Community news

Speleology in Kazakhstan

Shakalov on 04 Jul, 2018
Hello everyone!   I pleased to invite you to the official site of Central Asian Karstic-Speleological commission ("Kaspeko")   There, we regularly publish reports about our expeditions, articles and reports on speleotopics, lecture course for instructors, photos etc. ...

New publications on hypogene speleogenesis

Klimchouk on 26 Mar, 2012
Dear Colleagues, This is to draw your attention to several recent publications added to KarstBase, relevant to hypogenic karst/speleogenesis: Corrosion of limestone tablets in sulfidic ground-water: measurements and speleogenetic implications Galdenzi,

The deepest terrestrial animal

Klimchouk on 23 Feb, 2012
A recent publication of Spanish researchers describes the biology of Krubera Cave, including the deepest terrestrial animal ever found: Jordana, Rafael; Baquero, Enrique; Reboleira, Sofía and Sendra, Alberto. ...

Caves - landscapes without light

akop on 05 Feb, 2012
Exhibition dedicated to caves is taking place in the Vienna Natural History Museum   The exhibition at the Natural History Museum presents the surprising variety of caves and cave formations such as stalactites and various crystals. ...

Did you know?

That gypsum flower is see cave flower.?

Checkout all 2699 terms in the KarstBase Glossary of Karst and Cave Terms

What is Karstbase?



Browse Speleogenesis Issues:

KarstBase a bibliography database in karst and cave science.

Featured articles from Cave & Karst Science Journals
Chemistry and Karst, White, William B.
See all featured articles
Featured articles from other Geoscience Journals
Karst environment, Culver D.C.
Mushroom Speleothems: Stromatolites That Formed in the Absence of Phototrophs, Bontognali, Tomaso R.R.; D’Angeli Ilenia M.; Tisato, Nicola; Vasconcelos, Crisogono; Bernasconi, Stefano M.; Gonzales, Esteban R. G.; De Waele, Jo
Calculating flux to predict future cave radon concentrations, Rowberry, Matt; Marti, Xavi; Frontera, Carlos; Van De Wiel, Marco; Briestensky, Milos
Microbial mediation of complex subterranean mineral structures, Tirato, Nicola; Torriano, Stefano F.F;, Monteux, Sylvain; Sauro, Francesco; De Waele, Jo; Lavagna, Maria Luisa; D’Angeli, Ilenia Maria; Chailloux, Daniel; Renda, Michel; Eglinton, Timothy I.; Bontognali, Tomaso Renzo Rezio
Evidence of a plate-wide tectonic pressure pulse provided by extensometric monitoring in the Balkan Mountains (Bulgaria), Briestensky, Milos; Rowberry, Matt; Stemberk, Josef; Stefanov, Petar; Vozar, Jozef; Sebela, Stanka; Petro, Lubomir; Bella, Pavel; Gaal, Ludovit; Ormukov, Cholponbek;
See all featured articles from other geoscience journals

Search in KarstBase

Your search for landscape evolution (Keyword) returned 50 results for the whole karstbase:
Showing 31 to 45 of 50
Modle dvolution de paysages, application aux karsts en cockpit de Jamaque, 2007, Fleurant Cyril , Tucker Gregory, Viles Heather
LANDSCAPE EVOLUTION MODEL, EXAMPLE OF COCKPIT KARST TERRAINS, JAMAICA. A model of cockpit karst landscape evolution is presented. After explaining implementation of dissolution processes of limestone in the landscape evolution model CHILD, we develop a model of limestone denudation based on epikarst theory processes. The model takes into account an anisotropic dissolution in space and time according to what is observed in reality or described by scenarios of cockpit karst landscape evolution. This model requires a fractures network to take into account subsurface flow. Then, dissolution and thus fractures widening are computed and show a positive feedback between dissolution and flow. The relation between subcutaneous dissolution of fractures and denudation of the topography is introduced by means of an empirical equation associated with epikarst processes: the denudation is taken to be proportional to the dissolution in the subcutaneous zone. Simulated cockpit karst terrains are compared with real landscapes by means of morphometric criteria. Results of the model are very close to reality which hence confirms the importance of anisotropic dissolution processes and above all could be a numerical validation of the epikarst processes to describe cockpit karst genesis.

Cave Geology, 2007, Palmer A. N.
Cave Geology is the definitive book on the subject by an internationally recognized authority. It can be easily understood by non-scientists but also covers a wide range of topics in enough detail to be used by advanced researchers. Illustrated with more than 500 black-and-white photographs and 250 diagrams and maps, this book is dedicated to anyone with an interest in caves and their origin. Topics include: CONTENTS Preface 1 Speleology the science of caves Cave types Cave exploring Nationwide speleological organizations Searching for caves Cave mapping Preparation of a cave map Cave science Underground photography Show caves Cave preservation and stewardship 2 Cave country Geologic time Landscape development Surface karst features Paleoleokarst Pseudokarst The scale of karst features Distribution of karst and caves The longest and deepest known caves 3 Cavernous rocks Rock types Soils and sediments Stratigraphy Highly soluble rocks Rock structure Rock and mineral analysis A brief guide to rock identification 4 Underground water in karst Types of underground water Vadose flow patterns Phreatic flow patterns Aquifers Nature of the karst water table The freshwater-seawater interface Groundwater hydraulics Flow measurements Use of flow equations in cave interpretation Measuring the flow of springs and streams Groundwater tracing Interpreting groundwater character from tracer tests and flood pulses Quantitative dye tracing 5 Chemistry of karst water Simple dissolution Dissoltion of limestone and dolomite How much rock has dissolved? pH Undersaturation and supersaturation Epigenic and hypogenic acids Chemical interactions Dissolution rates Dissolution of poorly soluble rocks Microbial effects on chemistry Isotopes and their use Analysis of spring chemistry A chemical cave tour Chemical field studies 6 Characteristics of solution caves Cave entrances Passage types Passage terminations Cave rooms Cave levels Cave patterns Minor solution features in caves Interpreting flow from scallops Cave sediments Bedrock collapse Cave biology 7 Speleogenesis: the origin of caves Basic concepts Development of ideas about cave origin Comprehensive views of cave origin Rates of cave enlargement Insight from computer modeling Life cycle of a solution cave 8 Control of cave patterns by groundwater recharge Sinkhole recharge: branchwork caves The problem of maze caves Floodwater caves Caves formed by diffuse flow Hypogenic caves Polygenetic caves Influence of climate 9 Influence of geology on cave patterns Distribution of soluble rocks Influence of rock type Influence of geologic structure Relation of caves to landscape evolution A guide to cave patterns 10 Cave minerals Origin and growth of cave minerals Origin of common cave minerals Speleothem types Speleothem growth rates Speleothem decay 11 Caves in volcanic rocks Volcanic processes and landscapes Types of lava caves Origin and character of lava-tube caves Speleogens and speleothems in lava caves Time scale of lava caves 12 Cave meteorology and internal weathering Composition of cave air Cave temperatures Air movement Evaporation and condensation Weathering in the cave atmosphere Chemical zones in air-filled caves 13 Caves and time Relative and numerical ages Determining cave ages Studies of past climates Caves through the ages 14 Geologic studies of caves Field mapping Calibrating survey instruments Geologic interpretions Testing interpretations for validity Detailed analysis of a cave Further goals 15 Application of cave geology to other geosciences The problem of sampling bias Water supply Engineering applications Land management Interpretation of geologic processes Petroleum geology Mining Scientific frontiers The limits of discovery Glossary References Index Conversion between U.S. and metric units

Evolution and age relations of karst landscapes, 2007, White, W. B.

Any karst landscape is a work in progress. The observed evolution of the landscape is dictated by competing rate processes of surface denudation, stream downcutting, cave development, and tectonic uplift. quantitative data on these processes, applied to two physiographic provinces of the Appalachian Mountains of eastern United States gives ages and time scales that are in agreement with previous geomorphic interpretation. The results are anchored, very loosely, by the few dates that have been established for cave sediments. Unfortunately, the measured rates vary over an order of magnitude as a result of local circumstances making regional interpretation a rough approximation at best.

Cave and Karst evolution in the Alps and their relation to paleoclimate and paleotopography, 2007, Audra P. , Bini A. , Gabrovš, Ek F. , Hä, Uselmann P. , Hoblé, A F. , Jeannin P. Y. , Kunaver J. , Monbaron M. , Š, Uš, Terš, Ič, F. , Tognini P. , Trimmel H. , Wildberger A.

Progress in the understanding of cave genesis processes, as well as the intensive research carried out in the Alps during the last decades, permit to summarize the latest knowledge about Alpine caves. The phreatic parts of cave systems develop close to the karst water table, which depends on the spring position, which in turn is generally related to the valley bottom. Thus, caves are directly linked with the geomorphic evolution of the surface and reflect valley deepening. The sediments deposited in the caves help to reconstruct the morphologic succession and the paleoclimatic evolution. Moreover, they are the only means to date the caves and thus the landscape evolution. Caves appear as soon as there is an emersion of limestone from the sea and a water table gradient. Mesozoic and early tertiary paleokarsts within the alpine range prove of these ancient emersions. Hydrothermal karst seems to be more widespread than previously presumed. This is mostly due to the fact that usually, hydrothermal caves are later reused (and reshaped) by meteoric waters. Rock-ghost weathering is described as a new cave genesis agent. On the contrary, glaciers hinder cave genesis processes and fill caves. They mainly influence cave genesis indirectly by valley deepening and abrasion of the caprock. All present datings suggest that many alpine caves (excluding paleokarst) are of Pliocene or even Miocene age. Progress in dating methods (mainly the recent evolution with cosmogenic nuclides) should permit, in the near future, to date not only Pleistocene, but also Pliocene cave sediments absolutely.

Clastic sediments in caves imperfect recorders of processes in karst, 2007, Sasowsky, I. D.

Clastic sediments have played an important role in deciphering geologic history and processes since the inception of the discipline. Early studies of caves applied stratigraphic principles to karst deposits. The majority of cave deposits are breakdown and alluvium. The alluvial materials have been successfully investigated to determine ages of caves, landscape evolution, paleoenvironmental conditions, and paleobiota. Rapid stage changes and the possibility of pipe-full flow make cave deposits different than surface deposits. This and other factors present difficulties with interpreting the cave record, but extended preservation is afforded by the “roofing” of deposits. Dating by magnetism or isotopes has been successful in many locations. Caves can be expected to persist for 10 Ma in a single erosive cycle; most cave sediments should be no older than this.

Cyclic sedimentation in Brazilian caves: Mechanisms and palaeoenvironmental significance, 2009, Auler Augusto S. , Smart Peter L, Wang Xianfeng, Piló, Luí, S B. , Edwards Lawrence, Cheng Hai

Caves associated with doline slopes in the tectonically stable area of eastern Brazil display remarkable sequences of clastic sediment intercalated with calcite layers. Sediment erosion has also occurred allowing access to formerly sediment-filled passages. The palaeoenvironmental meaning and chronology of these three processes (i.e. clastic sediment input, clastic sediment erosion, and speleothem precipitation) were studied in both semi-arid Campo Formoso and sub-humid Lagoa Santa areas through 230Th dating and stratigraphical analyses. The dry climate of the Campo Formoso area prevents speleothem deposition at present, but soil erosion results in valley aggradation and cave infilling. Growth periods of speleothems and travertines in this area have allowed the recognition of recurrent past phases of increased humidity correlated with wet conditions recorded in southeastern Brazil speleothem calcite. At the Lagoa Santa area there is limited speleothem precipitation and sediment input at present. However, sediment entrainment is actively exhuming speleothems and exposing cave passages. Sediment erosion inside caves in the area is interpreted as being due to intermediate climatic conditions, not wet enough to favour speleothem deposition and not too dry to allow doline slope erosion and sediment transport into caves.
Due to the low rates of denudation and isostatic rebound inherent to tectonically stable areas, cave passages will remain within the range of sediment infill and erosion for a much longer time than in tectonically active areas spanning, in average, at least three full glacial–interglacial cycles. As uplift proceeds, cave passages will be decoupled from the doline bottom and no longer will be affected by erosion or infilling episodes. Sediment filled passages in many caves in the Lagoa Santa region are relict features that display ancient clastic and chemical precipitation. The three processes described above have occurred throughout the life history of the caves, resulting in complex sediment assemblages that can, however, show significant intra- and inter-site variations.

Young uplift in the non-glaciated parts of the Eastern Alps, 2010, Wagner T. , Fabel D. , Fiebig M. , Hä, Uselmann Ph. , Sahy D. , Xu S. , Stü, We K.

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 4 million years 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 4 Ma (in the order of 0.1 mm/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.

Correlations of cave levels, stream terraces and planation surfaces along the River MurTiming of landscape evolution along the eastern margin of the Alps, 2011, Wagner Thomas, Fritz Harald, Stü, We Kurt, Nestroy Othmar, Rodnight Helena, Hellstrom John, Benischke Ralf

The transition zone of the Eastern Alps to the Pannonian Basin provides one of the best sources of information on landscape evolution of the Eastern Alpine mountain range. The region was non-glaciated during the entire Pleistocene. Thus, direct influence of glacial carving as a landscape forming process can be excluded and relics of landforms are preserved that date back to at least the Late Neogene. In this study, we provide a correlation between various planation surfaces across the orogen-basin transition. In particular, we use stream terraces, planation surfaces and cave levels that cover a vertical spread of some 700 m. Our correlation is used to show that both sides of the transition zone uplifted together starting at least about 5 Ma ago. For our correlation we use recently published terrestrial cosmogenic nuclide (TCN) burial ages from cave sediments, new optically stimulated luminescence (OSL) ages of a stream terrace and U–Th ages from speleothems. Minimum age constraints of cave levels from burial ages of cave sediments covering the last ~ 4 Ma are used to place age constraints on surface features by parallelizing cave levels with planation surfaces. The OSL results for the top section of the type locality of the Helfbrunn terrace suggest an Early Würm development (80.5 ± 3.7 to 68.7 ± 4.0 ka). The terrace origin as a penultimate gravel deposit (in classical Alpine terminology Riss) is therefore questioned. U-series speleothem ages from caves nearby indicate formation during Marine Isotope Stages (MIS) 5c and 5a which are both interstadial warm periods. As OSL ages from the terrace also show a time of deposition during MIS 5a ending at the MIS 5/4 transition, this supports the idea of temperate climatic conditions at the time of deposition. In general, tectonic activity is interpreted to be the main driving force for the formation and evolution of these landforms, whilst climate change is suggested to be of minor importance. Obvious hiatuses in Miocene to Pleistocene sediments are related to ongoing erosion and re-excavation of an uplifting and rejuvenating landscape

Role of sediment in speleogenesis; sedimentation and paragenesis, 2011, Farrant Andrew R. , Smart Peter L.

Although the effects of sedimentation in caves have been recognised for many years, its role in speleogenesis is frequently overlooked. Influxes of sediment into a cave system fundamentally alter the way cave passages develop, either by alluviation in a vadose environment, forcing lateral corrosion and the development of notches, or by upwards dissolution in a phreatic environment through a process known as paragenesis. Sediment influxes affect the hydrological functioning of a karst aquifer by changing the way conduits behave and subsequently develop both in plan and long section.

Here we give an overview of the mechanisms of cave sedimentation and describe how the process of alluviation and paragenesis affect speleogenesis. A characteristic suite of meso- and micro-scale dissolutional features can be used to recognise paragenetic development, which is reviewed here. In a vadose environment these include alluvial notches, whilst in a phreatic environment, half tubes, anastomoses and pendants, bedrock fins and paragenetic dissolution ramps result. Using these to identify phases of sedimentation and paragenesis is crucial for reconstructing denudation chronologies from cave deposits. We suggest that sedimentation and paragenesis are most likely to occur in certain geomorphological situations, such as ice marginal and periglacial environments, beneath thick residual soils and where rivers can transport fluvial sediment into a cave, either via stream sinks or back-flooding.

Landscape evolution in southeast Wales: evidence from aquifer geometry and surface topography associated with the Ogof Draenen cave system, 2011, Simms Michael J, Farrant Andrew R

The evolution of the Ogof Draenen cave system, in south-east Wales, has been profoundly influenced by the geometry of the karst aquifer and its relationship with changes in the surface topography. Using data from within the cave combined with a model of the aquifer geometry based on outcrop data, we have estimated the location and elevation of putative sinks and risings for the system by extrapolating from surveyed conduits in the cave. These data have enabled us to assess the scale and pattern of scarp retreat and valley incision in the valleys of the Usk, Clydach and Lwyd, that together have influenced the development of the cave. From this we can construct a relative chronology for cave development and landscape evolution in the region. Our data show that scarp retreat rates along the west flank of the Usk valley have varied by more than an order of magnitude, which we interpret as the result of locally enhanced erosion in glacial cirques repeatedly occupied and enlarged during successive glacial cycles. This process would have played a key role in breaching the aquiclude, created by the eastward overstep of the Marros Group clastics onto the Cwmyniscoy Mudstone, and thereby allowed the development of major conduits draining further south. In the tributary valleys incision rates were substantially greater in the Clydach valley than in the Lwyd valley, which we attribute to glacial erosion predominating in the north-east-facing Clydach valley and fluvial erosion being dominant in the south-facing Lwyd valley. There is evidence from within Ogof Draenen for a series of southward-draining conduits graded to a succession of palaeoresurgences, each with a vertical separation of 4-5 m, in the upper reaches of the Lwyd valley. We interpret these conduits as an underground proxy for a fluvial terrace staircase and suggest a direct link with glacial-interglacial cycles of surface aggradation and incision in the Lwyd valley. Fluvial incision rates for broadly analogous.

Datierung fluviatiler Hhlensedimente mittels kosmogener Nuklide am Beispiel des Grazer Berglandes, 2011, Wagner, T.
The Central Styrian Karst north of Graz comprises a great number of caves of which many are of phreatic origin. Due to a clustering of caves at certain elevations above the current base level, the Mur River, these caves can be assigned to distinct levels. Caves cannot be older than the rock in which they formed, i.e. in the case of the region studied here not older than about 400 Ma (million years ago). Cave deposits on the other hand allow to infer a minimum age of cave formation, because they are deposited in the cave during or (mostly) after its development. Besides numerous autochthonous (i.e. in situ) sediments and speleothems, also a number of allochthonous (transported into the cave from the surface) sediments are encountered. Burial ages of several quartz-rich allochthonous cave sediments were determined using the radioactive cosmogenic nuclides 26Al and 10Be. The present article provides an insight into this rela tively new dating method (burial age dating) to constrain the age of cave deposits. The current state of knowledge about the timing of cave formation in the Grazer Bergland (Highland of Graz) will be discussed by summarizing the results of two recent papers (Wagner et al., 2010, 2011). Based on these results, conclusions are drawn about the age of the cave levels, relative incision rates of the River Mur and the landscape evolution of the eastern rim of the Alps in general. Sedimentation ages of 0 to about 5 Ma ago are in good agreement with increasingly higher cave levels above the present base level. This in turn reflects the stepwise relative incision of the River Mur. Based on the oldest samples, the onset of karstification and thus the exhumation of the Central Styrian Karst occurred at least 4-5 Ma ago. The oldest level, assigned to an age of at least 4 Ma, is situated some 500 m above the current valley bottom. Therefore, a relative incision rate of the River Mur in the order of only about 100 meters per million year (m/Myr) for the last 4-5 Ma is inferred. A more detailed examination of the levels reveals on average a decrease in the incision rate. Burial ages of ~2.5 Ma are determined only 100 m above the current base level. Moreover, the formation of planation surfaces and terraces in the Grazer Bergland is constrained by the correlation with cave levels and as such an important contribution to the understanding of landscape evolution of this region is made.

Multilevel Caves and Landscape Evolution, 2012, Anthony, Darlene M.

Multilevel caves are formed by periods of water table stability punctuated by changes in the position of the water table. These cave systems are hydrologically linked to regional rivers and can be used to date episodes of river stability and incision. The measurement of cosmogenic radioisotopes in cave sediments yields a burial age for the sediment, which in turn equates to the time of passage abandonment due to water-table lowering. Karst geomorphologists and others are using burial dates from multilevel caves to calculate Plio-Pleistocene rates of river incision, tectonic uplift, and erosion in various parts of the world.

New data on the dolines of Velebit Mountain: An evaluation of their sedimentary archive potential in the reconstruction of landscape evolution , 2012, Ballut Christle, Faivre Sanja

The first approach to the relationships between societies and physical environments on Velebit Mountain shows narrow correlations between spatial distribution of dolines, soil formation, hydric resources, vegetation and land occupation. In 2002, sediment cores have been obtained from different dolines of Velebit Mountain to evaluate the potential of their sedimentary archives in order to reconstruct the landscape history. On the littoral slopes and on the top parts of the mountain, the dolines were difficult to dig due to the presence of rocks in depth. Nevertheless, the cores have been sampled and soil analyses have been made (physical and chemical analyses: colour, grain size, pH, CaCO3, C, N, P, K, Mg, CEC). No dating materials were found. The first results attest to rather homogeneous pedologic processes in each area studied (Kamenica, Stinica, Baške Oštarije and Bilensko Mirevo), but they also indicate colluvial contributions. These contributions differ from one doline to another according to their location and morphology. Dolines reveal themselves to be not very good traps, as the representative nature of their sedimentary archives could be very local. However, the best profile has been obtained at Bilensko Mirevo, which shows a change in the soil nutrient content from an impoverishment in its middle part toward an increase of the soil nutrients in recent parts. Those environmental changes could not be precisely dated, but could be correlated with the 17th to 20th century phase of strong human impact on the Velebit environment and with the rural depopulation observed since the second half of the 20th century.

Landscape evolution in the Tacchi area (Central-East Sardinia, Italy) based on karst and fluvial morphology and age of cave sediments, 2012, De Waele, J. , Ferrarese F. , Granger, D. Sauro, F.


The east-central part of Sardinia (Italy) is characterised by Jurassic
dolomitic mesas (Tacchi, or «table mountains») that overlie a Palaeozoic
basement mainly composed of metavolcanics and phyllites. These mountains
are the remnants of a continuous carbonate cover, dissected by
faults and river erosion, and are now completely isolated hydrological
systems. Most of these rivers have cut valleys more than 200 metres deep
into the Palaeozoic basement rocks, whose slopes are often characterised
by landslides, suggesting their recent oversteepening. Some valleys, on
the contrary, have not reached the base of the carbonate sequence and
appear to be suspended above the deeper incisions, apparently disconnected
by them. Several subhorizontal surfaces can be distinguished on
the table mountains, related to local base level stillstands. Also water
table caves, scattered along the flanks of the mountains over an altitudinal
range of about 200 m, show several stillstands in base level lowering.
26Al and 10Be burial dating of sediments in four caves located at different
elevations on the flanks of the suspended Taquisara Valley show
an Upper Pliocene or Lower Pleistocene age. Thus, this valley appears to
be of Late Tertiary age. The deeper valleys, such as Riu Pardu, that dissect
the Tacchi mountains completely, cutting deeply into the basement
rocks, are much younger, as their unstable slopes suggest. Knickpoint retreat
in Riu Pardu and estimated valley erosion rates suggest the capture
of Riu Pardu by Rio Pelau to have occurred in the last 100 ky.

Reconstructing landscape evolution by dating speleogenetic processes, 2013, Polyak V. J. , Hill C. A.

Speleology and karst geomorphology are making important contributions to evolution of landscapes, thanks to more refined dating techniques, more specialized and advanced instruments, and intensive studies of caves and karst terrains. This chapter provides eight cases where cave and karst studies have made, or are making, new strides in the reconstruction of landscape evolution by dating cave deposits. Some of these study areas include world renowned caves such as Carlsbad Cavern and Lechuguilla Cave in the Guadalupe Mountains of New Mexico, Jewel and Wind caves in the Black Hills of South Dakota, and Mammoth Cave in Kentucky. The authors offer added detail on the caves of the Guadalupe Mountains and Grand Canyon

Results 31 to 45 of 50
You probably didn't submit anything to search for