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Simplified geological map of the Murgia overlaid on the Digital Elevation Model: (1) Meso-Cenozoic carbonate units of the Apulian Foreland with local Quaternary covers; (2) Quaternary marine (Bradanic Trough and terraces) deposits; (3) Quaternary continental deposits; (4) locations of analysed caves and shafts; (5) boundary of the study area.
Source publication
Sea level is the base level for groundwater circulation in coastal aquifers. The evolution of karst surface landforms and subsurface drainage systems in these aquifers has been conditioned in geological time by tectonics and glacio-eustatic sea-level changes. Present morpho-structural settings and the type/distribution of karst surface and subsurfa...
Contexts in source publication
Context 1
... Apulia carbonate Platform is the upper part of the Apulia Foreland sedimentary cover, emerged at the Cretaceous age, which is part of the stable and slightly deformed foreland of the South-Apennine orogenic system ( Doglioni et al., 1994;Pieri et al., 1997). It consists of a well-bedded succession of Jurassic-Cretaceous carbonate rocks of generally restricted platform or back-reef facies, from about 3 to 5 km thick ( Figure 2). ...
Context 2
... morphometric indexes were deduced by a Digital Elevation Model (DEM) with a grid resolution of 10 m elaborated from the numerical cartography at 1:5000 scale (Regione Puglia, 2008). The analysis was performed from the top of the Murgia plateau (675 m a.s.l.) downhill, on a surface limited downward by the 60 m isohypse, and, on the W and SW side, by a vertical surface that contours carbonate outcrops with no or limited covers of Quaternary soils (Figure 2). Areas at elevations lower than 60 m a.s.l. or outside the borders, under covers or confining units made up by soft rocks or loose soils, were not considered in the analysis because subject to different morphological dynamics. ...
Context 3
... the 380 fact-sheets concerning the Murgia region, only 225 contained useful data: of the 225 karst forms, 85 are vertical shafts and 140 are horizontal caves, often of multi-level type. Their location is shown in Figure 2. The remaining fact-sheets were disregarded either because they were lacking the elevation reference, or due to their obstruction that prevented the speleologists collecting the relevant information. ...
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Citations
... Associati comunemente a terre rosse provenienti dalla dissoluzione carsica e interessati da sistemi di discontinuità da fenomeni tettono-carsici. Sui versanti fronte mare sono riconosciute in continuità superfici subpianeggianti di abrasione marina, che si correlano all'interno con piane carsiche (Canora et al., 2012) • formazione delle "Calcareniti di Gravina" (Pleistocene inf.): rappresenta il termine di apertura del ciclo sedimentario di avanfossa ed è formata da biocalcareniti e biocalciruditi organogene e massive a grana grossa, giallo-verdastre con abbondanti resti di micro e macrofossili. Poggiano in discordanza e trasgressione sui calcari cretacici. ...
... Il livello mare è il potenziale zero di un acquifero costiero e quindi richiama il flusso continentale; se questo livello è stabile per lunghi periodi, in ambiente carsico è verificato (Canora et al., 2012) come le quote di stazionamento del livello mare abbiano condizionato lo sviluppo del carsismo sotterraneo e delle piane carsiche in superficie, oltre che terrazzamenti sui versanti esposti verso il mare. ...
... La morfologia, i sedimenti di fondo e la soglia sono congruenti con il tipo ipotizzato, che ovviamente comporta lo spostamento del primo sifonamento della falda carsica molto indietro nel tempo, con un mare ad una importante quota di stazionamento pre-tirreniana (Figg. 8 e 9) (Ricchetti,1972), corrispondente all'attuale quota di circa 70 m slm (Canora et al. 2012). Il processo erosivo nei calcari mesozoici potrebbe collegarsi o accompagnarsi a una morfologia originariamente endoreica. ...
Il paesaggio di Taranto è caratterizzato
oggi dai due specchi ellittici
del Mar Piccolo, separati dall’istmo di
Punta Penna e dal più ampio cerchio del
Mar Grande, chiuso parzialmente dalle
Isole Cheradi. Tale configurazione ha
assegnato a Taranto l’appellativo di “città
dei due mari”. Eppure, i mari di Taranto
sono stati molti di più, non meno di dieci,
anche se mai contemporaneamente,
a varie quote e in un periodo che inizia
nel tardo Pleistocene ed arriva ad oggi.
Varie sono state le interpretazioni delle
forme e delle loro origini ed evoluzioni,
raramente coinvolgenti il principale fattore
morfogenetico, l’emersione nell’area
costiera di Taranto di una potente
falda idrica. A guidare l’emersione di tale
acquifero nell’area di Taranto è stato il
colmamento della Fossa Bradanica, che
ha impermeabilizzato il bordo Ovest
del serbatoio, la Murgia carbonatica; le
variazioni del livello mare e i suoi stazionamenti
hanno invece definito volta per
volta le quote di emersione e dei processi
erosionali associati.
La moderata complessità del sistema
è quindi responsabile di un’evoluzione
geomorfologica di un ampio territorio,
che si spinge a Nord almeno fino a
Grottaglie, ed a Sud, oltre il cerchio del
Mar Grande, chiuso dalle Isole Cheradi,
ben visibile anche sotto il mare attuale,
in un intervallo temporale che va
dal post Calabriano ad oggi. Il risultato
odierno di questa lunghissima storia è
nella conformazione morfologica del
territorio sommerso ed emerso, in sorgenti
subaeree e sottomarine, in bacini
evaporanti.
... These changes can result from a combination of climatic cycles (e.g. glacial-interglacial alternation) and vertical crustal motions (e.g., Westaway, 1993;Bosi et al., 1996;Tortorici et al., 2003;Catalano et al., 2008b;Canora et al., 2012;Columbu et al., 2017;Meschis et al., 2020). The age determinations for karst processes and their related morphologies are commonly based on bio-and geochronological dating of the infilling sediments and speleothems in karst caves and conduits (White, 1988;Ford and Williams, 1989;Geyh and Schleicher, 1990;Colman and Pierce, 2000;Dumitru, 2000;Forman et al., 2000;Noller et al., 2000;Bosak, 2002;Meyer et al., 2011;Szanyi et al., 2012;Audra and Palmer, 2013;Hauselmann et al., 2015;Columbu et al., 2017;Engel et al., 2020;Dumitru et al., 2021). ...
... The age determinations for karst processes and their related morphologies are commonly based on bio-and geochronological dating of the infilling sediments and speleothems in karst caves and conduits (White, 1988;Ford and Williams, 1989;Geyh and Schleicher, 1990;Colman and Pierce, 2000;Dumitru, 2000;Forman et al., 2000;Noller et al., 2000;Bosak, 2002;Meyer et al., 2011;Szanyi et al., 2012;Audra and Palmer, 2013;Hauselmann et al., 2015;Columbu et al., 2017;Engel et al., 2020;Dumitru et al., 2021). For karst systems lacking direct geochronological constraints, alternative indirect dating methods are often based on either the correlation of karst morphologies with independently dated fluvial (Hromas, 1968;Harmand et al., 2017) or marine (e.g., Florea and Vacher, 2006;Canora et al., 2012) terraces. These indirect methods imply short distance and/or a physical continuity between the fluvial or karst forms and the coastal area, where the signals of Quaternary eustatic oscillations are morphologically expressed as marine terraces and paleo-shorelines. ...
... Thus, the analyzed karst features are considered as the product of dissolution near the base level. For this reason, for the coastal sector of the Floridia Basin, we followed the approach that Florea and Vacher (2006) and Canora et al. (2012) applied in Florida (USA) and in Apulia (southern Italy), respectively. These authors correlate the mapped paleo-karst caves with the marine terrace levels and their paleo-shorelines located at similar elevations. ...
In steady-state tectonic-climate systems, the fluvio-karst processes attain a stable base level, whether it be local or global. In contrast, in an uplifting region, relative base-level changes force river incision processes and a concurrent lowering of the karst water-table. Even at local scales (e.g., single fault-controlled valley), combined tectonically- and climatically-driven base-level drops induce geomorphic and hydrogeological disequilibrium. Thus, the karst system develops vertically and the water-table lowers trying to attain the new local base level. Conversely, the paleo-karst network dries, and becomes abandoned as a hanging relic with aligned karst morphologies. They are exhumed by the entrenchment of the fluvial network, as base-level fall related knickpoints migrate upstream. We propose a geomorphic approach to build fluvio-karst age models, based upon the analysis of river long-profiles. This approach is complementary to altimetric correlation between karst horizons and coastal paleo-sea level markers. Our approach is useful for an inland study area that is far from the marine terraced coast or where active faulting cuts off the coastal area from the inland landscape. We tested the approach in the eastern sector of the Hyblean Plateau (Sicily, Italy), where a carbonate sequence experienced Middle-Late Pleistocene tectonic uplift combined with active faulting. Specifically, we investigated the Cassibile River basin, at the footwall of the active Cassibile-Noto Fault. By reconstructing river paleo-long profiles we fixed time-space reference lines, connecting the abandoned and hanging fluvio-karst levels to the correlative marine strandlines carved along the fault-controlled coastal landscape.
... Available data from deep wells distributed in the Peninsula show that freshwater floats on saltwater of marine origin (lower hydraulic limit) with freshwater maximum thicknesses around 120 m at the wells with the highest water levels. During the geological history, under the combined effect of complex tectonics and glacio-eustatic oscillations [38], the heterogeneous carbonate formation underwent vadose, water table, and transitionzone karstification, which made evolving its secondary porosity. Such processes shaped the basement surface, forming karst plains, endorheic basins, dolines, sinkholes, and the basement subsurface, making evolving secondary porosity of main faults and associated fracture zones, and shaping sub-horizontal levels. ...
Salento is a regional coastal karst aquifer located in Southern Italy with a highly complex geological, geomorphological, and hydrogeological structure. High and unruly exploitation of groundwater from licensed and unlicensed wells for irrigation and drinking purposes affects groundwater, with consequent degradation of its qualitative and quantitative status. The increased frequency of meteorological droughts and rising temperatures may only worsen the already compromised situation. The absence of complete and enduring monitoring of groundwater levels prevents the application of some methodologies, which require long time series. The analysis of climate indexes to describe the groundwater level variation is a possible approach under data scarcity. However, this approach may not be obvious for complex aquifers (in terms of scale, intrinsic properties, and boundary conditions) where the response of the groundwater to precipitation is not necessarily linear. Thus, the proposed research deals with the assessment of the response of the Salento aquifer to precipitation variability based on correlations between the Standardized Precipitation Index (SPI) and Standardized Precipitation and Evapotranspiration Index (SPEI) and groundwater levels for nine monitoring wells from July 2007 to December 2011. The study aims at evaluating the ability of the above indicators to explain the behavior of groundwater on complex aquifers. Moreover, it has the general aim to verify their more general reliable application. Results of three different correlation factors outline direct and statistically significant correlations between the time series. They describe the Salento aquifer as a slow filter, with a notable inertial behavior in response to meteorological events. The SPI 18-months demonstrates to be a viable candidate to predict the groundwater response to precipitation variability for the Salento aquifer.
... Coastal carbonate formations are often stable systems that experience relatively high geomorphic inertia; thus, they are well-suited to record the geomorphological features of past sea level oscillations and stillstands, allowing the reconstruction of major paleogeographic events [12]. Indeed, karst landforms produced by the subaerial dissolution of carbonate rocks are found worldwide where carbonate formations are widespread, and at places deeply impact on the landscape [13][14][15][16][17]. Relationships between present morphostructural settings and the distribution of different types of surficial and subsurface karst forms show the importance of lithology, climate, and exposure time in controlling the intensity of morphologic and karst processes [12]. ...
... Coastal carbonate formations are often stable systems that experience relatively high geomorphic inertia; thus, they are well-suited to record the geomorphological features of past sea level oscillations and stillstands, allowing the reconstruction of major paleogeographic events [12]. Indeed, karst landforms produced by the subaerial dissolution of carbonate rocks are found worldwide where carbonate formations are widespread, and at places deeply impact on the landscape [13][14][15][16][17]. Relationships between present morphostructural settings and the distribution of different types of surficial and subsurface karst forms show the importance of lithology, climate, and exposure time in controlling the intensity of morphologic and karst processes [12]. ...
... The coastal plain is mainly made up of calcarenite formations (Marzamemi Formation) and, therefore, a place where karst forms can easily develop. In fact, the carbonate formations, under the action of eustatic and/or tectonic forcing during the Pliocene and the Quaternary, and the consequent repeated changes in the karst base level, led to complex multiphase karst [12], largely outcropping also along the current coast of Marzamemi also. From a geomorphological point of view, the study area is part of the Pantani area of the Vendicari Natural Reserve (Syracuse), a coastal stretch characterized by a series of lagoons parallel to the actual coastline, separated by the open sea by elevated ridges of Tyrrhenian calcarenites and by coastal sand barriers [18]. ...
Coastal depositional environments are the site of complex interactions between continental and marine processes. Barrier islands are highly dynamic coastal systems, typical of these transitional environments, and are affected by sea level changes and the accumulation of transgressive deposits with the landwards migration of the coast. The offshore of Marzamemi (Syracuse Province, Sicily), in the south-eastern portion of the Hyblean foreland, represents an excellent site for the study of transgressive deposits and their connection with the sea-level changes. The available dataset consisted of new high-resolution bathymetry (Multibeam), whose description and interpretation through a Digital Elevation Model (DEM) was integrated with a grid of eighteen seismic profiles (SPARKER). In the investigated bathymetric range, from about −5 m to −60 m, a sensibly different morphological setting between the northern and southern sectors was evident. Within the whole study area, three bathymetric contours (−45 m, −35 m and −20) were identified and assumed as the markers of the main locations of the paleo-coastlines during the recent changes in the sea level. Along the northern sector, three submerged barrier-lagoon systems developed on a calcarenite substratum, marking important steps of the Late Quaternary sea-level rise. They coexisted with numerous karst forms (poljes and dolines). In the southern sector the transgressive environmental evolution was significantly different and submerged lagoons did not form. Here the outcropping calcarenite substratum was affected by the development of paleo-rivers and karsts structures, a tract in common along with many Mediterranean carbonate coastal areas.
... The covers may often contribute to the recharge of deep aquifer through lateral stratigraphic contacts and tectonic discontinuities. In the geological time, the Salento aquifer has been affected by vadose, water table, and transition zone karst processes, favoured by lithology and fractures under the combined effect of tectonics and glacio-eustatic oscillations [43]: thus, Salento currently shows, in addition to endorheic basins, karst plains, fracture zones, dolines, sinkholes, and karst sub-horizontal levels. These elements constitute an interconnected discontinuity system, which determines a high anisotropy of the hydraulic conductivity, with a mean high permeability at regional scale. ...
Salento peninsula (Southern Italy) hosts a coastal carbonate and karst aquifer. The semi-arid climate is favourable to human settlement and the development of tourism and agricultural activities, which involve high water demand and groundwater exploitation rates, in turn causing groundwater depletion and salinization. In the last decades these issues worsened because of the increased frequency of droughts, which emerges from the analysis of Standardized Precipitation Index (SPI), calculated during 1949–2011 on the base of monthly precipitation. Groundwater level series and chloride concentrations, collected over the extreme drought period 1989–1990, allow a qualitative assessment of groundwater behaviour, highlighting the concurrent groundwater drought and salinization.
... The uneven distribution of permeability allows either focused (coastal and submarine springs) or diffuse discharge that, depending on hydraulic condition, ease or impede the ingression of seawater inland [89][90][91][92]. The paleo-karst features (as the conduits of submarine springs and the horizontal karstification levels [93][94][95] may enhance local communicability with seawater along the subterranean estuaries [96,97]. For case (b) (Figure 2), the distribution of fractures, faults, and karst structures along the coast together with their hydraulic behaviour become specific indicators. ...
Coastal karst aquifers show a three-dimensional vulnerability, which consists of the whole of the "intrinsic vulnerability" and the "groundwater vulnerability to seawater intrusion". The results of a study carried out in the Salento karst coastal aquifer (southern Italy) show that temperature, as well as being a reliable tracer of groundwater flow, is also an effective indicator of vulnerability in anisotropic media. The trend of isotherms related to a cross-section of the aquifer thermal field, combined with geological, geomorphological, and hydrogeological information, allows the role of faults and dolines in the mass transport from ground surface to be inferred. Isotherm trends may also give information on the permeability distribution along faults. A specific temperature value evidence the saltwater top, thus indicating the groundwater vulnerability to salinization.
... Selected elevations of geomorphic features and subsurface karst levels have been identified in the Murgia region by a recent study. The mean altitude of low gradient or flat surfaces present in limited elevation ranges was measured through a GIS procedure using a high resolution digital terrain model (Canora et al. 2012c;Fidelibus et al. 2013). The analysis evaluated the area enclosed in selected contour lines and for each selected elevation the analysis quantified the areas limited by pairs of elevation contour lines, each equidistant from the selected elevation of a constant interval of 10 and 20 m. ...
... The ancient Triglio aqueduct, located to the NW of Taranto (Fig. 2), is a hydraulic work composed by two parts: the first is the underground apparatus for vadose flow and groundwater uptake, and the second is the aqueduct that brings the collected water to its final destination. (Canora et al. 2012c)intherange 60-500 m AMSL and their relative intensity (I). The last two columns show the compliance with the elevation of some marine terraces of the Bradanic Foretrough according to Cotecchia and Magri (1967) It shows cultural and constructive boldness and exceptional and unique constructive features, both in the water intake ( Fig. 4) and in the stretch of conveying water, which, in the currently known configuration, reaches Taranto over a length of about 12 km (Fig. 5a, b). ...
Near Taranto (Southern Italy), the water intake of a huge ancient aqueduct develops along the deep Triglio canyon and its branches. The water intake apparatus is a hypogeum stretch for water interception formed by tunnels converging in a single pipe, with a total length of about 4 km. The tunnels, mainly dug into limestones and calcarenites, drain the surrounding vadose zone fed by delayed infiltration of precipitation, small overlying superficial aquifers at the top of canyon flanks, or alluvial deposits covering the canyon bottom. The early hydrogeologists who designed the intake work had an extraordinary knowledge on how to drain vadose flow from unsaturated masses and how to combine the drainage from different zones, thus assuring a perennial water flow. Moreover, they were able to select the most permeable levels, only today clearly identified with advanced hydrogeological knowledge. The tunnels and the pits are in fact located between 130 and 170 m AMSL: this elevation range represents one of the specific elevation ranges recently ascertained in the carbonate platform of Murgia (Southern Italy) as marks of prolonged sea level stands. The geo-archaeological study highlights the role of early hydrogeologists, forerunners of an environmental culture that led to the construction of an engineering masterstroke. It has been working for not less than a millennium, despite climate fluctuations. The sophisticated intake work of Triglio reminds the qanat or foggare, heritage of Persian, Arab and North African culture. It is currently ascribed to the Roman period: however, it may date back to more recent times, probably to a period between the Arab (around 900 AD), and the following Norman or Swabian civilization. The dimension of the work and its outstanding technical value, which allowed its use up to date, deserve disclosure, enhancement and conservation of this geosite as geological heritage.
... Multi-level caves can be associated with past water tables. Their altitude can be related to past sea-level position and the present marine terraces in coastal karst areas (Piccini and Iandelli, 2011;Canora et al., 2012;Nehme et al., 2016). The cave levels often correspond to sea-level highstands, many of them being related to the Eemian transgresssion (MIS 5e). ...
The geomorphological evolution of the Cobiheru Cave shows the influence of the non-carbonate coastal mountain ranges on coastal karst evolution, as well as the temporal distribution of the cold-adapted fauna sites in the Cantabrian Coast. Geomorphological observation and U/Th dating lead to the construction of an evolution model. The model comprises two episodes of cave deposition occurred at ca. 60–70 and 130–150 ka, linked to cold climate conditions, global sea-level lowstands and the erosion of alluvial fans that covered the karst. Moreover, the comparison between the Cobiheru record and some raised beaches identified in previous studies sets the beginning of the sea-level lowering in the Cantabrian Sea during the MIS 5-4 transition. Two palaeoenvironments are inferred based on finding Equus ferus and Elona quimperiana. A wet deciduous forest would have been developed on the emerged marine terrace of the Cobiheru Cave since at least the Middle Pleistocene, and an open landscape with scarce vegetation would have been present at ca. 65 ka. The erosional event identified in the Cobiheru Cave helps to understand the temporal distribution of cold-adapted mammals located in the Asturias region. The probable sites of cold-adapted fauna developed in caves and alluvial fans would have disappeared after 65 ka. Therefore, palaeontological and palaeoclimate research based on cold-adapted mammals suggests the occurrence of an hiatus in the palaeontological record prior to 50 ka. This article is protected by copyright. All rights reserved.
... The strength and deformability of carbonate rock masses depend, therefore, on those of the intact blocks and on their freedom of movement which, in turn, are affected by the discontinuities, as well as by their pattern, orientation and infilling. For a complicated case, the development of karst features, showing irregular geometry, has to be added (De Waele and Parise, 2013). Eventually, the scale of the engineering problem determines the choice between a continuum model and a discontinuum model to represent the rock mass behavior at the stage of design analysis. ...
Classical rock mass classification systems are in practice not applicable to carbonate rocks, especially when these are affected by karst processes. Their applications to such settings could therefore result in outcomes not representative of the real stress-strain behavior. In this study, we propose a new classification of carbonate rock masses for engineering purposes, by adapting the Rock Engineering System (RES) method by Hudson for fractured and karstified rock masses, in order to highlight the problems of implementation of geomechanical models to carbonate rocks. This new approach allows a less rigid classification for carbonate rock masses, taking into account the local properties of the outcrops, the site conditions and the type of engineering work as well.
... In the geological time, the coupling of tectonic subsidence (and/or uplift) and eustatism controlled both water table elevation and vertical and horizontal fluctuations of the transition zone, as well as the thickness of the vadose zone. Such fluctuations engendered the genesis and evolution of both subsurface and surface karst morphologies (Canora, Fidelibus, & Spilotro, 2012). The regional subsidence-driven transgression, which occurred during the Plio-Pleistocene, transformed the Apulian foreland in an archipelago (Mateu-Vicens, Pomar, & Tropeano, 2008;Tropeano & Sabato, 2000). ...
... At the maximum of transgression, only two large areas emerged: They are presently bounded by the old coastline at 425-450 m a.s.l. (Canora et al., 2012;Pieri et al., 1997) and correspond to Alta Murgia. According to the palaeo-geographic history, an aquifer thickness of roughly 200-250 m should have been subject only to vadose diagenesis in correspondence of this area, while some 400 m in the central part of Alta Murgia should have remained unaffected by seawater and brackish water, hypothesizing a max hydraulic head of 10 m above the related sea level (at the maximum regional subsidence-driven transgression). ...
This study aims at recognizing the mechanisms of mass transport between the karst surface and the saturated zone in a morpho-structural relief of the Mesozoic karst carbonate platform of Murgia (Puglia, Southern Italy). The large dimension of the karst aquifer, the regional scale of the flow system, the boundary condition constituted by the sea, and the lack of freshwater springs constrain to the use of wells as monitoring points and limit the study area to the recharge area comprising 986 endorheic basins. The concentrations of non-reactive tracers (nitrates) in the waters of autogenic recharge (from endorheic basins) have been modelled through the evaluation of effective infiltration, land use, and nitrogen surplus, with reference to a time window, which includes a low precipitation period followed by significant rainfall events. The comparison between the modelled nitrate concentrations and the nitrate concentrations measured in ground waters, coupled with the analysis of groundwater chemograms and records of hydraulic heads (all referred to the same time window), allows inferring the mechanism of mass transport between the karst surface and the groundwater table. The mass transport conceptual model requires the presence of the epikarst. The infiltration of significant rainfall in the endorheic basins after a low precipitation period displaces waters stored in the epikarst towards the saturated zone. Ground waters in the post-evet period show higher concentrations of nitrates, lower concentrations of Total Organic Carbon and higher Mg/Ca ratios than both those of the pre-event period and the autumn-winter recharge period. The post-event recharge from epikarst storage determines a transient hazard of groundwater pollution with a time lag from the occurrence of the heavy rainfall.
