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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 phreatic rise is the upward movement of the water table [16].?

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Featured articles from Cave & Karst Science Journals
Chemistry and Karst, White, William B.
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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;
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Your search for plio-quaternary (Keyword) returned 19 results for the whole karstbase:
Showing 1 to 15 of 19
Prsentation du Causse Comtal (Aveyron), 1987, Solier, P.
THE " CAUSSE COMTAL " (AVEYRON, FRANCE): GEOLOGY, HYDROGEOLOGY AND INVENTORY OF MAIN CAVES - The " Causse Comtal " (S = 265 km2) forms a sedimentary bridge between the " Causses du Quercy " in the west and the " Grands Causses " in the east. With a middle humid climate (P = 1000 mm/y, T = 9,4 C, Evap. = 450-500 mm/y), this plateau karst presents two aquifer levels in the Lower and Middle Jurassic separated by a marly layer. These formations cover a paleozoic basement (sandstone, argillite from Carboniferous and Permian, crystalline rocks). The hydrogeological basins are controlled by E-W reverse faults due to the N-S pyrenean compression. The main spring is near Salles-la-Source in the western part (average discharge: 840 l/s; flood : 10 m3/s); it drains a 50-55 km2 area. The morphological and speleological evolution is subordinated to an erosion surface from Upper Cretaceous - Tertiary. Often stopped up (blocking), the numerous fossil caves probably date from the end of Cenozoic era. The large subterranean passages (active or semi-actives galleries; ex.: Tindoul de la Vayssire) are plio-quaternary.

Notectonique dans le karst du N-O du lac de Thoune (Suisse), 1990, Jeannin, P. Y.
Neotectonic in the karst north of Lake Thoune (Switzerland) - The karstic area north of Lake Thoune is part of the "Border Chain" of the Swiss Alps (Cretaceous, Helvetic). It comprises large caves coming from two catchments. The first one pours out at the Beatushhle; more than 15 km of galleries are known in this area. The second one contains the Sieben Hengste - Hohgant - Hohlaub - Schrattenfluh region, it pours out at the Btterich and Gelberbrunnen springs, by Lake Thoune. It includes the very large "Sieben Hengste - Hohgant cave System" (length: 115 km; depth: 1050 m); the Brenschacht (length: >10 km; depth: 950 m), as well as several other important caves more than 1 km length. Recent shifts along faults were mainly measured in the Sieben Hengste Cave System. Neotectonic indication were of the following types: gallery sections displaced by the fault shifts, displaced pillar structures or shifted, inclined or broken speleothems. The fault movements were placed on a time scale according to the genetic evolution of the region. It indicates that there were three phases of movement, which greatly affected the underground flows and karstification. The geometric and dynamic analysis of the measured shifts and slikken-slides also indicates three phases of movements. The strain direction, causing these movements, was determined. Thus, three plio-quaternary tectonic phases were found: an alpine compressive SSE-NNW phase, followed by an extensive SSE-NNW phase and then again by a compressive one.

Karstification et volution palogographique du Jura, 1991, Bienfait, P.
KARSTIFICATION AND PALEOGEOGRAPHICAL EVOLUTION OF THE JURA (Fr.) - The karstification started at the beginning of the Tertiary, and the process is still going on today. During the Eocene, modifications brought about under the tropical climate resulted in siderolithic deposits (siliceous sands, ferruginous soils), which can be found in some fossil karsts. In the Oligocene, active tectonics modified the Eocene surface. Erosion during the Miocene levelled the Jura Mountains into a peneplain even though the climate remained tropical. Toward the end of the Miocene, present-day structure and landforms were produced when the main folding, subjected at the same time to powerful erosion, occurred. During the Upper Pleistocene the climate became cooler and wetter. At least two glacial periods have been recognised in the Pleistocene. Present-day karst landforms and most of the caves can be considered as being shaped during the Plio-Quaternary. The karst fillings of the Quaternary provide evidence of the extension of the Wrm and Riss glaciers.

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.

Interprtation morphomtrique et splo_gense : exemple de rseaux karstiques de Basse-Provence (directions de galeries, modle et maillage structural), 1997, Blanc Jeanjoseph, Monteau Raymond
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 "pyreneo-provenale" 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 Ma), 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 Tete du Cade networks.

The carbonated palaeosurface of the ''Arbailles'' massif (Pyrennes-Atlantiques): An example of Neogene hydrographic network dried up by uplift and karstification, 1997, Vanara N. , Maire R. , Lacroix J. ,
The ''Arbailles'' massif constitutes a folded area of Jurassic and lower Cretaceous limestones, which belongs to the north-Pyrenean zone. The top karst surface was dug by a palaeofluviatile system from the Albian marlous limestone cover and dried up by uplift (infiltration). This hydrographic network recorded the main events of uplift by staged valley levels (950, 850, 730 and 380 m). Some old endokarstic infillings can be seen on the residual cone karst showing the erosion of a thick limestone layer. The alterite pockets contain elements of former cuirasses which originated in former hydromorphic depressions. These polygenic deposits contain two kinds of mineral families coming from alterations of both Albian marlous limestones and Triassic Mendibelza conglomerates. During the Upper Oligocene and Miocene (after the Middle Lutetian orogenesis), the ''Arbailles'' massif was a chemical weathering surface in a wet and tropical climate in relation upstream with Mendibelza conglomerates and downstream with Cenomanian flyschs. The Plio-Quaternary uplift, of 1000 m, caused the alterite and cuirasse erosion, the drying up of the fluviatile system (Lower Pleistocene), the genesis of a cone karst and the formation of underground systems

Rapport entre karst et glaciers durant les glaciations dans les valles pralpines du sud des Alpes, 1998, Bini Alfredo, Tognini Paola, Zuccoli Luisa
At least 13 glaciations occurred during the last 2.6Ma in the Southern pre_alpine valleys. The glaciers scouring alpine and pre-alpine valleys had all the same feature, being valley temperated glaciers. Their tracks and feeding areas were always the same, just like the petrological contents of their deposits. Contrary to previous assumptions until a few years ago, the origin of these valleys and of the lakes occupying the floor of some of them (Orta, Maggiore, Como, Iseo, Garda Lakes) is due to fluvial erosion related to Messinian marine regression. The valley slopes modelling is Messinian in age, too, while most caves are older. As a general rule, glaciers worked on valley slopes just as a re_modelling agent, while their effects were greater on valley floors. The karstic evolution began as soon as the area was lifted above sea level (upper Oligocene - lower Miocene), in a palaeogeographical environment quite different from the present one, although the main valley floors were already working as a base level. During Messinian age, the excavation of deep canyons along pre-existing valleys caused a dramatic lowering of the base level, followed by a complete re-arrangement of the karstic networks, which got deeper and deeper. The Pliocene marine transgression caused a new re-arrangement, the karst network getting mostly drowned under sea level. During these periods, the climate was hot-wet tropical, characterised by a great amount of water circulating during the wet season. At the same time tectonic upliftings were at work, causing breaking up of the karst networks and a continuous rearrangement of the underground drainage system. In any case, karstic networks were already well developed long before the beginning of Plio-Quaternary glaciations. During glaciations, karst systems in pre-alpine valleys could have been submitted to different drainage conditions, being: a) isolated, without any glacial water flowing; b) flooded, connected to the glacier water-filled zone; c) active, scoured by a stream sinking at glacier sides or in a sub glacial position. The stream could flow to the flooded zone (b), or scour all the unflooded system long down to the resurgence zone, the latter being generally located in a sub glacier position. The glacier/karst system is a very dynamic one: it could get active, flooded or isolated depending on endo- and sub-glacial drainage variations. Furthermore, glaciers show different influences on karstic networks, thus working with a different effect during their advance, fluctuations, covering and recession phases. Many authors believe, or believed, the development of most surface and underground karst in the Alps is due to glaciations, with the last one held to be mostly responsible for this. Whatever the role of glaciers on karstic systems, in pre-alpine valleys caves, we do not have evidence either of development of new caves or of remarkable changes in their features during glaciations. It is of course possible some pits or galleries could have developed during Plio-Quaternary glaciations, but as a general rule glaciers do not seem to have affected karstic systems in the Southern pre-alpine valleys with any remarkable speleogenetic effects: the glaciers effects on them is generally restricted to the transport of great amounts of debris and sediments into caves. The spotting of boulders and pebbles trapped between roof stalactites shows that several phases of in- and out-filling of galleries occurred with no remarkable changing in pre-dating features, including cave decorations. The presence of suspended karst systems does not prove a glacial origin of the valleys, since most of them pre-date any Plio-Quaternary glaciation, as shown by calcite cave deposits older than 1,5Ma. The sediments driven into caves might have caused a partial or total occlusion of most galleries, with a remarkable re-arrangement of the underground drainage system. In caves submitted to periglacial conditions all glaciations long, we can find deposits coming from weathered surface sediments, sharp-edged gelifraction debris and, more rarely, alluvial deposits whose origin is not related to the circulation of the glacial meltwater. In caves lower than or close to the glaciers limit we generally find large amounts of glacier-related deposits, often partly or totally occluding cave galleries. These sediments may be directly related to glaciers, i.e. carried into caves by glacial meltwaters, resulting from surface glacial deposit erosion. They generally show 3 dominant facies: A) lacustrine deposits; B) alluvial deposits and C) debris flow deposits facies. The only way of testing the soundness of the forementioned hypothesis is to study the main characters and spreading of cave sediments, since they are the only real data on connection of glaciers to endokarst networks.

Seismotectonic versus man-induced morphological changes in a cave on the Arrabida chain (Portugal), 1999, Crispim Ja,
Distinctions between cave morphologies originating from seismic or active tectonics and those generated by natural elastic breakdown or by human activity must be made using unambiguous interpretative criteria. Easily accessible caves in particular, which may have been visited for centuries or millennia, or caves located near engineering works or quarries using great quantities of explosives, may have broken speleothems, breakdowns or detachment joints unrelated to seismic events or tectonic movements. Zambujal cave lies near neotectonic and seismic structures associated with a Plio-Quaternary 200 m uplift of the Arrabida chain and has suffered impacts resulting from quarrying, followed by possible vandalism. It is thus an example for which it is difficult to decipher morphological agents as there is the possibility that identical forms have been generated by several causes, which may have repeated at different episodes of its evolution. However, a careful morphological interpretation makes it possible to accept the existence of two seismic episodes, an 'ancient' one and a 'modern' one. The detection of other episodes between these is only possible using absolute dating. (C) Elsevier, Paris

Landscape evolution and the preservation of tectonic landforms along the northern Yammouneh Fault, Lebanon, 1999, Butler Rwh, Spencer S,
The Yammouneh Fault is commonly considered to be the principal active strand of the Dead Sea Transform in Lebanon -- an inference reached primarily from interpretations of the geomorphological expression of the fault on satellite images. However, new geological field observations show the Yammouneh Fault to be sealed stratigraphically by the Homs Basalt, dated using new K-Ar ages at 5.2-6.5 Ma. Drainage systems which link to the pre-Homs Basalt palaeosurface show evidence of fault disruption. Those valleys incised into the basalt show no evidence for transcurrent offsets. The inferred left-lateral displacement of c. 45 km on the Dead Sea Transform that post-dates the Homs Basalt is presumed to have bypassed to the west of Mount Lebanon. These linked geological and geomorphological studies indicate that landscape evolution can be exceptionally slow in northern Lebanon. Faceted spurs, poljes and offset drainage along the Yammouneh Fault across Mount Lebanon, evident on satellite images, are interpreted as being of Miocene age and are not indicative of Plio-Quaternary displacements on the fault. Much of the Lebanese tectonic landscape has thus remained stable for many millions of years, although locally incised during large-scale uplift of the Mount Lebanon range. Presumably landscape insensitivity reflects the arid climatic conditions together with inhibited run-off due to the regional karst system

Plio-Quaternary karst development in the French Prealps: Speleogenesis and significance of cave fills, 2000, Audra P.
Three French cave systems in the Prealps in the Vercors and Devoluy mountain areas are described. It is possible to reconstruct their evolution by analyzing their morphology and by dating the karst fill using paleomagnetism and U/Th. Cave development began at the end of the Miocene during uplift when inclined tubes formed in the epiphreatic zone. Later the tubes were partially blocked by weathered detritus from the surface. Uplift diverted former recharge away from the caves and extensive calcite deposition occurred. The cave systems were reactivated during glaciations, with flooding to considerable depths. The epiphreatic zone was blocked with calcareous varves from meltwater. During interglacial periods, either calcite deposition or dissolution occurred, depending on the altitude and density of the soil cover.

Geomorphologic evolution of a coastal karst: the Gulf of Orosei (central-east Sardinia, Italy), 2004, De Waele, Jo

In the past ten years cave surveying has allowed better understanding of speleogenesis in the Orosei Gulf (Central-East Sardinia, Italy), one of the most important coastal karst areas of Italy. Surface geomorphologic research has been accompanied by subterranean and submarine landform analysis in order to try and understand the evolution of this coastal karst since its emersion in Upper Eocene. The main factors influencing the geomorphic processes are lithology, tectonics, palaeo-climate and sea level changes. The study of several important cave systems demonstrates a complex geological history with karst processes that started in Early Tertiary and accelerated during Plio-Quaternary.


Evaluating the impact of quarrying on karst aquifers of Salento (southern Italy), 2007, Le Rose M. , Parise M. , Andriani G. F. ,
This paper describes a case study in the Salento karst (Apulia, southern Italy) in a site that has been intensively used to quarry limestones in the last 30 years. After quarrying activity had stopped, the site was transformed into legal and illegal landfills where solid and liquid wastes have been repeatedly dumped, with serious consequences for the groundwater resources. In this paper, through a geological, petrographical and hydrogeological approach, we attempt to assess the consequences of the anthropogenic activities on the local hydrogeology, with particular regard to the surficial aquifer that is contained in the Plio-Quaternary calcarenites cropping out in the area. Application of some well-known methods to assess the vulnerability of aquifer systems to contamination by human activities (DRASTIC, SINTACS, LeGrand and GOD) highlights the limits of such an approach in karst environment, and the necessity to include in the methods data strictly related to the peculiarity of karst. This is further evidenced by application of the EPIK method, specifically designed for karst areas. The final part of the paper focuses on the need of a thorough understanding of the hydrogeological setting for a better management and policy action of karst environments

Morphology and origin of coastal karst landforms in Miocene and Quaternary carbonate rocks along the central-western coast of Sardinia (Italy), 2009, De Waele Jo, Mucedda Mauro, Montanaro Luca

In the area of Punta Funtanas (Arbus, Central-West Sardinia) somesmall surfaces ofMiocene limestones crop out, partially covered with Quaternary calcarenites and Plio-Quaternary basalts. The biggest of these outcrops forms a fossilwave-cut shore platformof up to 50m wide with an altitude above sea level of approximately 4–5m. On this platformawide variety of dissolution landforms can be observed. Thesemorphologies are related to the influence of the seawater (zone of wave action, marine splash and spray zone, up to progressively more continental environments) and to biokarst processes (erosional action ofmarine organisms, algae andmicro-organisms) and are arranged in bands parallel to the coast, corresponding to different morphological zones.

This paper describes all the karst landforms observed in this coastal area from a morphological and genetic point of view.


OBSERVATIONS OF PLIOCENE KARSTS FOSSILIZED BY QUATERNARY EOLIAN SILTS IN THE MATMATA MOUNTAINS (SOUTH-EAST TUNISIA), 2012, Sghari, Abdeljalil

The submeridional Dahar chain in southeastern Tunisia is over 200 km long. It is separated from the Mediterranean Sea by the Jeffara plain with some tens of kilometers in width. This landscape continues to the South into Libya, but to the North, the chain ends with the Matmata mountains which form a plateau slightly inclined to the west and some 10 km wide. The eastern scarp shows a mainly calcareous geological stratigraphy from Upper Permian to the Senonian. The Dahar-Matmata structure belongs to the Sahara platform and shows a hiatus during the whole Tertiary, since it was emerged since Upper Cretaceous. The Tunisian Atlas nearby shows a completely different paleogeographic evolution, with a complete Tertiary series and a later Plio-Quaternary structuration. These two paleogeographic domains of Southern Tunisia, the Sahara Atlas and the NE border of the Sahara platform, were influenced by the Messinian crisis (5.9 Ma to 5.3 Ma). This was expressed by the collapse of the Mediterranean Sea level, profoundly modifying the fluvial dynamics with an inversion of the erosional system, from normal erosion to regressive erosion. It results a deepening of canyons in the downstream part and a deepening of the watercourses in the upstream part. The geological structures in the Messinian have been deeply affected by these large eustatic changes, with an incision of cluses in the Atlas and the deposition of a thick clayeysandy series that we could recently link to deltaic systems and Gilbert deltas. The re-establishment of seaways between the Atlantic and the Mediterranean, and the subsequent infill in the Lower Pliocene (Zanclean transgression), with an important inpact in Southern Tunisia, had multiple consequences in that region. The newly adjusted sealevel, together with a more humid climate that was confirmed by faunal and floral extension oof tropical plants in Northern Africa, stimulated an important karstification of the limestone areas. In the Dahar chain, caves, dolines, karstic depressions or karstic dry valleys emerged, the most spectacular ones being found in the Matmata Mountains. The karstic depressions are the forms that represent best this Pliocene karstification that surely was interrupted in an early stage, because localized endokarstic forms had not enough time to develop. So the karstification seems to have been active in Matmata from 5.4 to 4.0 million years, i.e. two times as long than the duration of the Messinian crisis. The interruption of karstification is due to an increase in temperature and dryness, which even gets more intense during the Pliocene, pulverizing the soils. Already at the beginning of the desertification, a calcareous crust forms by rapid cristallization of dirt. It is immediately transported from the karstic zones to the Jeffara plain. This transfer fo dissolved calcite was the origin of the resistant calcitic crust well known in the Jeffara plain. We now identified the same crust in a karstic depression in the Matmata Mountains, opening the way to new geomorphologic and tectonic interpretations, and a review of the eolian silts formerly attributed to the Upper Pleistocene. Later, during Upper Pliocene-Gelasian, we observe a general tectonic uplift of the Dahar chain and the Matmata Mountains as well as the subsidence of the Jeffara plain at the Medenine fault (NW-SE), prolonging the large Gafsa fault towards the East. The karstic paleoforms were thus uplifted more than 500 m, but nevertheless remain open on the Jeffara plain, as seen by large depressions. As a consequence, the karstic depressions of Matmata played the role of traps for eolian silts blown from the Jeffara plain during the extreme desertification in the Upper Pliocene-Gelasian. The morphological reconstruction since the Messinian shows a succession of important events during the Pliocene that profoundly influenced the Quaternary. All indications permit to reject the hypothesis that the Matmata silts came from the West (Eastern Erg).

 


OBSERVATIONS OF PLIOCENE KARSTS FOSSILIZED BY QUATERNARY EOLIAN SILTS IN THE MATMATA MOUNTAINS (SOUTH-EAST TUNISIA), 2012, Sghari, Abdeljalil

The submeridional Dahar chain in southeastern Tunisia is over 200 km long. It is separated from the Mediterranean Sea by the Jeffara plain with some tens of kilometers in width. This landscape continues to the South into Libya, but to the North, the chain ends with the Matmata mountains which form a plateau slightly inclined to the west and some 10 km wide. The eastern scarp shows a mainly calcareous geological stratigraphy from Upper Permian to the Senonian. The Dahar-Matmata structure belongs to the Sahara platform and shows a hiatus during the whole Tertiary, since it was emerged since Upper Cretaceous. The Tunisian Atlas nearby shows a completely different paleogeographic evolution, with a complete Tertiary series and a later Plio-Quaternary structuration. These two paleogeographic domains of Southern Tunisia, the Sahara Atlas and the NE border of the Sahara platform, were influenced by the Messinian crisis (5.9 Ma to 5.3 Ma). This was expressed by the collapse of the Mediterranean Sea level, profoundly modifying the fluvial dynamics with an inversion of the erosional system, from normal erosion to regressive erosion. It results a deepening of canyons in the downstream part and a deepening of the watercourses in the upstream part. The geological structures in the Messinian have been deeply affected by these large eustatic changes, with an incision of cluses in the Atlas and the deposition of a thick clayeysandy series that we could recently link to deltaic systems and Gilbert deltas. The re-establishment of seaways between the Atlantic and the Mediterranean, and the subsequent infill in the Lower Pliocene (Zanclean transgression), with an important inpact in Southern Tunisia, had multiple consequences in that region. The newly adjusted sealevel, together with a more humid climate that was confirmed by faunal and floral extension oof tropical plants in Northern Africa, stimulated an important karstification of the limestone areas. In the Dahar chain, caves, dolines, karstic depressions or karstic dry valleys emerged, the most spectacular ones being found in the Matmata Mountains. The karstic depressions are the forms that represent best this Pliocene karstification that surely was interrupted in an early stage, because localized endokarstic forms had not enough time to develop. So the karstification seems to have been active in Matmata from 5.4 to 4.0 million years, i.e. two times as long than the duration of the Messinian crisis. The interruption of karstification is due to an increase in temperature and dryness, which even gets more intense during the Pliocene, pulverizing the soils. Already at the beginning of the desertification, a calcareous crust forms by rapid cristallization of dirt. It is immediately transported from the karstic zones to the Jeffara plain. This transfer fo dissolved calcite was the origin of the resistant calcitic crust well known in the Jeffara plain. We now identified the same crust in a karstic depression in the Matmata Mountains, opening the way to new geomorphologic and tectonic interpretations, and a review of the eolian silts formerly attributed to the Upper Pleistocene. Later, during Upper Pliocene-Gelasian, we observe a general tectonic uplift of the Dahar chain and the Matmata Mountains as well as the subsidence of the Jeffara plain at the Medenine fault (NW-SE), prolonging the large Gafsa fault towards the East. The karstic paleoforms were thus uplifted more than 500 m, but nevertheless remain open on the Jeffara plain, as seen by large depressions. As a consequence, the karstic depressions of Matmata played the role of traps for eolian silts blown from the Jeffara plain during the extreme desertification in the Upper Pliocene-Gelasian. The morphological reconstruction since the Messinian shows a succession of important events during the Pliocene that profoundly influenced the Quaternary. All indications permit to reject the hypothesis that the Matmata silts came from the West (Eastern Erg).


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