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This paper re-evaluates the karst phenomenon in Turkey basing on the controlling factors such as, the source of energy gradient, lithostratigraphy, type of erosion base and climate. Two major karst types described are a) evolutionary karst which implies continuous karstification but at different stage of maturation and b)rejuvenated karst which is formed by reactivating a formerly developed and subsequently ceased karst structure either by an uplift and/or a drastic decline of erosion base. Description of karst types considering both morphology and hydrogeology revealed that distribution of specific karst types is compatible with the neotectonic evolution of Turkey. Karst in all provinces except the Black Sea and Western Anatolian regions, is developed under the effect of the energy gradient provided by uplift. Different rates of uplift created different sub-types of karst. The climate effect was evaluated as a secondary factor for it has a role of shaping/re-shaping the karst forms rather than controlling the physical and chemical processes.
The aim of this study is to show tectonic features in selected poljes and minor basins in the Dinaric Karst. Boreholes and gravimetric measurements show thick Neogene loose sediments and the rocky bottom below the sea level - real cryptodepressions. The sediments make parts of a large plain that subsided at the end of the low Pliocene. The recent seismic activity in this area proves the ongoing tectonic process. The deepest (more than 100 m) and the smallest polje in the Slovenian Dinaric karst, Globodol is a dry polje in the piezometric level. Quaternary subsidence of the bottom is the only reasonable explanation of its genesis. On Planinsko polje there are signs ob suballuvial corrosion and the indicators of the Holocene tectonic subsidence. Four poljes in the Ravni kotari (Dalmatia) are shallow basins in the first stage of development. They prove the process of the bottom levelling below the shallow cover of alluvial sediments. An extremely deep small basin is about 450 m deep Red Lake (Hercegovina) and small basins at Črnomelj and Kočevje (Slovenia), 300 m and 100 m deep below the sea level.
The canyon valley of the Rakitnica river is one of the deepest and longest in the Dinaric karst. The paper states the basic morphological and morphostructural characteristics of the canyon, and gives its geomorphological regionalization. High level of correlation between lithology, tectonics and relief of the researched area has been determined. Genesis and development of this relief form have been considerably guided by neotectonic processes during the Quaternary.
Deep inside the Frasassi cave complex in the foreland fold and thrust belt of the northeastern Apennines (central Italy), the remains of hundreds of eels (Anguilla anguilla) are found scattered on the shores of phreatic lakes up to 5 m above the water table. These sub-fossil eels, and the speleothemic calcite encrusting some of them, offer the rare opportunity for radiocarbon dating leading to a geochronologic scale for the shorelines, which record the lowering of the water table and the uplifting of the Frasassi area through the Holocene. The lakes' margins are contoured by white microcrystalline calcite rinds, which also record the progressive lowering of the water table. Detailed surveying revealed that these rinds are no longer horizontal, but slightly tilted toward ENE. Thus these rinds record a recent history not only of uplifting, but also of tectonic tilting of this region. The results of our analyses indicate that the Apennine area around Frasassi has been rising, for the past 8000 years, at a mean rate of 0.6 mm/yr, which is consistent with uplifting rates estimated from the step topography arrangement of interglacial fluvial terraces for the whole Quaternary period in this region. This work demonstrates how an interdisciplinary approach to speleologic research can provide a significant contribution to active tectonic studies.
The formation of karst caves in Caledonide metamorphic limestones in a repeatedly-glaciated 40000km2 region in central Scandinavia was initiated by tectonic inception, a process in which open fracture routes, primarily created by deglacial seismicity, provided the opportunity for subsequent dissolution and enlargement into cave passages in both deglacial and interglacial environments. The tectonic inception model built on reports of a ‘partially detached’ thin upper crustal layer in similar settings in Scotland and this paper shows that the present maximum subsurface cave distance (i.e. the distance of a passage to the nearest land surface) is commonly less than one-eighth of the depth of the local glaciated valley. This suggests that fracture generation was related to the scale of isostatic uplift and was partly determined by the magnitude of seismicity caused by the differential pressure change and differential uplift that occurred along valley walls as the ice margin of each of the major Pleistocene icesheets receded from west to east. The maximum one-eighth relationship is also commonly maintained in other Caledonide marble terranes in Scandinavia, Scotland and New England (USA), suggesting that many of the caves in these areas were formed by similar processes.
Large-scale crustal subsidence proposed for the New Madrid region (Forte et al., 2007) can explain the upwelling of saline groundwater in the Northern Mississippi Embayment and parts of the adjacent Ozarks. As rock moves downward, deep groundwater is displaced upward. Raising the Ozarks relative to the Mississippi Embayment increases hydraulic pressure in sandstone aquifers and stresses the interlayered, low-conductivity, telogenetic, carbonates. In response to the increased pressure, groundwater finds new pathways to exit freshwater confined aquifers. Upward cross-formational discharge of deep groundwater can produce cave passages that do not correlate with joints as well as huge spring flows that do not correlate with catchment areas. Recognition of the widespread regional discharge regime in the Ozark region has been hampered by the unfounded assumption of unconfined conditions based on water levels from wells open to large intervals. Recent studies, using techniques such as flow meters, reveal relatively thin, pressurized sandstones at surprisingly high elevations in areas that were once thought to be recharge zones. The pressurized aquifers limit downward infiltration of meteoric recharge and create a complex flow field: a topography-driven meteoric regime perched above an overpressured regime driven by neotectonics. The boundary between the two competing regimes shifts continuously as valleys entrench and karstification changes the hydraulic function of carbonates. As denudation progresses, different parts of the Ozark stratigraphic column are in different karstification zones at the same time. Beneath uplands, groundwater is confined by relatively shallow unfractured carbonates. Ubiquitously ascending waters move upward into sandstone layers and then laterally toward the valleys. Mixing creates large conduits beneath sandstones and eventually unroofing opens fractures in the carbonates, allowing epigenic processes to become dominant. Wells that seal off or miss the upper pressurized sandstone can produce low water levels, a condition the USGS refers to as ‘mature karst’. In epigenic zones near deep valleys, sandstones that extend back into the uplands can continue to supply deep groundwater to perennial cave streams.
Flank margin caves (FMC) have been predominantly described on carbonate islands such as in the Bahamas or the Marianas, using the Island Karst Model. This model has been used to explain karst development on young carbonate islands with poorly cemented eolianites, which differ substantially from continental karst, formed in well cemented limestones. Karst on continental margins especially the southern Australian coast, are not in well cemented telogenic rocks but in highly porous, highly permeable marine and eolian calcarenites. The gradual uplift over the past 50 Ma of the southern edge of the continent has resulted in Flank Margin Caves which formed in a coastal setting, being positioned significantly further inland and reflect the neotectonics of the Southern Australian passive continental margin rather than solely the Pleistocene glacio/eustatic sealevel fluctuations. The inter-relationship of tectonic setting, the distinctive characteristics of FMC and the speleogenesis of coastal karst assists in the understanding of the karst landscape evolution of significant karst areas of southern Australia.
Tectonic research and morphologi calobservations were carried out in six caves (Kalacka, Goryczkowa, Kasprowa Ni¿na, Kasprowa OErednia, Kasprowa Wy¿nia and Magurska) in the Bystra Val ley, in the Tatra Moun -tains. There are three cave lev els, with the youn gest ac tive and the other two in ac tive, re flect ing de vel op ment partly un der epiphreatic and partly un der phreatic con di tions. These stud ies dem on strate strong con trol of the cave pat tern by tec tonic fea tures, in clud ing faults and re lated frac tures that orig i nated or were re ju ve nated dur ing up lift,last ing from the Late Mio cene. In a few lo cal cases, the cave pas sages are guided by the com bined in flu ence of bed ding, joints and frac tures in the hinge zone of a chev ron anticline. That these cave pas sages are guided by tec tonic struc tures, ir re spec tive of lithological dif fer ences, in di cates that these proto-con duits were formed by “tec tonic in cep tion”. Dif fer ences in the cave pat tern be tween the phreatic and epiphreatic zones at a given cave level may be a re sult of mas sif re lax ation. Be low the bot tom of the val ley, the ef fect of stress on the rock mass is re lated to the re gional stress field and only in di vid ual faults ex tend be low the bot tom of the val ley. Thus in the phreatic zone, the flow is fo cused and a sin gle con duit be comes en larged. The lo cal ex ten sion is more in tense in the epiphreatic zone above the val ley floor and more frac tures have been suf fi ciently ex tended to al low wa ter to flow. The wa ter mi grates along a net work of fis sures and a maze could be form ing. Neotectonic dis place ments (of up to 15 cm), which are more re cent than the pas sages, were also iden ti fied in the caves. Neotectonic ac tiv ity is no lon ger be lieved to have as great an im pact on cave mor phol ogy as pre vi ously was thought. Those faults with dis place ments of sev eral metres, de scribed as youn ger than the cave by other au thors, should be re clas si fied as older faults, the sur faces of which have been ex posed by speleogenesis. The pos si ble pres ence of neotectonic faults with greater dis place ments is not ex cluded, but they would have had a much greater mor pho log i cal im pact than the ob served fea tures sug gest.
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