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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. ...

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. ...

Speleology in Kazakhstan

Shakalov on 11 Jul, 2012
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. ...

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That evaporation is the changing or water from the liquid or solid states into the gaseous state through heat exchange [16].?

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Featured articles from Cave & Karst Science Journals
Chemistry and Karst, White, William B.
Engineering challenges in Karst, Stevanović, Zoran; Milanović, Petar
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Geochemical and mineralogical fingerprints to distinguish the exploited ferruginous mineralisations of Grotta della Monaca (Calabria, Italy), Dimuccio, L.A.; Rodrigues, N.; Larocca, F.; Pratas, J.; Amado, A.M.; Batista de Carvalho, L.A.
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
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Your search for shallow marine (Keyword) returned 18 results for the whole karstbase:
Showing 1 to 15 of 18
Shallow-marine carbonate facies and facies models, 1985, Tucker M. E. ,
Shallow-marine carbonate sediments occur in three settings: platforms, shelves and ramps. The facies patterns and sequences in these settings are distinctive. However, one type of setting can develop into another through sedimentational or tectonic processes and, in the geologic record, intermediate cases are common. Five major depositional mechanisms affect carbonate sediments, giving predictable facies sequences: (1) tidal flat progradation, (2) shelf-marginal reef progradation, (3) vertical accretion of subtidal carbonates, (4) migration of carbonate sand bodies and (5) resedimentation processes, especially shoreface sands to deeper subtidal environments by storms and off-shelf transport by slumps, debris flows and turbidity currents. Carbonate platforms are regionally extensive environments of shallow subtidal and intertidal sedimentation. Storms are the most important source of energy, moving sediment on to shoreline tidal flats, reworking shoreface sands and transporting them into areas of deeper water. Progradation of tidal flats, producing shallowing upward sequences is the dominant depositional process on platforms. Two basic types of tidal flat are distinguished: an active type, typical of shorelines of low sediment production rates and high meteorologic tidal range, characterized by tidal channels which rework the flats producing grainstone lenses and beds and shell lags, and prominent storm layers; and a passive type in areas of lower meteorologic tidal range and higher sediment production rates, characterized by an absence of channel deposits, much fenestral and cryptalgal peloidal micrite, few storm layers and possibly extensive mixing-zone dolomite. Fluctuations in sea-level strongly affect platform sedimentation. Shelves are relatively narrow depositional environments, characterized by a distinct break of slope at the shelf margin. Reefs and carbonate sand bodies typify the turbulent shelf margin and give way to a shelf lagoon, bordered by tidal flats and/or a beach-barrier system along the shoreline. Marginal reef complexes show a fore-reef--reef core--back reef facies arrangement, where there were organisms capable of producing a solid framework. There have been seven such phases through the Phanerozoic. Reef mounds, equivalent to modern patch reefs, are very variable in faunal composition, size and shape. They occur at shelf margins, but also within shelf lagoons and on platforms and ramps. Four stages of development can be distinguished, from little-solid reef with much skeletal debris through to an evolved reef-lagoon-debris halo system. Shelf-marginal carbonate sand bodies consist of skeletal and oolite grainstones. Windward, leeward and tide-dominated shelf margins have different types of carbonate sand body, giving distinctive facies models. Ramps slope gently from intertidal to basinal depths, with no major change in gradient. Nearshore, inner ramp carbonate sands of beach-barrier-tidal delta complexes and subtidal shoals give way to muddy sands and sandy muds of the outer ramp. The major depositional processes are seaward progradation of the inner sand belt and storm transport of shoreface sand out to the deep ramp. Most shallow-marine carbonate facies are represented throughout the geologic record. However, variations do occur and these are most clearly seen in shelf-margin facies, through the evolutionary pattern of frame-building organisms causing the erratic development of barrier reef complexes. There have been significant variations in the mineralogy of carbonate skeletons, ooids and syn-sedimentary cements through time, reflecting fluctuations in seawater chemistry, but the effect of these is largely in terms of diagenesis rather than facies

A MIDDLE PROTEROZOIC PALEOKARST UNCONFORMITY AND ASSOCIATED SEDIMENTARY-ROCKS, ELU BASIN, NORTHWEST CANADA, 1991, Pelechaty S. M. , James N. P. , Kerans C. , Grotzinger J. P. ,
A major palaeokarst erosion surface is developed within the middle Proterozoic Elu Basin, northwestern Canada. This palaeokarst is named the sub-Kanuyak unconformity and truncates the Parry Bay Formation, a sequence of shallow-marine dolostones that were deposited within a north-facing carbonate platform under a semi-arid climate. The sub-Kanuyak unconformity exhibits up to 90 m of local relief, and also formed under semi-arid conditions when Parry Bay dolostones were subaerially exposed during a relative sea-level drop of about 180 m. Caves and various karren developed within the meteoric vadose and phreatic zones. Their geometry, size and orientation were largely controlled by northwest- and northeast-trending antecedent joints, bedding, and lithology. Near-surface caves later collapsed forming valleys, and intervening towers or walls, and plains. Minor terra rossa formed on top of highs. Karstification was most pronounced in southern parts of Bathurst Inlet but decreased northward, probably reflecting varying lengths of exposure time along a north-dipping slope. The Kanuyak Formation is up to 65 m thick, and partially covers the underlying palaeokarst. It consists of six lithofacies: (i) breccia formed during collapse of caves, as reworked collapse breccia and regolith; (ii) conglomerate representing gravel-dominated braided-fluvial deposits; (iii) sandstone deposited as braided-fluvial and storm-dominated lacustrine deposits; (iv) interbedded sandstone, siltstone and mudstone of sheet flood origin; (v) dolostones formed from dolocretes and quiet-water lacustrine deposits; and (vi) red-beds representing intertidal-marine mudflat deposits. Rivers flowed toward the northwest and northeast within karst valleys and caves; lakes were also situated within valleys; marine mudflat sediments completely cover the palaeokarst to the north. A regional correlation of the sub-Kanuyak unconformity with the intra-Greenhorn Lakes disconformity within the Coppermine homocline suggests that similar styles of karstification occurred over an extensive region. The Elu Basin palaeokarst, however, was developed more landward, and was exposed for a longer period of time than the Coppermine homocline palaeokarst

THE EARLY PROTEROZOIC MISSISSIPPI VALLEY-TYPE PB-ZN-F DEPOSITS OF THE CAMPBELLRAND AND MALMANI SUBGROUPS, SOUTH-AFRICA - A REVIEW, 1995, Martini J. E. J. , Eriksson P. G. , Snyman C. P. ,
Pb-Zn-F deposits occur in the very late Archaean (2.55 Ga) shallow marine dolostone of the relatively undeformed Campbellrand and Malmani Sub-groups, which are overlain unconformably by the lower Proterozoic Postmasburg and Pretoria Group siliciclastics. They consist of stratiform deposits formed by replacement and porosity-filling, as well as pipes, ring-shaped and irregular bodies associated with collapse breccia. In the Transvaal basin the latter were generated during the karst denudation period between the deposition of the Chuniespoort Group (ending at similar to 2.4 Ga) and of the Pretoria Group (starting at 2.35 Ga). A part of these mineralisations were overprinted by the metamorphism of the Bushveld Complex intrusion at 2.06 Ga. In the Transvaal basin, the age of the mineralisation is constrained between the start of the Pretoria Group deposition and the Bushveld intrusion. It is concluded that, although most of the mineralisations are characteristic of the Mississippi Valley-type, some of the northernmost occurrences, rich in siderite, are less typical. A classic genetic model is proposed. In an environment characterised by tensional tectonics and basin development, brines of basinal origin were heated by circulation into pre-Chuniespoort rocks, leached metals from the rocks they permeated, and rose as hydrothermal plumes. At relatively shallow depth they deposited minerals after mixing with water of surficial origin

GEOLOGY AND ORE GENESIS OF THE MANGANESE ORE-DEPOSITS OF THE POSTMASBURG MANGANESE-FIELD, SOUTH-AFRICA, 1995, Vonplehweleisen E. , Klemm D. D. ,
The Postmasburg Mn/Fe-ores occur exclusively in dolomitic Precambrian sinkhole structures with siliceous breccias and shales as hostrocks. The main manganese minerals are braunite and bixbyite, apart from secondary alteration products of the psilomelane-manganomelane family. Various generations of ore minerals could be identified. The ore mineralization is subdivided into three different genetic types. They are classified either as pure karst deposits or as combined formations of karst origin and shallow marine sedimentation due to the transgression of the Banded Iron Formation (BIF) sea. Post-sedimentary metamorphism is identified as very low grade. The development of the different ore types is illustrated schematically

Karst development in the Bahamas and Bermuda, 1995, Mylroie J. E. , Carew J. L. , Vacher H. L.

Isolated carbonate platform of Caniego, Spain: A test of the latest Albian worldwide sea-level changes, 1997, Fernandezmendiola Pa, Garciamondejar J,
The upper Albian Caniego carbonate platform consists of a 20-m-thick unit of rudist- and coral-bearing limestones that crops out at the northern margin of the Mena diapir in northern Spain, The limestones were deposited on top of a slowly subsiding area, the Mena paleohigh, a diapiric-induced horst bounded by synsedimentary faults, The Caniego limestones originated in shallow warm tropical waters following a widespread marine transgression at the base of the foraminifera Rotalipora appenninica zone (ammonite Stoliczkaia dispar zone), Around the middle part of the appenninica zone the Caniego limestones underwent subaerial exposure and karst development, Fibrous calcite cements filled the bulk of the fissure-dike and dissolution cavities, Field, petrological, and geochemical data indicate that the fibrous calcites are meteoric flowstones, delta(18)O values in these cements range from -3 parts per thousand to -4.5 parts per thousand and delta(13)C values range from -7 parts per thousand to -14 parts per thousand (relative to the Peedee belemnite [PDB] standard), Thick wedges of nearshore shallow-marine siliciclastic sediments were deposited in paleotrough areas surrounding the Caniego paleohigh while the platform was subaerially exposed, The carbonate platform was drowned in early Cenomanian time and hardground-condensed facies developed during this period (Rotalipora brotzeni zone), Deeper water noncondensed marry sedimentation was reestablished in the mid-Cenomanian (Rotalipora reicheli zone), Comparison of the Iberian Caniego limestones with worldwide successions suggests a coincidence in the timing of platform formation emergence and drowning in several basins of different lithospheric plates, Nevertheless, an overall lack of coordination of sea-level histories from different basins may be related to tectonic movements of the lithospheric plates, Plate rearrangement is invoked as the primary control on relative sea-level changes and sequence development

An overview of the geology of the Transvaal Supergroup dolomites (South Africa), 1998, Eriksson Pg, Altermann W,
In the Neoarchaean intracratonic basin of the Kaapvaal craton, between approximately 2640 Ma and 2516 Ma, two successive stromatolitic carbonate platforms developed. Deposition started with the Schmidtsdrif Subgroup, which is probably oldest in the southwestern part of the basin, and which contains stromatolitic carbonates, siliciclastic sediments and minor lava flows. Subsequently, the Nauga formation carbonates were deposited on peritidal flats located to the southwest and were drowned during a transgression of the Transvaal Supergroup epeiric sea, around 2550 Ma ago. This transgression led to the development of a carbonate platform in the areas of the preserved Transvaal and Griqualand West basins, which persisted for 30-50 Ma. During this time, shales were deposited over the Nauga Formation carbonates in the south-western portion of the epeiric sea. S subsequent period of basin subsidence led to drowning of the stromatolitic platform and to sedimentation of chemical, iron-rich silica precipitates of the banded iron formations (BIF) over the entire basin. Carbonate precipitation in the Archaean was largely due to chemical and lesser biogenic processes, with stromatolites and ocean water composition playing an important role. The stromatolitic carbonates in the preserved Griqualand West and Transvaal basins are subdivided into several formations, based on the depositional facies, reflected by stromatolite morphology, and on a intraformational unconformities; interbedded tuffs and available radiometric age data do not ye permit detailed correlation of units from the two basins. Thorough dolomitisation of most formations took place at different post-depositional stages, but mainly during early diagenesis. Partial silification was the result of diagenetic and weathering processes. Karstification of the carbonate rocks was related to periods of exposure to subaerial conditions and to percolation of groundwater. Such periods occurred locally at the time of carbonate and BIF deposition. Main karstification, however, probably took place during an erosional period between approximately 2430 Ma and 2320 Ma

The role of high-energy events (hurricanes and/or tsunamis) in the sedimentation, diagenesis and karst initiation of tropical shallow water carbonate platforms and atolls, 1998, Jan F. G. B. L. ,
Karst morphology appears early, even during carbonate sediment deposition. Examples from modern to 125-ka-old sub-, inter- and supratidal sediments are given from the Bahamas (Atlantic Ocean) and from Tuamotuan atolls (southeastern Pacific Ocean), with mineralogical and hydrological analyses. Karstification is favoured by the aragonitic composition of bioclasts coming from the shallow marine bio-factory. Lithification by aragonite cements appears as a rim around carbonate deposits and dissolution and non-cementation start at the same time on modern supratidal deposits (Andros micrite or atoll coral rudite) and provoke the formation of a central depression on small or large carbonate platforms. In fact, this early solution of the centre of platforms is closely related to the location of each of the studied examples on hurricane tracks. High-energy events, such as hurricanes and tsunamis, affect sediment transport but hurricanes also affect diagenesis as a result of the enormous volume of freshwater carried and discharged along their paths. This couple, lithification- solution, is localised at sea level and accompanies sea-level fluctuations along the eustatic curve. Because of the precise location of hurricane action all around the Earth, early karstification by aragonite solution, cementation and supratidal carbonate sediment accumulations thigh-energy trails) act together on all the platforms and atolls located inside the Tropics (23 degrees 27') between roughly 5 degrees-10 degrees and 25 degrees on both hemispheres. However, early karstification acts alone on shallow carbonate platforms including atolls along the equatorial belt between 5 degrees-10 degrees N and 5 degrees-10 degrees S. These early steps of karstification are linked to the ocean-atmosphere interface due to the bathymetrical position of shallow carbonate platforms, including atolls. They lead to complex karstified emerged platforms, called high carbonate islands, where carbonate diagenesis, together with the development of bauxite- and/or a phosphate-rich cover and phreatic lens, will occur. (C) 1998 Elsevier Science B.V. All rights reserved

A record of multistage continental break-up on the Brianconnais marginal plateau (Western Alps): Early and Middle-Late Jurassic rifting, 1999, Claudel Me, Dumont T,
The Brianconnais series in the French Western Alps near Briancon bear evidence of extensional deformation preceding Alpine shortening. Most of these structures have been ascribed to Tethyan rifting processes. However, many of them are younger than the initial opening of the Ligurian Tethys ocean (Late Bajocian-Early Bathonian) and have a different orientation than the syn-rift faults. The combined use of sedimentological, stratigraphic, paleostructural and structural methods allows to distinguish the features related to the Tethyan rifting (Early to early Middle Jurassic) from the younger extensional deformation (Late Jurassic) which in part overprinted them: The Tethyan rifting is marked by a subaerial erosional surface (breakup unconformity), bearing karsts which developed along syn-rift faults. The continental to shallow marine diagenetic inprints are analysed (diagenetic log method). The Tethyan syn-rift uplift occurred as pulses from the early Late Triassic (Champcella type units) to the late Early Liassic (Peyre-Haute unit), whereas Tethyan post-rift drowning was synchronous (Late Bathonian thermal subsidence). We propose that the post-break-up extensional deformation (Late Jurassic) is linked with intracontinental rifting of the Atlantic realm (Bay of Biscay and/or Valais rifts). Therefore, the pre-Alpine deformations recorded in the Brianconnais series may result from the interference between different Mesozoic rifting-spreading cycles. Alpine inversion processes are more complex than previously thought since (1) the pre-Alpine structural grain was made of at least two, nearly perpendicular trends, (2) convergence changed in orientation through time, making it possible to reactivate preferentially either one or the other trend, and (3) significant nappe rotations are expected, which may be considered for palinspastic restoration. This has important paleogeographic implications, i.e. the present-day upper units of the Brianconnais pile are not necessarily derived from more distal parts of the Tethyan margin than the lower ones since they may have suffered important lateral, possibly northward, transport before final outward stacking

Dolomitization of Holocene Shallow-Marine Deposits Mediated by Sulfate Reduction and Methanogenesis in Normal-Salinity Seawater, Northern Belize, 2000, Teal Chellie S. , Mazzullo S. J. , Bischoff William D. ,
Dolomite constitutes an average of 12% of the Holocene organic-rich sediments over a 15 km2 area of the Cangrejo Shoals mudbank in northern Belize. Although it defines a laterally persistent stratiform body that averages 3 m thick, it is present throughout the 7.6-m-thick sediment section. These transgressive sediments are less than [~]6400 years old and were deposited in shallow-marine environments of normal salinity. The dolomite is dominantly cement, and average crystal size is 7 m. There are no significant correlations among amount of dolomite vs. sediment texture, mineralogy, porosity, or mole % MgCO3 in associated particulate high-Mg calcite, depth, or location on the shoals. The dolomites are poorly ordered and calcic (39.5-44.5 mole % MgCO3), with low mean Mn (210 ppm) and relatively high mean Sr (1034 ppm) concentrations. There is no evidence of recrystallization or geochemical alteration of the dolomite. {delta}18O values of the dolomites range from 0.5 to 2.8{per thousand}PDB, and the mean value (2.1{per thousand}) suggests that the dolomite precipitated from normal-salinity pore water. Dolomite {delta}13C values range from -5.2{per thousand} to .6{per thousand}PDB (mean seawater {delta}13C = 0.5{per thousand}), which suggests dolomitization promoted by both bacterial sulfate reduction and methanogenesis in environments with anoxic pore water. Dolomitization attending these organodiagenetic reactions apparently was reversible over time, and episodic rather than continual precipitation is indicated. Requisite Mg and Ca were provided by seawater and by some dissolution of host sediments. The most rapid period of dolomitization may have been during early transgression, when relatively high sedimentation rates sustained high levels of organodiagenesis and pore-water alkalinities

Palaeo-coastal morphology of the neoproterozoic Badami basin - Some field evidences from Khanapur, Bagalkot district, Karnataka, 2002, Dey S, Rao Rg, Kumar S, Veerabhaskar D,
The Neoproterozoic Badami Group of the Kaladgi-Badami basin consists of an undisturbed sequence of sandstone, shale and limestone exposed in the northern districts of Karnataka and adjoining parts of Maharashtra (Viswanathiah, 1977; Jayaprakash et al. 1987). The sequence unconformably overlies Archaean granitoids, schists and the Mesoproterozoic Bagalkot Group of sediments. The environment of deposition of the Badami Group has been interpreted as shallow marine (Sathyanarayan, 1994). This note presents some field evidences around Khanapur village, Bagalkot district revealing the nature of palaeo-coastal morphology during the deposition of Cave Temple arenite (CTa), the main sandstone member of the Badami Group

The Barremian-Aptian Evolution of The Eastern Arabian Carbonate Platform Margin (Northern Oman), 2003, Hillgartner Heiko, Van Buchem Frans S. P. , Gaumet Fabrice, Razin Philippe, Pittet Bernard, Grotsch Jurgen, Droste Henk,
Carbonate platform margins are sensitive recorders of changes in sea level and climate and can reveal the relative importance of global and regional controls on platform evolution. This paper focuses on the Barremian to Aptian interval (mid Cretaceous), which is known for climatic and environmental changes towards more intensified greenhouse conditions. The study area in the northern Oman mountains offers one of the very few locations where the Cretaceous carbonate margin of the Arabian Plate can be studied along continuous outcrops. Our detailed sedimentological and sequence stratigraphic model of the platform margin demonstrates how major environmental and ecological changes controlled the stratigraphic architecture. The Early Cretaceous platform margin shows high rates of progradation in Berriasian to Hauterivian times followed by lower rates and some aggradation in the Late Hauterivian to Barremian. High-energy bioclastic and oolitic sands were the dominant deposits at the margin. Turbidites were deposited at the slope and in the basin. The Early Aptian platform margin shows a marked change to purely aggradational geometries and a welldeveloped platform barrier that was formed mainly by microbial buildups. The sudden dominance in microbial activity led to cementation and stabilization of the margin and slope and, therefore, a decrease of downslope sediment transport by turbidites. In the Late Aptian, large parts of the Arabian craton were subaerially exposed and a fringing carbonate platform formed. Seven Barremian to Early Albian large-scale depositional sequences reflecting relative sea-level changes are identified on the basis of time lines constrained by physical correlation and biostratigraphy. The reconstruction of the margin geometries suggests that tectonic activity played an important role in the Early Aptian. This was most likely related to global plate reorganization that was accompanied by increased volcanic activity in many parts of the world. Along the northeastern Arabian platform the associated global changes in atmospheric and oceanic circulation are recorded with a change in platform-margin ecology from an ooid-bioclast dominated to a microbial dominated margin. Time-equivalent argillaceous deposits suggest an increase in rainfall and elevated input of nutrients onto the platform. This process contributed to the strongly diminished carbonate production by other organisms and favored microbial activity. The platform margin may thus represent a shallow-marine response to the Early Aptian global changes, commonly associated with an oceanic anoxic event in basinal environments

Unraveling the Origin of Carbonate Platform Cyclothems in the Upper Triassic Durrenstein Formation (Dolomites, Italy), 2003, Preto Nereo, Hinnov Linda A. ,
Facies analysis of the Durrenstein Formation, central-eastern Dolomites, northern Italy, indicates that this unit was deposited on a carbonate ramp, as evidenced by the lack of a shelf break, slope facies, or a reef margin, together with the occurrence of a 'molechfor' biological association. Its deposition following the accumulation of rimmed carbonate platforms during the Ladinian and Early Carnian marks a major shift in growth mode of the Triassic shallow marine carbonates in the Dolomites. The Durrenstein Formation is characterized by a hierarchical cyclicity, with elements strongly suggestive of an allocyclic origin, including (a) subaerial exposure features directly above subtidal facies within meter-scale cyclothems, (b) purely subtidal carbonate cyclothems, (c) symmetric peritidal carbonate cyclothems, and (d) continuity of cyclothems of different orders through facies boundaries. The Durrenstein cyclothems are usually defined by transgressive and regressive successions, and so most of them probably originated from sea-level oscillations. Their allocyclic origin allows their use for high-resolution correlations over distances up to 30 km. A stratigraphic section in the Tre Cime di Lavaredo area, encompassing the upper part of the Durrenstein Formation and the lower part of the overlying Raibl Formation (Upper Carnian) was studied using time-frequency analysis. A strong Milankovitch signal appeared when interference arising from a variable sedimentation rate was estimated and removed by tuning the short precession line in a spectrogram. All of the principal periodicities related to the precession index and eccentricity, calculated for 220 Ma, are present: P1 (21.9 ky); P2 (17.8 ky); E1 (400 ky), E2 (95 ky), and E3 (125 ky), along with a peak at a frequency double that of the precession, which is a predicted feature of orbitally forced insolation at the equator. Components possibly related to Earth's obliquity at ca. 35 ky and ca. 46 ky are present as well. The recovery of Milankovitch periodicities allows reconstruction of a high-resolution timescale that is in good agreement with published durations of the Carnian based on radiometric ages. The recognition of a Milankovitch signal in the Durrenstein and lower Raibl formations, as well as in other Mesozoic carbonate platforms, strongly supports a deterministic and predictable--rather than stochastic--control on the formation of carbonate platforms. Carbonate platforms might thus be used in the future for the construction of an astronomical time scale for the Mesozoic

Patterns and controls of surface sediment distribution: west-central Florida inner shelf, 2003, Brooks Gr, Doyle Lj, Davis Ra, Dewitt Nt, Suthard Bc,
The west-central Florida inner shelf represents a transition between the quartz-dominated barrier-island system and the carbonate-dominated mid-outer shelf. Surface sediments exhibit a complex distribution pattern that can be attributed to multiple sediment sources and the ineffectiveness of physical processes for large-scale sediment redistribution. The west Florida shelf is the submerged extension of the Florida carbonate platform, consisting of a limestone karst surface veneered with a thin unconsolidated sediment cover. A total of 498 surface sediment samples were collected on the inner shelf and analyzed for texture and composition. Results show that sediment consists of a combination of fine quartz sand and coarse, biogenic carbonate sand and gravel, with variable but subordinate amounts of black, phosphorite-rich sand. The carbonate component consists primarily of molluskan fragments. The distribution is patchy and discontinuous with no discernible pattern, and the transition between sediment types is generally abrupt. Quartz-rich sediment dominates the inner 15 km north of the entrance into Tampa Bay, but south of the Bay is common only along the inner 3 km. Elsewhere, carbonate-rich sediment is the predominate sediment type, except where there is little sediment cover, in which cases black, phosphorite-rich sand dominates. Sediment sources are likely within, or around the periphery of the basin. Fine quartz sand is likely reworked from coastal units deposited during Pleistocene sea-level high stands. Carbonate sand and gravel is produced by marine organisms within the depositional basin. The black, phosphorite-rich sand likely originates from the bioerosion and reworking of the underlying strata that irregularly crop out within the study area. The distribution pattern contains elements of both storm- and tide-dominated siliciclastic shelves, but it is dictated primarily by the sediment source, similar to some carbonate systems. Other systems with similar sediment attributes include cool-water carbonate, sediment-starved, and mixed carbonate/siliciclastic systems. This study suggests a possible genetic link among the three systems. (C) 2003 Elsevier B.V. All rights reserved

Evolution of the Adriatic carbonate platform: Palaeogeography, main events and depositional dynamics, 2005, Vlahovic I. , Tisljar J. , Velic I. , Maticec D. ,
The Adriatic Carbonate Platform (AdCP) is one of the largest Mesozoic carbonate platforms of the Perimediterranean region. Its deposits comprise a major part of the entire carbonate succession of the Croatian Karst (External or Outer) Dinarides, which is very thick (in places more than 8000 m), and ranges in age from the Middle Permian (or even Upper Carboniferous) to the Eocene. However, only deposits ranging from the top of the Lower Jurassic (Toarcian) to the top of the Cretaceous can be attributed to the AdCP (defined as an isolated palaeogeographical entity). Although the entire carbonate succession of the Karst Dinarides was deposited within carbonate platform environments, there were different types of carbonate platforms located in different palaeogeographical settings. Carboniferous to Middle Triassic mixed siliciclastic-carbonate deposits were accumulated along the Gondwanian margin, on a spacious epeiric carbonate platform. After tectonic activity, culminating by regional Middle Triassic volcanism recorded throughout Adria (the African promontory), a huge isolated carbonate Southern Tethyan Megaplatform (abbreviated as STM) was formed, with the area of the future AdCP located in its inner part. Tectonic disintegration of the Megaplatform during the middle to late Early Jurassic resulted in the establishment of several carbonate platforms (including the Adriatic, Apenninic and Apulian) separated by newly drowned deeper marine areas (including the Adriatic Basin as a connection between the Ionian and Belluno basins, Lagonero, Basin, and the area of the Slovenian and Bosnian troughs). The AdCP was characterised by predominantly shallow-marine deposition, although short or long periods of emergence were numerous, as a consequence of the interaction of synsedimentary tectonics and eustatic changes. Also, several events of temporary platform drowning were recorded, especially in the Late Cretaceous, when synsedimentary tectonics became stronger, leading up to the final disintegration of the AdCP. The thickness of deposits formed during the 125 My of the AdCP's existence is variable (between 3500 and 5000 m). The end of AdCP deposition was marked by regional emergence between the Cretaceous and the Palaeogene. Deposition during the Palaeogene was mainly controlled by intense synsedimentary tectonic deformation of the former platform area-some carbonates (mostly Eocene in age) were deposited on irregular ramp type carbonate platforms surrounding newly formed flysch basins, and the final uplift of the Dinarides reached its maximum in the Oligocene/Miocene. The Adriatic Carbonate Platform represents a part (although a relatively large and well-preserved one) of the broader shallow-water carbonate platform that extended from NE Italy to Turkey (although its continuity is somewhat debatable in the area near Albanian/Greece boundary). This large carbonate body, which was deformed mostly in the Cenozoic (including a significant reduction of its width), needs a specific name, and the Central Mediterranean Carbonate Platform is proposed (abbreviated to CMCP), although the local names (such as AdCP for its NW part) should be kept to enable easier communication, and to facilitate description of local differences in platform evolution,

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