Cave Levels Research Articles

Land Snails from St. Elzear Cave, Gaspé Peninsula, Quebec: Antiquity ofCepaea Hortensisin North America

ABSTRACT The presence of the European land snail, Cepaea hortensis (Muller, 1774), in archaeological deposits indicates its existence in North America before the arrival of post-Columbus European settlers. We address whether this species arrived in North America before Viking explorers. Evidence from cave deposits in St. Elzear de Bonaventura Cave on the Gaspe Peninsula, Quebec, suggests that C. hortensis appeared in North America prior to arrival of the Vikings about 1000 YBP and possibly more than 7850 YBP. The presence of the larger snail species Anguispira alternata (Say, 1816) and Neohelix albolabris (Say, 1817) in cave levels representing tundra to taiga conditions, coupled with their absence as far north as modern taiga, suggests that some large snails may not disperse quickly enough to occupy all favorable habitat made available by warming climates.

Evolution of salt diapir and karst morphology during the last glacial cycle: Effects of sea-level oscillation, diapir and regional uplift, and erosion (Persian Gulf, Iran)

Marine, fluvial and cave sediments, and karst phenomena were studied and dated by 14C, U-series, and OSL methods to determine the evolution of the Namakdan diapir and the world's longest salt cave (3N Cave) during the Holocene and the Last Glacial. Sea-level oscillations, the uplift rate of the diapir and its surroundings, and erosion are the main factors influencing the diapir morphology. Although the diapir uplift rate has been constant for the last 50 kyr (∼ 4 mm/yr at a distance 600 m from the diapir edge), the uplift rate decreases with the distance from the diapir center. Drag-induced host rock deformation extends for ∼ 300 m from the outside edge of the diapir, and host rocks in this zone have an uplift rate of 0.4–0.6 mm/yr, which is 2–3 times greater than the regional uplift rate. Based on known sea-level oscillations, radiometric dating, and geological evidence, the Namakdan diapir was repeatedly flooded by sea water between 130 and 80 kyr BP. Submarine residuum composed mainly of gypsum and dolomite formed cap rock on the diapir. After ∼ 80 kyr BP, surficial drainage network and karst development started. Blind valleys and their corresponding cave systems evolved continuously for ∼ 20–30 kyr. Between 9 and 6 cal kyr BP the rate of sea-level rise exceeded the Namakdan diapir uplift rate by the factor of 3. As a consequence upward incision of cave streams (paragenetic trend) occurred, and blind valleys near the seashore were filled with gravels. Cave passages now accessible on the Namakdan and Hormoz diapirs started to form 3–6 cal kyr BP when sea level stabilized and downward stream incision began. Older cave levels are still preserved but are filled with sediments and salt precipitates. A comparison of the Namakdan diapir evolution with data from the Hormoz and Larak diapirs shows that the evolution of diapir morphology is strongly affected by the differences in uplift rates and geological settings. The general scheme of the evolution of the Namakdan diapir is believed to be partly applicable to many other diapirs in coastal settings.

Young uplift in the non-glaciated parts of the Eastern Alps

We report the first incision rates derived from burial ages of cave sediments from the Mur river catchment at the eastern margin of the Eastern Alps. At the transition zone between the Alpine orogen and the Pannonian basin, this river passes through the Paleozoic of Graz — a region of karstifiable rocks called the Central Styrian Karst. This river dissects the study area in a north–south direction and has left behind an abundance of caves. These caves can be grouped into several distinct levels according to their elevation above the present fluvial base level. Age estimates of abandoned cave levels are constrained by dating fluvial sediments washed into caves during the waning stages of speleogenesis with the terrestrial cosmogenic nuclide method. These ages and the elevations of the cave levels relative to the current valley floor are used to infer a very complex history of 4millionyears of water table position, influenced by the entrenchment and aggradation of the Mur river. We observe rather low rates of bedrock incision over the last 4Ma (in the order of 0.1mm/y) with an e-folding decrease in this trend to lower rates at younger times. We relate this incision history to a tectonic setting where an increase of drainage area of the Mur river due to stream piracy in Late Miocene to Pliocene times is linked to surface uplift. The later decrease in valley lowering rates is attributed to the rise of the base level related to aggradation of sediments within the valley. Sediment transport through the valley from the upstream section of the Mur river limited the erosional potential of the river to a transport limited state at the later stages of the incision history.

The role of hydrogeological base level in the formation of sub-horizontal caves horizons, example from the Dead Sea Basin, Israel

This paper deals with the hydrogeological relationship between base levels of saline lakes and the formation of sub-horizontal caves. The mechanism presented here suggests that many horizontal cave levels in carbonate sequences are created adjacent to the saline lakes shorelines because of the converging of the groundwater flow above the fresh–saline water interface. The main factors that control enhanced carbonate dissolution and cave formation are high groundwater flow velocities in the shallow phreatic zone during a relative long steady state of the water table. High groundwater flow velocities are evident close to the Dead Sea due to the convergent fast flows above the shallow interface adjacent to the shoreline. The same could prevail in the case of previous paleo-lakes that existed in the basin. The synergetic combination of the above preconditions for enhanced cave formation seems to be responsible for the formation of elevation-controlled alignment of paleo-near shore cave levels in the central and southern (Dead Sea) portion of the study area. These are found on the western fault escarpment and basin margin in different stratigraphic horizons of carbonate lithology. Many of the cave levels can be linked to late Quaternary–Holocene lake levels obtained from dated lake sediments within the basin. The most common cave’s elevation was found to be around 200 m below sea level which was the elevation of the Lisan Lake during part of its history. On the other hand, the Hula Basin in the northern part of the Dead Sea Basin was not occupied by saline water bodies since its formation as a base level, and thus the above preconditions for enhanced cave formation did not prevail. Indeed, this is evident by the lack of horizontal cave levels on its western carbonate margins unlike the situation in the south.

The effect of river dynamics induced by the Messinian Salinity Crisis on karst landscape and caves: Example of the Lower Ardèche river (mid Rhône valley)

The karstic canyon of Lower Ardèche is located in the Middle Rhône valley, which is directly tributary to the Mediterranean Sea. The Rhône River is emblematic of the Messinian Salinity Crisis (MSC) impact on landscape morphology. Along the edge of the Saint-Remèze Plateau, the Rhône valley displays four benchmark levels generated by the MSC: the Pre-evaporitic abandonment surface (1), the Messinian erosional surface (2), the Marine/non-marine surface of the Pliocene ria (3) and the Pliocene abandonment surface (4). The study of these benchmark levels allows us to reconstruct the evolution of the regional base level over the last 6 Ma. We obtain a curve for base-level evolution that provides a geodynamic reference, which is used to investigate the morphogenesis of the Saint-Remèze karstic plateau. The Ardèche River downcuts the Saint-Remèze Plateau in a deep canyon, from Vallon-Pont-d'Arc to the West, to its confluence with the Rhône to the East. Several abandoned valleys are present along the western edge of the Saint-Remèze Plateau at the inlet of the Ardèche canyon. In these abandoned valleys, the fluvial deposits are related to several periods, from the Pliocene onwards. They provide important insights into the fluvial dynamics: a 160 m-thick aggradation sequence infilled the Ardèche canyon during the Pliocene. This aggrading river caused the first lateral shifting, as an aggradation epigenesis. This first infilling shows that the Ardèche canyon already existed before the Pliocene. Secondly, it has been demonstrated that the Ardèche Canyon is downcut into the Pre-evaporitic surface of the Saint-Remèze Plateau, dated to 5.45 Ma [Martini, J., 2005. Etude des paléokarsts des environs de Saint-Remèze (Ardèche, France): mise en évidence d'une rivière souterraine fossilisée durant la crise de salinité messinienne. Karstologia 45–46, 1–18]. Consequently, the canyon downcutting is entirely due to the MSC, and occurred during a time span of only 100 000 years. Based on these observations, it is possible to elucidate the curve of the regional base-level evolution. Hence, we are able to propose a new interpretation of the geomorphological evolution of the Saint-Remèze karstic plateau and its cave levels for the last 6 Ma. The cave levels consist in underground short-cuts of the surface meanders. They mainly developed during the Pliocene aggradation cycle. The Chauvet Cave, famous for its Palaeolithic paintings, corresponds to one of these underground short-cuts. The aggradation period ends at the end of the Pliocene with long high-level riverbed stability. It favours the development of large low gradient surfaces as pediments. The complete Messinian–Pliocene eustatic cycle is responsible for the downcutting of the Ardèche canyon and its infilling during the Pliocene. Consequently, karst developed according to the base-level oscillations, as low gradient surfaces and as cave levels. For the study of the peri-Mediterranean caves and karst areas, we propose to apply the Lower Ardèche valley evolution model, based on the base-level oscillations during and after the MSC.

Constraints on alpine speleogenesis from cave morphology — A case study from the eastern Totes Gebirge (Northern Calcareous Alps, Austria)

The Totes Gebirge is the largest karst massif in the Northern Calcareous Alps (NCA). This paper focuses on the eastern part, where two major multiphase alpine cave systems (Burgunderschacht Cave System and DÖF–Sonnenleiter Cave System) are described with respect to morphology, hydrology, and sediments. The caves consist of Upper Miocene galleries of (epi)phreatic genesis and younger vadose canyon-shaft systems. Morphometrical analyses were used to determine the relevance of (1) cave levels (horizontal accumulations of galleries), (2) slightly inclined palaeo water tables of speleogenetic phases, (3) initial fissures, and (4) inception horizons on the development of the cave systems. (Epi)phreatic cave conduits developed preferentially along vertical faults and along only a restricted number of bedding planes, which conforms to the inception horizon hypothesis. For at least one of the systems, a development under epiphreatic conditions is certain and a hydrological behaviour in the “filling overflow manner” is likely. Observations in further major cave systems in the Totes Gebirge identify palaeo water tables of speleogenetic phases that show inclinations of 1.5° ± 1°. Analyses of cave levels reveal distinct peaks for each cave but it is hardly possible to correlate these elevation levels between caves of different parts of the karst massif. Therefore, we conclude that cave levels (strictly horizontal) indicate speleogenetic phases or palaeo water tables respectively, but they cannot be correlated with palaeo base levels or on regional scale. An exact correlation between cave development and palaeo base levels at the surface is only possible with inclined palaeo water tables of speleogenetic phases. For the Totes Gebirge, the inclination directions of the speleogenetic phases imply that palaeo drainage was radial and recharge was autogenic, which is in contrast to observations from other plateaus in the NCA. Differences in fracture properties seem to be the reason for the development of divergent types, according to the Four State Model. A simplified model for cave genesis and surface development in this area since the Upper Miocene is presented.

Quaternary cave levels in peninsular Florida

The hypothesis that caves in the Florida Peninsula are tied to Quaternary sea levels was proposed by hydrogeologists, without data, some 40 years ago. The hypothesis is a version of glacial control of cave levels, which is the logical combination of the water-table theory of speleogenesis and the concept that base level positions the water table. At the USA type example of glacial control of cave levels—Mammoth Cave in the Paleozoic rocks of Kentucky—the intermediary is base level determined by rivers. By hypothesis, the intermediary for Florida is glacioeustatic sea level. This paper presents elevation data that supports this hypothesis. Recent cave surveys in the air-filled caves and spot elevations from archived maps reveal prominent levels of passages centered at 5, 12, 21, and 30 m above sea level over broad areas. They do not follow the large-scale structure of the Floridan aquifer. Instead, they align with nearby, coastal marine terraces identified as modal peaks on frequency plots from various topographic data bases. Levels matching with the three highest terraces—Wicomico, Penholoway, and Talbott—are particularly clear. Lower levels, if they accord with sea-level stands, are likely composites. Data from cavities encountered in drilled wells (e.g., bit drops) and spot elevations from archived underwater cave maps demonstrate passage levels at depths of 15, 30, 70, and 90–120 m below the modern water table. The depths below water table are similar to the depths below sea level of distant submerged terraces and paleoshoreline features identified using multibeam bathymetric data in the Gulf of Mexico. The cave, bit-drop, and terrace data are all consistent with the concept that Quaternary sea level is the fundamental control on the cave-scale porosity within the Floridan aquifer. This conclusion does not rule out the possibility that lithologically favored positions, paleokarst features and confining units, and mixing zones are also involved in the location of caves levels in this near-coastal environment.

Formation and dating of a salt pillar in Mount Sedom diapir, Israel

The formation of a 20-m-high salt pillar in Mount Sedom, Dead Sea area, was analyzed and dated, and these results were complemented by measurement of present uplift rate because the pillar is a part of the actively rising Sedom diapir. Contrary to earlier assumptions, which stated that the salt pillar was formed by direct rainfall, the observed solutional notches and morphology of the neighboring chasm indicate that the salt pillar is due to a karstic cave that collapsed. The uppermost part of the cave still carried an underground ephemeral stream ~4000 yr ago, as indicated by six 14C dates of wood washed into the highest cave level. The sudden collapse that left the isolated salt pillar was probably triggered by a catastrophic earthquake. The measured uplift rate, 9.3 ± 3.5 mm/yr, shows that when the pillar formed, it was much closer to the base of Mount Sedom.

Comparison of U–Th, paleomagnetism, and cosmogenic burial methods for dating caves: Implications for landscape evolution studies

Caves are useful in landscape evolution studies because they often mark the level of previous water tables and, when dated, yield incision rates. Dating caves is problematic, however, because their ages are only constrained by the oldest deposits contained within, which may be far younger than the cave itself. We dated cave deposits in the Sierra Nevada using U–Th dating of speleothems, paleomagnetic dating of fine sediment, and cosmogenic 26Al/ 10Be burial dating of coarse sediment. The sampled caves formed sequentially as the water table lowered, providing an important stratigraphic test for the dating methods. Large discrepancies between deposit ages from similar cave levels demonstrate that, even when accurately determined, deposit ages can seriously underestimate the timing of cave development. Drip-type speleothems are most prone to this minimum age bias because they can accumulate long after caves form, and because the U–Th method is limited to ∼400 ka. Paleomagnetic dating requires correlation with the global reversal chronology, and is hindered by a lack of continuous stratigraphy. The fine sediment analyzed for paleomagnetism is also highly susceptible to remobilization and deposition in cave passages well above base level. Cosmogenic 26Al/ 10Be dates bedload material deposited when caves were at or very near river level, and can date material as old as ∼5 Ma. In the Sierra Nevada, speleothem U–Th ages and sediment burial ages from the same cave levels differ by as much as an order of magnitude. These results suggest speleothem ages alone may significantly underestimate cave ages and thereby overestimate rates of landscape evolution. Cosmogenic burial dating of coarse clastic sediment appears to be the most reliable method for dating cave development in mountainous regions.

The effect of the Messinian Deep Stage on karst development around the Mediterranean Sea. Examples from Southern France

It is difficult to explain the position and behaviour of the main karst springs of southern France without calling on a drop in the water table below those encountered at the lowest levels of Pleistocene glacio-eustatic fluctuations. The principal karst features around the Mediterranean are probably inherited from the Messinian period (“Salinity crisis”) when sea level dropped dramatically due to the closing of the Straight of Gibraltar and desiccation of the Mediterranean Sea. Important deep karst systems were formed because the regional ground water dropped and the main valleys were entrenched as canyons. Sea level rise during the Pliocene caused sedimentation in the Messinian canyons and water, under a low hydraulic head, entered the upper cave levels. The powerful submarine spring of Port-Miou is located south of Marseille in a drowned canyon of the Calanques massif. The main water flow comes from a vertical shaft that extends to a depth of more than 147 m bsl. The close shelf margin comprises a submarine karst plateau cut by a deep canyon whose bottom reaches 1,000 m bsl. The canyon ends upstream in a pocket valley without relation to any important continental valley. This canyon was probably excavated by the underground paleoriver of Port-Miou during the Messinian Salinity Crisis. Currently, seawater mixes with karst water at depth. The crisis also affected inland karst aquifers. The famous spring of Fontaine de Vaucluse was explored by a ROV (remote observation vehicle) to a depth of 308 m, 224 m below current sea level. Flutes observed on the wall of the shaft indicate the spring was formerly an air-filled shaft connected to a deep underground river flowing towards a deep valley. Outcroppings and seismic data confirm the presence of deep paleo-valleys filled with Pliocene sediments in the current Rhône and Durance valleys. In the Ardèche, several vauclusian springs may also be related to the Messinian Rhône canyon, located at about 200 m below present sea level. A Pliocene base level rise resulted in horizontal dry cave levels. In the hinterland of Gulf of Lion, the Cévennes karst margin was drained toward the hydrologic window opened by the Messinian erosional surface on the continental shelf.

Human Skull from the Taza Locality, Jijel, Algeria

Archaeological excavations were carried out in 1990 in prehistorically inhabited caves sites in the Taza locality along the eastern Algerian coast. Recovered materials included stone and bone artifacts, faunal remains and a single human skull (Taza 1). A radiocarbon date for the upper cave level from which the skull was found was 16,100 B.P. While the skull, which is likely female, is very small overall, its shape compared closely with other North African cranial series. The obtained date and archaeological materials are characteristic of the Iberomaurusian industry of the Late Paleolithic period of North Africa.

Interview with a Neanderthal: an Experimental Approach for Reconstructing Scraper Production Rules, and their Implications for Imposed Form in Middle Palaeolithic Tools

This article investigates the degree and nature of ‘imposed form’ in Middle Palaeolithic scrapers, the most common category of stone tool produced by Neanderthals. Novice flintknappers unfamiliar with Middle Palaeolithic tool forms were found to consistently employ two rules in manufacturing scrapers: the striking platform and any adjacent blunt edges were left intact to facilitate prehension, and the longest edge with the most acute spine-plane angle was retouched. Scrapers from three major Middle Palaeolithic sites adhered to these rules in over 90 per cent of cases, but significant divergence from these rules was found in a sample from Skhul cave (Israel) level B1, associated with early anatomically modern Homo sapiens. It is concluded that Middle Palaeolithic scraper manufacture was structured by the need to create a suitable working edge, and to locate that edge to maximize ease and comfort during manufacture and use. The overall shape of the resulting tools was thus not an expression of ‘imposed form’ in the conventional sense. The discovery of violations of these rules in the Skhul B1 collection provides evidence of increased use of imposed form, as well as potentially significant behavioural differences between early anatomically modern Homo sapiens and contemporary Neanderthals.

Patterns of time and space utilisation in coelacanths ( Latimeria chalumnae ), determined by ultrasonic telemetry

Acoustic telemetry was used to examine patterns of activity and space utilisation of coelacanths, nocturnal predators which spend the day in submarine caves. Nine coelacanths (Latimeria chalumnae) were tracked, each for a period of 1 to 16 nights at Grande Comore, West Indian Ocean. Activities lasted on average 9 h, usually starting shortly after sunset and ending before sunrise. Vertically, coelacanths moved up and down at and below cave level by following the bottom contour, mainly between 180 and 400 m depth. The deepest record was 698 m, the shallowest 133 m. Most time was spent between 200 and 300 m depth. Large individuals performed deep excursions to depths below 400 m, usually once per night. The fish spent most time in water temperatures of 15 to 19 °C; they rarely ventured into waters warmer than 22 °C measured at depths shallower than 160 m depth. Horizontally, coelacanths stayed in narrow areas ranging from <1 to 10 km of coastline. Coelacanths are extremely slow drift-hunters with an estimated average swimming speed of 3.2 m min−1, often travelling not more than 3 km per night. They probably take advantage of local upwelling and downwelling and slow currents occurring parallel to the steep slopes. This study shows that coelacanths are inhabitants of the subphotic zone, where they are active mainly below the depth of their daytime refuges.

Apparent increasing rates of stream incision in the eastern United States during the late Cenozoic

Stream incision rates were obtained from 16 studies of terraces or stream-associated cave levels in the eastern United States. A log-log regression of age against height above modern river level (ARL) shows that age increases approximately as the square of height ARL. This relation may indicate an increasing rate of stream incision through time. Alternatively, the relation may simply reflect an inherent effect of measured time interval on process rate, as described by Gardner et al., who found that data from hundreds of studies showed a tendency for geologic process rates to decrease for increasing measurement intervals. A regression equation for landscape denudation rates showed that the thickness removed increased as the 0.82 power of the time interval over which the denudation was measured. Gardner et al. suggested that this bias could be removed by the use of statistically derived scaling functions. However, a similar regression equation for the data in this study shows a slope of 0.38, representing a much more rapid decrease in rate with increasing measurement interval than found by Gardner et al. Even after applying the scaling function calculated by Gardner et al., my data show a 19 fold decrease in incision rate for a 103 increase in the measured time interval. This result suggests that the observed decrease in stream incision rates with greater time spans may be at least partly real.

Interprétation morphométrique et spéléogenèse : exemples de réseaux karstiques de Basse-Provence (directions de galeries, modèle et maillage structural)

Morphometry interpretation and speleogenesis. Examples of caves in the Provence area , France (gallery orientations, patterns and structural grid). Successive tectonic phases on limestone massifs are at the origin of a fracturation grid with several pattern dimensions, and linear or organized, drain directions. Mechanical reactivations are observed from Oligocene until Plio-Quaternary on a former «pyrénéo-provençal» structure (Eocene). Statistical analysis of gallery and fracture directions, cave levels and descent stages (overdeepening) show several erosional stages occurring after the formation of the Antevindobonian erosional surface. The active speleogenesis during Oligocene and Miocene was controlled by tectonics in connection with European rifting and mediterranean opening. In Messinian a short and significant lowering of mediterranean base level (and water table) made drastic erosion and created vertical pits. The horizontal cave level dug during the stabilization phase of Pliocene, now perched over underground rivers, shows a new overdeepening because of glacio-eustatic Quaternary oscillations. Compressive or distensive mechanical reactivations (Upper Miocene, Pliocene, Quaternary ) modified the drainage and consequently the cave organization : self-piracy, confluence and diffluence. In the endokarst, the drainage inversion can be detected in late Upper continental Miocene and early Messinian (6,5 My), in correlation with the tilting and extension of the continental margin. Five caves in Provence are studied : Sabre, Petit Saint-Cassien, Rampins, Planesselve river, and Tête du Cade networks.

Uplift rate relative to base-levels of a salt diapir (Dead Sea Basin, Israel) as indicated by cave levels

Abstract Rapid downcutting rates in the extremely soluble salt of the Sedom diapir, Dead Sea basin, Israel, allow cave channels to become rapidly graded with respect to base level. Diapir uplift leaves the older passages high and dry above present base level. Dating these passages by 14 C allows us to estimate diapir uplift rates, taking into account previous Dead Sea levels. Maximum mean Holocene uplift rates are 6–7 mm a −1 along the eastern fault of Mount Sedom.

Cave levels and cave development in the mitchell plain following base‐level lowering

AbstractMultiple levels evolved in Buddha–Christian's Cave and in Donaldson's–Bronson's–Twin Cave in a subtly different manner to that normally associated with the development of multilevel caves adjacent to entrenched river valleys. It is often assumed that lower cave levels are generated by successive phases of valley entrenchment; however, multiple levels may also be induced by progressive adjustments in groundwater flow paths. Such adjustments occur as the effects of a change in base level propagate up‐basin. In the Mitchell Plain much of the late Pleistocene drop in the elevation of the principal drainage (the East Fork of the White River) was accommodated by entrenchment along the lower reaches of tributary valleys. Caves initially developed in the mid‐sections of tributary basins at relatively shallow depths. In the vicinity of the cave exit, the piezometric surface gradually steepened and was eventually lowered through a combination of valley headwall retreat and the incremental concentration of flow through master conduits. Upper‐level passages were abandoned once the original high‐level flow paths were replaced by lower‐level routes.

Unconformities, Paleokarst Facies, and Porosity Evolution: ABSTRACT

The study of unconformities and paleokarsts from the perspective of modern facies analysis and modeling offers potential advantages in terms of organizing and guiding observations, comparisons, interpretations, predictions, and hydrodynamic considerations. Karsts that developed at major unconformities may result in karst facies and profiles different in many respects from those of meteoric diagenesis in Quaternary carbonates in tropical areas (e.g., the Caribbean). Many paleokarsts developed on mud-supported carbonates after mineralogical stabilization, deep burial, and tectonic deformation, but without the diffuse recharge and flow characteristics of the Caribbean model or the influence of a coastal marine mixing zone. The general concepts of water table and vadose and phreatic regimes need careful review when applied to heterogeneous permeability networks. Karst facies and profiles are controlled by (1) previous permeability networks of the affected formation, (2) balance and interaction of climatic, biologic, and hydrologic environments that enhance or reduce these permeability networks, and (3) timing, rate, and succession of environments, and stages of evolution. Karst facies, facies associations, and their profile arrangements generally vary, and may be complicated by relict and rejuvenated features common in evolved karst profiles. In detail, karst facies are defined in terms of (1) corrosion-erosion morphologies, (2) diagenetic overprints, (3) karst sediments and cements (speleothems), and (4) biologic associations. A common, mature, authigenic karst profile consists of the following zones. (1) Soil, infiltration zone--down to the limit of root penetration. (2) Percolation zone--with vertical passages and abundant sedimentation, collapse, and cementation, commonly containing relict features (cave levels) from deeper horizons or local saturation zones. (3) Oscillation zone--characterized by periodic water saturation and, in terms of lithofacies, commonly indistinguishable from the permanent lenticular zone (shallow phreatic); predominantly horizontal passages with bedding-plane control and erosional features are the key characteristics of this zone; cave sediments show evidence for reducing depositional environments; many well logs show a characteristic kick in the gamma ray (B marker), together w th a decrease in the sonic activity. And (4) deep phreatic zone--characterized by incipient, slow corrosion and/or cementation and grading into the unaffected formation. In most places, a rock formation is first exposed to the deep phreatic zone and evolves through the shallow phreatic into the vadose as a result of the dismantling of the upper part of the profile. In this way, the classic concepts of youth, maturity, and senility can apply to parts of the karst profile or to the entire profile, and can provide a basis for comparing other profiles of the same karst system. Base level changes are commonly sharp and produce repeated horizontal cave levels that are abandoned in the vadose part of the profile. In many paleokarsts, those relict cave levels have been confused with repeated surfaces of subaerial exposure. Correlating different karst profiles and the structural-lithologic patterns of the affected formation offer the possibility of reconstructing the evolution of drainage patterns during major unconformities. This karst facies modeling can also provide a basic tool for reservoir evaluation in exploration and production. End_of_Article - Last_Page 1440------------

Dating of cave sediments at Wee Jasper, New South Wales, by magnetostratigraphy

Previously Punchbowl, Signature and Dogleg Caves low down in the Goodradigbee valley at Wee Jasper, NSW, could only be inferred to be younger than Early Miocene basalts on the plateau to the west. Five main quasi‐horizontal cave levels, with discrete bodies of fluvial sediment at more frequent intervals, invited application of magnetostratigraphy to this sequence of passages, which are successively younger downwards, in the hope of more precise dating. Thirteen sites at 10 altitudes over a range of 31 m were sampled at 2–8 points each. The lower third of the system yielded normal polarity and so formed since 0.73 Ma. Treating the palaeomagnetic data conservatively, the upper two thirds, yielding dominantly reversed polarities, can be regarded as forming between the Brunhes‐Matuyama boundary and the Jaramillo. However, this implies a drastic change in rate of lowering of local karst base level and valley incision for which there is no morphological support. Assuming a linear rate of vertical cave developme...

Cave Levels of Trenton-Black River in South-Central Michigan: ABSTRACT

Four generalized cave levels of the Trenton-Black River in south-central Michigan are most notable because of lost circulation zones in productive field areas. The levels are herein referred to as uppermost, upper middle, lower middle, and lowermost. The uppermost cave level extends about 250 ft (76 m) into the Trenton. It is best developed in the widest, most productive areas of Albion-Scipio, where the drill bit dropped as much as 62 ft (19 m). About 59 productive wells in Albion-Scipio lost circulation at this level. The upper middle level includes the lower, slightly argillaceous Trenton, and the uppermost River formation. This level is developed to some extent in all fields, and is a common zone of solution-collapse brecciation. Because this level is collapsed, lost circulation is less common. The lower middle level below the Black River shale is not penetrated by many wells in Albion-Scipio. Where penetrated, it is developed in all fields, and is the main producer in most smaller fields. About 26 wells in Albion-Scipio lost circulation at this level, with the drill bit dropping as much as 80 ft (24 m). The lowermost cave level extends into the Glenwood Shale. It is the most widely developed level, but is intersected by few productive holes. Only seven wells lost circulation at this level in Albion-Scipio, but the drill bit has dropped as much as 8 ft (2.4 m) in the Glenwood. This cave level effectively drained some oil from reservoirs where the oil-water contact intersects the Glenwood. End_of_Article - Last_Page 1918------------