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 bacteria is simple, colorless one-cell plants, most of which are unable to manufacture their own food using sunlight bacteria are possibly important in caves as synthesizers of food materials from minerals. they are also important as decomposers [23].?

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 pliocene (Keyword) returned 134 results for the whole karstbase:
Showing 16 to 30 of 134
A geological review of Abercrombie caves, 1991, Osborne, R. A. L.

Abercrombie caves (near Jenolan, N.S.W.) have developed in metamorphosed marble forming part of the Upper Silurian Kildrummie Formation. Geological structure and changes in lithology have strongly influenced cave development with pyritic thinly bedded units in the marble being preferentially eroded. The Abercrombie Arch originated as a through cave in Pliocene times, 4-5 millions years ago.

Signification godynamique des rseaux karstiques tags du canyon de Baudinard (moyennes gorges du Verdon, 1992, Blanc, J. J.
GEODYNAMIC SIGNIFICATION OF LEVELLED KARSTIC NETWORKS IN THE BAUDINARD CANYON (VERDON CANYON, FRANCE) - An intense speleogenic activity can be observed in the Baudinard canyon: some levelled systems in relation to the lowering karstic water-table linked to the formation of the canyon, during Messinian, Pliocene and Quaternary periods. An active tectonic framework shows many deformations of the ante-vindobonian surface during the plio-quaternary burrowing canyon phases. Azimuth gallery direction analysis reveals several sorts of drainage network: linear, smoothed with loops, labyrinths and drainage-confluences. Networks are induced by local and successive tectonic actions. The gallery wall deformations are strongly marked by the shrinking stresses and interstrata shearing.

Analyses and interpretation of an industrial multi-channel seismic grid, a 2.3 km-deep industrial well (NMA-1) and two ODP (Sites 715 and 716), have generated new insights into the evolution of the Maldives carbonate system, Equatorial Indian Ocean. The present physiography of the Maldives Archipelago, a double chain of atolls delineating an internal basin, corresponds only to the latest phase of a long and dynamic evolution, far more complex than the simple vertical build-up of reef caps on top of thermally subsiding volcanic edifices. Through the Cenozoic evolution of the Maldives carbonate system, distinct phases of vertical growth (aggradation), exposure, regional or local drowning, and recovery of the shallow banks by lateral growth (progradation) have been recognized. The volcanic basement underlying the Maldives Archipelago is interpreted to be part of a volcanic ridge generated by the northern drift of the Indian plate on top of the hotspot of the island of Reunion. The volcanic basement recovered at well NMA-1 and ODP Site 715 has been radiometrically dated as 57.2 1.8 Ma (late Paleocene) by 40Ar-39Ar. Seismic and magnetic data indicate that this volcanic basement has been affected by a series of NNE-SSW trending subvertical faults, possibly associated with an early Eocene strike-slip motion along an old transform zone. The structural topography of the volcanic basement apprears to have dictated the initial geometry of the Eocene and early Oligocene Maldives carbonate system. Biostratigraphic analyses of samples, recovered by drilling in Site 715 and exploration well NMA-1, show that the Maldives shallow carbonate system was initiated during the early Eocene on top of what were originally subaerial volcanic edifices. The Eocene shallow carbonate sequence, directly overlying the volcanic basement at NMA-1, is dolomitized and remains neritic in nature, suggesting low subsidence rates until the early Oligocene. During this first phase of the Maldives carbonate system evolution, shallow carbonate facies aggraded on top of basement highs and thick deep-water periplatform sediments were deposited in some central seaways, precursors of the current wider internal basins. In the middle Oligocene, a plate reorganization of the equatorial Indian Ocean resulted in the segmentation of the hotspot trace and the spreading of the Maldives away from the transform zone. This plate reorganization resulted in increasing subsidence rates at NMA-1, interpreted to be associated with thermal cooling of the volcanic basement underlying the Maldives carbonate system. This middle Oligocene event also coincides with a regional irregular topographic surface, considered to represent a karst surface produced by a major low-stand. Deep-water carbonate facies, as seen in cuttings from NMA-1, overlie the shallow-water facies beneath the karst surface which can, therefore, be interpreted as a drowning unconformity. In the late Oligocene, following this regional deepening event, one single central basin developed, wider than its Eocene counterparts, and the current intraplatform basin was established. Since the early to middle Miocene, the shallow carbonate facies underwent a stage of local recovery by progradation of neritic environments towards the central basin. The simultaneous onset in the early middle Miocene of the monsoonal wind regime may explain the development of bidirectional slope progradations in the Maldives. During the late Miocene and the early Pliocene, several carbonate banks were locally drowned, whereas others (i.e. Male atoll) display well-developed lateral growth through margin progradations during the same interval. Differential carbonate productivity among the atolls could explain these diverse bank responses. High-frequency glacialeustatic sea-level fluctuations in the late Pliocene and Pleistocene resulted in periodic intervals of bank exposure and flooding, and developed the present-day physiography of atolls, with numerous faros along their rims and within their lagoons

Spectacular towers (average 130 m high) are to be seen in the Lijiang plain near Guilin in middle and upper Devonian limestone forming a downthrown structural panel surrounded by the high relief of a cockpit karst. The limestone was fractured by at least three Triassic and Tertiary tectonic episodes. Statistical analysis of the altitudes of tower summits shows that they are distributed according to a log-normal law with a well marked mode at 250-280 m. This mode is very similar to that of the depression altitudes of the cockpit karst. It was deduced that tower summits and cockpit bottoms show that there was an ancient, relatively flat surface which was the basic level for flow in the surrounding karstic relief (water table at ground level). Fall in this ground water caused preferential karstic breakdown in very fractured zones, leaving the stronger blocks. This subsidence must have taken place in stages, as is shown by Pliocene and lower Quaternary fossil cavities at various altitudes of the towers. Observation of fracturing in the field, in aerial photographs and satellite images show that the edges of the towers are mainly transverse faults with sub-vertical planes

Rospo Mare (Adriatique), un palokarst ptrolier du domaine mditerranen, 1993, Dubois P. , Sorriaux P. , Soudet H. J.
The oil paleokarst of Rospo Mare (Adriatic Sea) The oil field of Rospo Mare is located in the Adriatic Sea, 20 km of the Italian coast. The reservoir lies at the depth of 1300m and consists of a paleokarst of Oligocene to Miocene age, which developed within Cretaceous limestones, now covered with 1200m of mio-pliocene sequences. The oil column is about 140m high. The karstic nature of the reservoir was identified through vertical, cored drill holes which allowed the analysis of the various solutional features and the sedimentary infilling (speleothems, terra rossa, marine clays), as well as their vertical distribution. Erosion morphology at the top of the karst is highly irregular, including paleovalleys as well as many pit-shaped sinkholes. Observations concerning the upper part of the reservoir were compared to a paleokarst of the same age, outcropping widely onshore, in nearby quarries. Detailed knowledge of that morphology through geophysics helped to optimise the development of the field through horizontal drilling. The paleokarst of Rospo Mare is an integral part of the pre-miocene paleokarst assemblages of the periphery of the Mediterranean, which were formed in tropical conditions.

Alpine karsts. Genesis of large subterranean networks. Examples : the Tennengebirge (Austria) - the Ile de Crémieu, the Chartreuse and the Vercors (France), PhD Thesis, 1993, Audra, Philippe

This work, based on the study of several underground alpine networks, aims to propose some milestone in the history of these karstic regions.

The first part of the work is made up of three regional studies.

The Tennengebirge mountains are a massif of the limestone High Alps in the region of Salzburg in Austria. A cone karst close to the base level developed in the Neogene. Streams from the Alps fed the karst, resulting in the huge horizontal networks of which the Eisriesenwelt provides evidence. During the successive phases of upthrust, the levels of karstification, whether on the surface or deeper down, settled into a tier pattern, thus descending in stages from the base level. From the Pliocene era onwards, thanks to an increase in potential, alpine shafts replace the horizontal networks. The formation of these shafts is more pronounced during glaciation. The study of the Cosa Nostra - Bergerhöhle system developing 30 km of conduits on a gradient reaching almost 1 500 m provides a fairly full view of the karstification of this massif. It includes the horizontal levels developed in the Miocene and the Plio-Pleistocene, joined together by vertical sections. The most noteworthy features of the Tennengebirge, as in the neighboring massifs, lie first and foremost in the extreme thickness of the limestone which has recorded and immunized the differents steps of karstification. Secondly, the size of the networks can be, for the most part, accounted for by the contribution of allogenous waters from the streams of the Neogene and the glaciers of the Pleistocene. Generally sudden and unexpected, these flows of water engendered heavy loads (up to 600 m), simultaneously flooding several levels. To a lesser extent, the situation is similar today.

The Ile de Cremieu is a low limestone plateau on the western edge of the Jura. Due to its location in the foothills, the lobes of the Rhône glacier have covered it up, obliterating the surface karst. However, widespread evidence of anteglacial morphologies remains : paleokarst, cone karst, polygenic surface. Because of glacial plugging, access to the underground karst is limited. The main cavity is the cave of La Balme. Its initial development dates back to an early period. The morphological study has permitted the identification of several phases which go back to the Pleistocene and which are related to the Rhône glacier. The latter brought about modifications in the base level by supplying its merging waters as well as moraine material. These variations in the base level shaped the drainage structure. The underground glacial polishes are one of the noteworthy aspects recorded.

The massives of the Moucherotte and dent de Crolles belong to the northern French Prealps. They conceal large networks, respectively the Vallier cave and the Dent de Crolles. They were formed in the early Pliocene after the final orogenic phase and are in the form of horizontal conduits. The upthrust, which brought about the embanking of the Isère valley, left them in a perched position by taking away the basin which fed them. They were later, however, able to take advantage of waters from the Isère glacier during a part of the Pleistocene. The Vallier cave contains particularly glacio-karstic sediments of the lower Pleistocene, representing unique evidence of glaciation during this period. The vertical networks were put in place at the end of the Pliocene with the increase in karstification potential ; they underwent changes in the Pleistocene due to the effect of autochton and allogenous glaciers.

The second part of the work deals in general with the various forms and processes of karstification, sometimes going beyond the Alps. The study of cave deposits is a privileged tool in the understanding and reconstruction not only of the history of the networks but also the regional environment. The dating of speleothems by the U / Th method has very ofen given an age of over 350 000 years. The age of the networks is confirmed by the use of paleomagnetism which has yielded evidence of speleothems and glacio-karstic sediments anterior to 780 000 years. Anisotropic measurements of magnetic susceptibility have been used to distinguish the putting into place of glacio-karstic deposits by decantation.

Measurements of calcite rates lead to a typology of sediments based on their nature and carbonate content (rehandled weathered rocks, fluvial sands, carbonated varves, decantation clays). Granulometry confirms this differenciation by supplying precise details of transport and sedimentation modes : suspension and abrupt precipitation of clay, suspension and slow decantation of carbonated varves, suspension and rolling together with a variable sorting of sand and gravel. Mineralogical analyses oppose two types of detrital deposits. On the one hand, the rehandling of antequaternary weathered rocks extracted by the karst as a result of scouring during environmental destabilization and on the other hand, sediments characteristic of the ice age of the Pleistocene. The latter are not highly developed and their arrival in the karst is always later. Examination of heavy minerals, the morphoscopy of quartz grains and study of micromorphologies on thin blades provide precise details of conditions of evolution. The use of these methods of investigation allows for an accurate definition of the features of the evolution of the differents types of fillings, particularly speleothems, rehandled weathered rocks as well as carbonated varves. This wealth and complexity are emphasized by a detailed study of the sedimentary sequences of the Vallier cave and of the Bergerhöhle.
Speleogenesis is approached last of all in the light of above study. Emphasis is placed on the major part played by corrosion in the temporarily phreatic zone and on its many consequences (multi-level concept, simultaneous evolution of levels, origin of deep waterlogged karsts…).
Varia tions in the base level have induced karstification in contexts in which the potential was weak. These were followed by periods of increased potential to which were added the effects of glaciation. Perched horizontal levels belong to the first stages which ended in the early Pliocene, whereas alpine shafts developed in the second context. The role of structure and the parameters governing the shape of conduits (pits, meanders, canyons) are also dealt with. The different parts of the karst are borne in mind when dealing with the strength of karstic erosion during the ice age. It notably appears that it is weak on the crests and more or less non-existent in the deep parts of the karst which are liable to flooding. Finally, a preliminary analysis of an observation of neotectonic traces is presented.

Rapports entre la karstification _primditerranenne et la crise de salinit messinienne, lexemple du karst lombard (Italie), 1994, Bini, A.
The Mediterraean dessiccation theory suggests that during the Messinian the Mediterranean sea lad almost completely dried up did a thick succession of evaporites was laid down Due to dessiccation the erosional base level through the whole Mediterranean area was lowered, with the consequent development of long and deep fluviatile canyons (e.g. Nile, Rhne, Var, etc). This lowering strongly affected karst evolution This paper concerns the karst in Lombardy, around the southalpine lakes. The old evolutionary models, predating dessiccation theory, assume that the lacustine valleys were scoured by the quaternary glaciers. ln this case the karst should have been characterized by some features, like for example the altitudinal cave distribution as a consequence of the valley lowering after each glaciation. Seismic experiments through the lakes and their tributaries have shown that these valleys are deep fluviatile canyons. The study of caves has demonstrated that the caves themselves predate the entrenchment of the valleys and the glaciations. During the latter the caves were filled up and emptied several times, without any modifications of their inner morphology, including stalactites. Moreover the U/Th age determinations indicate that a great number of concretions are older than 350 ky, and that a few are older than 1.5 Ma. As a conse-quence, a general model of karst evolution can be proposed. The former karstic drainage system developed after the Oligo-Miocene emersion. Paleogeography obviously diffe-red from the present day landscape but the main valley had already been scoured. During the Messinian the dramatic lowering of base level determined major changes in karstic evolution and a reorganisation of the karst drainage system that was consequently lowered considerably. The Pliocene transgression determined a new karst evolution, after which a great number of caves were located well below the sea level base. This evolution occurred during hot and wet climate period, with seasonal high flows and relevant discharges of the karstic rivers The great caves of the Lombardian karst developed within the climatic stage.

The Rospo Mare oil field is located in the Adriatic Sea, 20 km off the Italian coast. The reservoir lies at a depth of 1300 m and consists of a paleokarst oi Oligocene to Miocene age which developed within Cretaceous limestones, now covered by 1200 m of Mio-Pliocene sequences. The oil column is about 140 m 8 high. The karstic nature of the reservoir was identified through vertical, cored drill holes which allowed us to analyse the various solution features and the sedimentary infilling (speleothems, terra rossa, marine clays), as well as their vertical distribution. Erosion morphology at the top of the karst is highly irregular, including in particular paleovalleys as well as many pit-shaped sink holes. Detailed geophysical knowledge of that morphology helped to optimize the development of the field through horizontal drilling. Observations concerning the upper part of the reservoir were compared to a palaeokarst of the same age, outcropping widely onshore, in quarries located nearby. The Rospo Mare paleokarst is an integral part of the ante Miocene paleokarst assemblages of the periphery of the Mediterranean which were formed in tropical conditions. Only the fractures enhanced by meteoric water during the formation of the karat are important for reservoir connectivity. During the formation of the karst there were several phases of dissolution and infilling which modified the geometry of the open fissures and only these fractures play an important role in the reservoir drainage. Vertically we can distinguish three very different zones from top to bottom: at the top the epikarst (0-35 m) in a zone of extension. All the fractures have been enlarged by dissolution but the amount of infilling by clay is substantial. The clays are derived either from alteration of the karat fabric or by deposition during the Miocene transgression; the percolation zone (15-45 m) is characterized by its network of large fractures vertically enlarged by dissolution which corresponds to the relict absorption zones in the paleokarst. These fractures, which usually have a pluridecametric spacing, connect the epi-karst with the former sub-horizontal river system. This zone has been intersected by the horizontal wells during the field development. In this zone there are local, horizontal barriers oi impermeable clay which can block vertical transmissibility. In these low permeability zones the vertical fractures have not been enlarged due to dissolution hence the horizontal barrier; the zone of underground rivers (35-70 m) is characterized by numerous horizontal galleries which housed the subterranean ground water circulation. When these fissures are plurimetric in extent this can lead to gallery collapse with the associated fill by rock fall breccia. This can partly block the river system but always leaves a higher zone of free circulation with high permeabilities of several hundreds of Darcys. These galleries form along the natural fracture system relative to the paleohydraulic gradient which in some cases has been preserved. The zone below permanent ground water level with no circulation of fluids is characterized by dissolution limited to non-connected vugs. Very locally these fissures can be enlarged by tectonic fractures which are non-connected and unimportant for reservoir drainage. Laterally, only the uppermost zone can be resolved by seismic imaging linked with horizontal well data (the wells are located at the top of the percolation zone). The Rospo Mare reservoir shows three distinct horizontal zones: a relict paleokarst plateau with a high index of open connected fractures, (area around the A and B platforms); a zone bordering the plateau (to the north-east of the plateau zone) very karstified but intensely infilled by cap rock shales (Miocene - Oligocene age); a zone of intensely disturbed and irregular karst paleotopography which has been totally infilled by shales. The performance of the production wells is dependent on their position with respect to the three zones noted above and their distance from local irregularities in the karst paleotopography (dolines, paleovalleys)

The Cayman Unconformity, which separates the Pedro Castle Formation (Pliocene) from the underlying Cayman Formation (Miocene), is a sequence boundary that developed during the Messinian, when sea level was at a lowstand due to glaciation in the Southern Hemisphere. By the end of the Messinian, Grand Cayman was an atoll-like island that had an elevated peripheral rim that was up to 41 m above the central depression. The Cayman Formation contains paleocaves and paleosinkholes that were linked to the Cayman Unconformity. The topography on the Cayman Unconformity is attributed to erosional processes, because (1) there is no evidence of carbonates that formed by constructional processes (i.e., reefs, dunes) in the elevated peripheral rim, and (2) there is ample evidence of dissolutional features in the Cayman Formation. The topography developed on the interior of Grand Cayman during the Messinian was uneven. A deep, basin-like depression, with its base as much as 50 m below the peripheral rim, formed on the western part of the island. By comparison, the floor of the depression on the eastern part of the island was 20-30 m higher. The difference in the topography, which is a reflection of the amount of bedrock dissolution, suggests that the effective rainfall was highest over the western part of the island. The relief on the Cayman Unconformity and associated structures shows that base level during the Messinian karst development was at least 41 m below present-day sea level. This is also provides an estimate of the Messinian lowstand position because the base level in oceanic karst settings is usually controlled by sea level

Signification des remplissages des karsts de montagne, quelques cls lusage des splologues, 1995, Audra, P.
This paper is intended to cavers in order to help them identify the most significant mountain karst infillings. Carbonated varves sedimentation occurs during floodings in glacial environment. The varves block the deep parts of the networks. Pebbles sealings show a powerful erosion in the vadose zone, near glacial sinkholes. Gelifract spreadings are indicators of frost and snow action in periglacial environment. Reworked weathered rocks are the most ancient deposits, inherited from tertiary warm phases when karstification occurred under regolith covers. Their clearing is partly simultaneous with cave systems elaboration, in relation to the alpine uplift, during Pliocene. Speleothems are also warm or temperate climate indicators. Crystalline morphology reflects environmental characteristics, while their surface sight could have been smoothed during discharge reactivations. Finally, some infillings could have recorded neotectonic movements: broken speleothems, deformed clastic sediments, etc.

Etapes et facteurs de la splogense dans le sud-est de la France, 1995, Blanc, J. J.
The examination of karstic erosion surfaces and of some caves presents three stages of unequal duration in the speleogenesis processes : 1) Oldest paleokarsts linked to a tropical and oxydizing climate (Cretaceous, Eocene, Oligocene and Miocene) are affected by the tectonic effects in relation with the western European and liguro-provencal riftings, the mediterranean opening phases and the main karstic levelling. 2) The Messinian crisis, characterized by a significant lowering of the water-table level, is responsible for a major vertical network development and the first canyon sinking phase; hence the erosion of the high surfaces and the drying up of networks. The formation of new over-sized karst is the result of this evolution. 3) From Pliocene (5.3 My) to Quaternary and present time (passive mediterranean margins), the karstic evolution tends towards new drainages and volumes adjusted to the next climatic and eustatic control, with several oscillations and discontinuities. After a compression period, there is a slowing down of the tectogenesis. We can observe orientation flow changes and speleogenesis induced by cold and wet climatic phases. From Tardiglacial times, speleogenesis mechanisms have slowed down.

La plate-forme du Yucatn (Mexique), 1995, Heraudpia, M. A.
The Platform of the Yucatan peninsula, south of Mexico, is constituted by a tertiary carbonated series (Eocene to Pliocene). The karst landforms are a "Kuppenkarst" whose positive reliefs are more conspicuous in the centre because of greater altitude (0 to 400 m). Most caves are developed under the base level. The cenote corres-ponds to drowned pits which can be 100 m deep or more. The flooded caves, like Nohoch Nah Chich (40km long), are the longest in the world. The history of karstification began during the Tertiary, between the end of Eocene to Pliocene in relation with uplift. The crypto-dissolution occurs under an alte-ritic cover which comes from a former silicated detritic cover (south peninsula crystalline massif). Speleogenesis depends on the halocline i.e. mixing corrosion zone (salt water/fresh water) and the fluctuations of the sea level.

Sannur Cave: A Crescent shaped cave developed in Alabaster formation in Eastern Desert, Egypt, 1995, Gü, Nay G. , Elbedewy F. , Ekmekci M. , Bayari S. , Kurttas T.
An expedition to Egypt set out to explore the Wadi Sannur where no speleological work had taken place. The most notable karst feature identified to date is the Sannur Cave, the largest subterranean chamber known in Egypt. It is situated about 70 km to the southeast of Beni-Suef city in the remote Wadi Sannur of the Eastern Desert where the main rock units belong to Eocene and Pliocene periods. The Eocene is represented by limestone including alabaster which is known to be quarried first by the ancient Egyptians. Sannur Cave is first explored during blasting in the alabaster quarry which caused an artificial entrance to the cave. The cave is a single crescent shape chamber approximately 275 m long and can be arbitrarily divided into two sectionshaving different characteristics; left side gallery and right side gallery. Few speleothems occur in the left side gallery while the right side gallery is decorated intensively with many kinds of spelethem including stalagtites, stalagmites, flowstones, microgours, helictites and soda-straws etc. In addition to surveying the cave, based on the geologic, structural and morphologic observation inside and outside the cave some interpretations on the paleoenvironment an the origin of the cave. Surveying was performed with grade 5D according to BCRA Gradings.

Origin of the Danube-Aach system, 1996, Hotzl H. ,
The Swabian Alb formed by an Upper Jurassic carbonate sequence is the most extensive karst area of Germany. The western part is crossed by the upper Danube River. It represents an old, mainly Pliocene, drainage system that is now restricted by the young Rhine system. The low base level of the upper Rhine graben causes a strong headward erosion. Since the Upper Pliocene, the Danube has lost more than 90%, of its headwaters. The underground Danube-Aach karst system of the western Alb represents the last capture of the Rhine, leading periodically to a complete loss of water in the upper Danube. The seepage of this water, together with the huge karst catchment area, supplies the strong discharge of the Aach Spring, forming the largest spring of Germany with an average discharge of 8.5 m(3) s(-1)

Geomorphological evidence for anti-Apennine faults in the Umbro-Marchean Apennines and in the peri-Adriatic basin, Italy, 1996, Coltorti M, Farabollini P, Gentili B, Pambianchi G,
The Apennines are a relatively recent mountain chain which has been affected by uplift movements since the Upper Pliocene. In fact the remnants of an “erosional surface”, reduced close to base level, is preserved at the top of the relief. There is no general agreement on the geodynamic stress field and mechanisms which are creating the chain. However, it is largely accepted that uplift occurred together with the activation, on the western side of the chain, of extensive faults, oriented in the Apennine direction (NW-SE), which have been linked to the opening of the Tyrrhenian sea. A great debate is going on about the presence and significance of anti-Apennine faults (NE-SW) which have been observed by some authors but completely denied by others.The main evidence is represented by[ (1) block faulting of the remnants of the “erosional surface”. Along the Marchean Ridge, more elevated relief, delimiting relatively depressed areas, was created in correspondence with the Sibillini Mts. and Mt. S. Vicino. Similar evidence has been found in the Umbro-Marchean Ridge. Locally more than 1500 metres of displacement have been observed between more and less uplifted remnants. (2) Block faulting of fan deltas and related beaches, of Sicilian to Crotonian age, with more elevated sediments preserved between the Tronto and Tenna rivers and between the Musone and Esino rivers. Maximum displacement along a transect parallel to the coast is 200 metres. (3) fault-scarps affecting the Middle Pleistocene river terraces, as observed along the Esino, the Tronto, the Chienti and the Tenna river valleys. Maximum displacements are in the order of 50 metres. (4) Faulting of horizontal karst galleries and reorientation of the cave network, as in the Frasassi Gorge. Maximum displacements are about 100 metres. (5) Captures and alignments in the drainage network of the main river courses. (6) Large-scale gravitational movements, as in the Ancona landslide, and along the Chienti and Esino rivers.Their activation occurred in most cases after the Lower Pleistocene and although their displacements may be of relatively limited extent, dispite their recent activity, they played a major role in the modelling of the landscape. These faults display transtensive, extensional and trascurrent movements. Apart from the controversial geodynamic significance of these faults, from a geomorphological point of view they must be considered transverse elements of the stress field from blocks more or less uplifted along the Apennine chain.The importance and timing of activity of these faults in the Quaternary geomorphological evolution of the Umbria-Marchean Apennines is demonstrated using evidence usually underestimated by structural geologists, which can contribute to a debate based on a multidisciplinary approach

Results 16 to 30 of 134
You probably didn't submit anything to search for