consolidated limestones.
The distinctive features of syngenetic karst are: shallow horizontal cave systems; a general lack of directed conduits (low irregular chambers occur instead); clustering of caves at the margins of topographic highs or along the coast; paleosoil horizons; vertical solution pipes which locally form dense fields; extensive breakdown and subsidence to form collapse-dominated cave systems; a variety of surface and subsurface breccias and locally large collapse dolines and cenotes; and limited surface sculpturing (karren).
These features are best developed in host sediments that have well developed primary matrix permeability and limited secondary cementation (and hence limited mechanical strength), for example dune calcarenites. Certain hydrological environments also assist: invading swamp waters or mixing at a well-developed watertable; or, near the coast, mixing at the top and bottom of a freshwater lens floating on salt water. Where these factors are absent the karst forms tend to be more akin to those of classical hard-rock or telogenetic karst.

Solution pipes (or dissolution pipes), as described here, are the small, vertical, smoothly cylindrical pipes found in soft (poorly cemented) porous calcarenites, and usually associated with a modern or ancient soil or a calcrete band. They are typically about 0.5 m wide and 2-5 m deep, though there is significant variation. Pinnacles are associated features, but less common.

Karren in tropical Australia are strongly developed at all scales from microkarren to giant grikes and pinnacled towers, but with decreasing intensity and variety as one moves into the drier climates of the interior. However, the local effects of lithology, structure, cover and denudation history can create considerable variation.

Laterite karst is a special type of silicate karst (formed in silicate rocks such as sediments or granite) that in turn is a type of parakarst (solution of non-carbonate rocks). However, the chemical and physical processes involved in the formation of laterites, and deep weathering profiles in general, are quite complex.

The South-East Karst Province of South Australia is an extensive area of low relief with dolines, cenotes, uvalas, and a variety of cave types developed in the soft, porous, flat-lying Tertiary Gambier Limestone and also as syngenetic karst in the overlying calcarenite dunes of the Pleistocene Bridgewater Formation. The most spectacular surface karst features are the large collapse dolines, especially those that extend below the water table to form cenotes. Shallow swampy hollows occur in superficial Quaternary sediments. These are an enigmatic feature of the Bool Region, where all gradations appear to occur between definite karst dolines and nonkarstic hollows. Some depressions may be polygenetic—involving a combination of: (1) primary depositional hollows on coastal flats or in dune fields, (2) deflation, and (3) karst solution and subsidence. There are extensive underwater cave systems in the southern part of the province, and the bulk of the cave development there may well lie below the present water table, although these systems would have been at least partly drained during the lower sea levels of the last glacial period. Systematic variations within the province reflect differences in the parent rock types, the extent and nature of the cover and, most importantly, the hydrology—in particular the depth to the water table and its gradient.

The flat-lying sandstone areas of tropical north Australia have a range of interesting landforms that include caves, dolines, and other karst-like features, and also spectacular ruiniform terrains. These landforms can be classed as silicate karst, parakarst, pseudokarst and non-karst (but the last have ruiniform areas that have considerable scenic and scientific interest).
    Caves range from small rock shelters through small tunnels and large tubes which may have dark zones, to larger stream caves (both active and abandoned) and complex maze systems. Dolines are mainly collapse or subsidence features, and some may be due to subjacent karst effects. Blind valleys and stream sinks are associated with the stream caves. Small-scale features include solution pans and runnels, sculptured walls that resemble karren, and sandstone pillars within some caves or exposed in cliffs. The pillars appear to be a type of diagenetic cementation by focussed vertical water flow.
    Ruiniform features are giant grikefields, stone cities and stone forests which result from structurally controlled weathering and erosion. At the edge of a plateau developed on flat-lying sandstones one finds that erosion first attacks the joints, widening them to form grikes which grow larger and deeper to become giant grikefields. As the grikes enlarge further they widen at the expense of the higher areas between them to make stone cities. Eventually the low ground dominates and we get a stone forest and finally scattered pinnacles on a low-level pavement. Stone cities are referred to by the tourism industry as “lost cities”. These features are analogous to karst grikes, pinnacles and towers, but solution is not the main process involved. Whilst solution of silicate cement may be involved in the original weathering process (along with oxidation of iron and aluminium compounds, and clay mineral formation), the majority of material is subsequently removed by fluvial processes, or, less commonly, by wind. Grikes etc on both limestone and sandstone are best classed as ruiniform, rather than “karst-like”, as the structural control is more important than the processes of chemical and physical weathering that are involved.
    Many important sites have developed in Proterozoic sandstones and quartzites. Whalemouth Cave in WA is a particularly large and spectacular stream cave in sandstone. On the plateau above the cave several blind valleys and stream sinks can be seen from the air. In the NT there appear to be large and complex horizontal maze cave systems at Kakadu and possibly at Bunju, but these have not been studied in any detail and access is difficult. Also in the NT, large collapse dolines, some with water-table lakes (i.e. cenotes), occur in sandstones of eastern Arnhem Land, near Borroloola and on the Newcastle Range in the Gregory/Judbarra NP. Again, access is difficult and the genesis is uncertain as the host sandstones either have a carbonate cement or are underlain by limestone units. In Queensland, Widdallion cave in the Lawn Hill (Boodjamulla) NP is a stream cave similar to, but much smaller than Whalemouth. Further east in Queensland, Mesozoic sandstones have a range of features. A surface stream within the grikefields of Cobbold Creek Gorge has several underground segments. In the sandstone ranges of central Queensland there are many rock shelters, and also large tubes and small tunnel caves. The main interest there is in the extensive small horizontal tubes, and three-dimensional networks of smaller tubelets, even though they are too small for human access.

Laterite karst refers to karst-like landforms formed in deep weathering profiles (especially laterites, but also in bauxite and silcrete profiles) by a combination of silicate solution (parakarst) and other processes (pseudokarst).
    Deep weathering involves the intensive chemical weathering of the minerals in a rock over a long period of time. The minerals are converted to new forms which may be soluble, and can be removed in solution; or may be softer, such as clay minerals; or crumbly, such as residual sand grains, and can be washed out of the rock by flowing water, or removed by wind or gravity – producing cavities and other karst-like forms. Localised precipitation of the dissolved material forms duricrusts – these generate mesas and scarps (occasionally runiform), and provide a solid roof beneath which caves can form.
    Laterite karst is most common in tropical regions but examples can also occur in temperate climates if deep weathering profiles exist.
    Laterite karst shows a particularly strong analogy with the syngenetic karsts (in soft porous calcarenites) as both have simultaneous solution and cementation of the "rock" and show the influence of caprocks (duricrusts) on cave development.
    The karst-like landforms range through all scales: Broad-scale features include fields of shallow dolines, or "pans", up to 2 km across, which may grade into dambos; together with rarer collapse dolines. Care is needed to distinguish the laterite hollows from other types formed by deflation or by subjacent karst subsidence. Meso-scale features include caves (mostly small rock shelters, but some longer tunnels and complex mazes), and fields of solution pipes and pinnacles, and irregular "epikarst" surfaces. At the smallest scale one finds centimetric tubelets and vughs, and breccias in pipes, pockets or horizontal bands.
    The vuggy and conduit porosity can host significant shallow aquifers, which might exhibit problems similar to karst aquifers.

Microkarren (Rillensteine) are the smallest class of visible karren. They are finely-sculptured solutional forms on bare limestone surfaces, recognisable within a one centimetre grid. They form various patterns, the commonest being linear microrills 1mm wide and several decimetres long.
  Laudermilk & Woodford (1932, Amer. J. Sci., 23: 135-154.) described four types, but their descriptions are confusing and don't cover the full range. A broader terminology is suggested (Grimes, 2007: Helictite 40(1): 21-23.):
* Microrills: narrow, parallel grooves; straight, sinuous or tightly meandering. With increasing branching density, they grade to...
* Micro-networks: branched rills form a network. With increasing branching they grade to...
* Micro-teeth: a dense network of grooves separating isolated sharp, conical or faceted teeth.
* Micro-pits: hemispherical to conical pits occur in a wide range of sizes (1 - 20 mm wide, approaching normal "rain-pits"). Possibly polygenetic, and not all microkarren.
* Micro-pans: Shallow pits, 5-10 mm wide. Flat to curved floors contain fine pits or teeth. Scattered clusters are superimposed on prior microkarren. An unconfirmed origin might be solution beneath faecal pellets.
* Micro-notches: irregular V-section notches following cracks in the rock (a micro-splitkarren) – a broad range of sizes.
* Micro-tessellations: networks of U-section notches disrupt prior microkarren, apparently etching a superficial crazing pattern.
* Micro-decantation rills: run down vertical sides of cobbles, becoming smaller as they descend.
  The genesis of microkarren is uncertain, but may involve solution by thin films of water (dew, sea-spray or light rain) with surface-tension effects. Some forms, e.g. micro-pits, may be polygenetic.

In Australia their best development seems to be in tropical monsoon (seasonally dry) and arid areas. Elsewhere, they have been recorded from the arctic (Greenland) to the tropics (Philippines) and from dry to humid (2500 mm) rainfalls. However, these cryptic forms are poorly recorded and it is too early to make definite statements about their distribution.