Geotouristic Itinerary in Apulia - Guide

Version 1.1 November 2014 1 / 36

Guide of the geo-touristic itinerary Tourism and Geology in eastern Salento

GUIDE

OF THE GEO-TOURISTIC ITINERARY

Tourism and Geology in eastern Salento

within the framework of the activities

of the

Service of recognition and check of the geological heritage, with

identification of the geosites and places of geological interest of the

Apulia Region

(L.R. 33/2009 - action 4.4.1 - line 4.4 - axis IV - P.O. FESR 2007 2013)



AUTHORS

The document has been produced by:

Silvia Ciurlia

Flaviana Defilo

Antonello Fiore

Mario Parise



INDEX

Authors 2

Index 3

1. Foreword 4

2. General features of the itinerary by car 5

3. Hiking 7

4. Description of the geosites 7

4.1. Deposits with crabs and ittiodontoliti at Porto Craulo 8

4.2. Pliocene succession at the Otranto harbour 10

4.3. Aqueduct Carlo Magno 11

4.4. Bauxite mine Le Orte 13

4.5. Tsunami deposits at Torre Sant'Emiliano 15

4.6. Deers Cave 16

4.7. Oligocene calcarenites with rodolites at Porto Badisco 18

4.8. Lepidocycline Calcarenites at Villaggio Paradiso 20

4.9. Eocene limestones at Torre Specchialaguardia 22

4.10. Thermal area of Santa Cesarea 24

4.11. Li tamantili 25

4.12. Masso della Vecchia 28

4.13. Alimini Lakes 31

5. Something more (in-depth materials) 33

5.1. Morphological characters 33

5.2. Geology and tectonics 33

6. Glossary 34



1. FOREWORD

The present guide illustrates a proposal of geo-touristic itinerary (entitled Tourism and Geology of eastern Salento) that, in addition to the specific sites of geological interest, also includes naturalistic and historical-cultural issues. By using the existing path network, the itinerary allows to transfer information to a wide public about sites of the geological heritage of eastern Salento, that represent important evidence of the history and the geological, geomorphological, hydrogeological and pedological evolution of the territory.

The work is part of the activities of dissemination of the interdisciplinary project Service of recognition and check of the existing geological heritage, with identification of the geosites and places of geological interest of the Apulia Region, which has as main goal the implementation of the Regional Inventory of the Geosites, as expected by article 3 of the Regional Law of Apulia no. 33/2009 Safeguard and exploitation of the geological and speleological heritage (action 4.4.1 - line 4.4 - axis IV - P.O. FESR 2007 - 2013). Such Inventory, realized after a detailed recognition and check of the geological heritage of the regional territory, will represent a useful tool for both the geological knowledge of the territory, and the base to further promote the preservation and exploitation of the geological heritage.

One of the primary activities to guarantee such preservation is precisely represented by developing a careful and responsible geo-tourism.

The area interested by the present itinerary is object since a few years of touristic fruition, mostly concentrated during the summer season. This project has as goal to encourage the growing touristic interest for the natural features, that may contribute to differentiate throughout the year the touristic presence, which attractions may derive also from the geological heritage of scientific and economic significance.

The itinerary develops through the 13 geosites identified during the inventory phases of the project (the related sheetforms are available at the internet site of the project). Along the itinerary, or in its immediate surroundings, others places of geological interest are also present; these are not described in this guide, but might be used to integrate the itinerary in the future.

The present itinerary is accessible by car (see 2), but it also shows hiking paths to reach some of the geosites (see 3). Most of the itinerary develops along the coast, thus permitting to have panoramic views of the coastal landscape of Salento; the western part of the itinerary, making a loop in its northern sector, moves, on the other hand, in the Salento countryside, among its most typical features, with olive tree groves and the many testimonies of the local rural architecture (dry stone walls, pagliare, masserie).

For logistic reasons, and for the importance of the site and its fame as well, the recommended starting point is the town of Otranto. Nevertheless, the itinerary can be followed starting by any of the geosites, since it does not have a specific sequence in the succession of the stops.



2. GENERAL FEATURES OF THE ITINERARY BY CAR

The proposed itinerary, about 53 km-long, crosses a slightly ondulated area of western Salento, with multiple views on the Otranto channel. The landscape is characterized by a series of ridges, locally called Serre (maximum elevation 126 m a.s.l.), elongated in NW-SE direction, with intervening plains, located at lower elevations.

Following the beginning of the itinerary with recommended starting point at Otranto (coordinates of the starting/arrival point: WGS84UTM33N X = 797026; Y = 4450031; WGS84 Long: 18.48687913; Lat: 40.14814059), the northern sector of the town, at the final rim of the northern cape of the Otranto bay, is reached; here is the geosite "Deposits with crabs and ittiodontoliti of Porto Craulo" ( 4.1), of significant palaeontological importance, showing abundant fauna and many organisms of low-depth sea, in growing position.

On the opposite side of the bay, moving from the Otranto harbour, the geosite Pliocene succession of the Harbour of Otranto ( 4.2) can be easily reached, along the coastline, here showing the character of rock cliff: this site has a primary scientific interest in the fields of geological stratigraphy, palaeontology and sedimentology, since it shows clearly the geological contact among two formations of different ages, and deposited in different environments of sedimentation.

At the immediate boundaries of the town of Otranto, along the Idro Valley, the geosite Aqueduct Carlo Magno ( 4.3) is located: this is an interesting underground work of hydraulic engineering, that represented the first example of public aqueduct in the Lecce province. The subterranean structure cannot be visited by tourists. South from Otranto, in locality Le Orte, you can reach what is certainly one of the most appealing sites of the whole itinerary: the geosite Bauxite mine Le Orte ( 4.4), where the contrast in colors among the lake hosted at the bottom of the depression originally used for extraction and the surrounding rocks is of great emotional impact, in any light condition.

Leaving Otranto in southward direction, in a few minutes you can reach, following the Province Road 87 (SP 87) Palasca Cape, the extreme eastern cape of Italy, and, keep going along the same road, farther south there is the geosite Tsunami deposits at Torre SantEmiliano ( 4.5), near the coastal tower of the same name (one of the many sighting towers, built for defensive purposes in order to point out the arrival of enemies from the sea): the geological interest here derives from accumulation of large blocks, due to sea storm waves that deposited them at a distance of some 80 m from the coastline. A downhill stretch of the road, still along the SP 87, allows to reach the bay of Porto Badisco, where on the hydrographic left side two sites of interest are located: namely, the geosite Deers Cave ( 4.6) and the geosite Oligocene calcarenites with rodolites of Porto Badisco ( 4.7). The first is a karst cave, not open to the public, of remarkable importance for the exceptional nature of the wall paintings of Neolithic age, made with bat guano and red ochre, portraying geometric figures, both humans and animals. The site, safeguarded by the Soprintendenza per i Beni Culturali, is entirely fenced and can be only reached at a distance, approaching it from the bay of Porto Badisco. At the northern margin of the same bay, the geosite of calcarenites with rodolites (algae nodules) is visible; these deposits



indicate peculiar sedimentary conditions during the geological time of formation of the rocks.

Keep going, from Porto Badisco toward the south, along the coastal road (from now on named SP 358), in direction of Santa Cesarea Terme, there is a few-km long stretch with high rock cliffs. In this area, as well as to the north, near Palasca Cape, the mountains of Albania can be seen at a distance in clear sky conditions. Near Villaggio Paradiso the geosite Lepidocycline Calcarenites of Villaggio Paradiso ( 4.8) is located: this, too, is of both palaeontological (for abundance and size of the fossils) and sedimentological (since it testifies a particular environment of deposition) significance. Further on, along the same road SP 358, a road cut allows to observe one of the rare outcrops of Eocene age, at the geosite Eocene limestones of Torre Specchialaguardia ( 4.9).

Once reached Santa Cesarea Terme, you are at the geosite Thermal area of Santa Cesarea ( 4.10), where the health spa of Santa Cesarea exploits the sulfur waters coming out from several coastal caves. In particular conditions of sea current and wind, white plumes (produced by the abundant presence of sulfur) can be seen on the sea surface in front of the cave entrances. At the southern margin of Santa Cesarea, the geosite Li Tamantili ( 4.11) is present, which name derives from the local dialect: it consists of the evidence left by ancient quarries for the extraction of building material, that were worked down to the sea level. Even though the Santa Cesarea geosites are partly visible from the land, the ideal situation to have their best appreciation is that from the sea; sea conditions permitting, therefore, a boat tour along this stretch of the coastline is strongly recommended.

At this point of the itinerary it is necessary to go back along the SP 358, from Santa Cesarea Terme to Porto Badisco, and from here moving inland, toward Uggiano La Chiesa, and then Minervino di Lecce (along SP 56); once the village of Minervino is left, you need to move toward Palmariggi, along the SP 59. About halfway between the two villages, a diversion on the lefthand side brings to the geosite Masso della Vecchia ( 4.12), in a large olive tree grove with presence of huge blocks of rock that created monolithic structures (produced by karst and erosional processes), and that are at the origin of many folk legends.

The itinerary goes ahead to the north, moving from Palmariggi along some secondary roads that allow to get a further glimpse of the Salento countryside, in a landscape characterized by slightly ondulated surfaces and low plains, before joining the SP 48, and further on the SP 341, toward the last geosite of the itinerary: the Alimini Lakes ( 4.13). These occupy two tectonic depressions, and are directly fed by groundwaters by means of a number of springs on the western side, and by freshwater from several channels. Beside the lakes, along the coastline a different landscape can be here appreciated, with a low coast in soft rocks or sands, and development of sand dunes.

For more detailed descriptions of the geosites, the reader is referred to the following pages of this guide.



3. HIKING

Some parts of the itinerary are hiking paths, necessary to reach the geosite of interest along earth walkway or natural landscapes. They consist of short streches, that allow to further appreciate the geological features of the area, combined with others of botanical, faunistic and naturalistic interests. Given the characters of the Salento territory, mostly plain or with slight slopes, the hiking is essentially without any difficulty, developing for great part along horizontal paths. The total length of the hiking parts is slight more than 3 km.

The first walking paths are within the inhabited area of Otranto, to reach, respectively, the geosites "Deposits with crabs and ittiodontoliti of Porto Craulo" ( 4.1), and Pliocene succession of the Harbour of Otranto ( 4.2). The geosite Aqueduct Carlo Magno ( 4.3) requires, too, a short hike along the Idro Valley, without any particular difficulty. To fully enjoy the beauty and the suggestion of the geosite Bauxite mine Le Orte ( 4.4), the recommendation is, once left the car, to approach the site by walk, and to follow its perimeter (keeping at a safe distance from the about vertical walls), on a terrain of terra rossa with abundant bauxite nodules. Especially on the western side, care must be taken when moving along the deep incisions and gullies, also because of the slippery clays, especially after rain.

Hiking to approach the site is also required to reach the geosite Tsunami deposits at Torre SantEmiliano ( 4.5): once left the car at the margins of road SP 87, a walk of some 15 minutes will bring you close to the coastline, along a rocky landscape with low-medium slope.

Eventually, the geosite Masso della Vecchia ( 4.12) is the last one for which a hiking is necessary: moving from the SP 59, the walkway follows a path with asphalt, before moving to the NW to enter the olive tree grove hosting the rock blocks of interest. The hike is entirely on flat terrain, without difficulty.

For more detailed descriptions of the geosites, the reader is referred to the following pages of this guide.

4. DESCRIPTION OF THE GEOSITES

The geo-touristic itinerary here proposed allows to appreciate the geomorphological features of eastern Salento, together with its valuable natural landscape and the links with rural architecture, history, social development and geo-resources.

The itinerary partly develops in the Parco Naturale Regionale "Costa Otranto - Santa Maria di Leuca e Bosco di Tricase", established with regional law (L.R.) no. 30/2006 to safeguard the naturalistic heritage of the area, of very high scientific and cultural values (www.parcootrantoleuca.it/). Composed of 13 sites of observation with illustrative panels, it



includes an itinerary by car and some hiking paths, through which it is possible to observe the main geological units and their relationships.

In the following, each geosite along the itinerary is described in detail, starting, as recommended, from Otranto and moving southward along the coast, to then continuing inland before going back toward the coast at the northern end, near the Alimini Lakes.

In the description of the single geosite, an effort was made to use an easy-to-comprehend language, by limiting as much as possible the use of technical terms; however, since some technical terms had necessarily to be included, the Glossary ( 6) at the end of this guide provides synthetic explanations for the terms that are written in bold in the text.

4.1. DEPOSITS WITH CRABS AND ITTIODONTOLITI AT PORTO CRAULO

The geosite of Porto Craulo, at the Frascio locality, north of Otranto, is a place of high landscape value and offers a number of interesting points for tourists; further, it represents a geosite of reference for similar and coeval deposits at Roca Li Posti and San Andrea (further north along the Adriatic coastline), as concerns the palaeontological characters. Detailed studies were carried out at the site in the middle sixties and the early eighties of last century: the deposit consists of a yellowish and weakly cemented calcarenite made of fossil fragments, similar for lithologic features and microfauna contents to the calcareous organogenic sands of Cape of Otranto.

Figure 1 General view of the site (photo: S. Margiotta).



The abundant macrofauna is represented by rests of isolated Corals, Brachiopods, Cirripedes, Echinids, Lamellibranches, Gastropoda and Chelonia. There is a remarkable presence of Decapoda Crustaceans brachiuri among which specimen of Cancer sismondai Meyer; Varola, 1965, are mostly represented, all in position of growth: these taxa indicate a neritic (or sub-littoral) environment, with low sea level, calm waters and slow sedimentation. The comparison with the species living today show how the Cancer genus has adapted to deeper seas.

Other important discoveries are the ittiodontoliti (fossilized fishes teeth), and in particular the species Notidamus griseus, Sparus cinctus e Pagrus Mauritanicus.

Figure 2 Detail of the succession (photo: S. Margiotta).

Figure 3 Crustacean from Porto Craulo (photo: A. Varola).



4.2. PLIOCENE SUCCESSION AT THE OTRANTO HARBOUR

The geosite, that can be reached by a short walk from the harbour of Otranto, has scientific interest in the field of stratigraphic geology, palaentology and sedimentology, since it clearly shows the contact between two geological formations of different ages, formed in distinct environments of sedimentation. The lower unit, that shows aspects similar to the Trubi (geological formation defined in Sicily), is the Formation of Leuca (Lower Pliocene): it indicates an environment of open sea (outer carbonate platform) with low sedimentation rate, and is made of whitish marls with intercalation of pale-yellow sandy levels. Typically unbedded, it shows local bedding, due to presence of thin, cemented and often oxided, levels.

Figure 4 The Pliocene succession at the Otranto harbour (left), and detail (right) of the contact

between the deposits of the Leuca Formation (Trubi) and the Uggiano la Chiesa Formation (photo:

S. Margiotta).

A phosphate crust in the upper part of the unit, thick up to 20 cm, shows bio-erosion from

lithofagi organisms. Isolated fossils are locally found (Amusium, Chlamys,

Neopycnodonte). The overlying formation is that of Uggiano la Chiesa (Middle-Upper

Pliocene), related to marine environments of low depth, as testified by the microfauna



benthos: at its base, there is a conglomerate with clasts of variable lithologic origin, with

diameter that can reach 50-80 cm, dark brown in color with greenish tones, immersed in a

yellowish matrix of calcareous mud with fossil remains. The color of the clasts has to be

related to processes of phosphatization, that also brought to the formation of small

nodules, dispersed within the sediment. Among the clasts, that are often affected by

biological erosion, the presence of bauxite nodules (pisolites) and glauconite granules

has been observed. The matrix presents several fossils, with prevailing Ostrea (even of

great size) and Chlamys; in addition, Flabellipecten, Spondylus, Amusium, Conus,

echinids, corals, and fish tooth are also present. Gradually, but with high rate, the clasts

decrease upward, until leaving space to the most typical facies of the geological unit, that

is medium-fine, yellowish detritic-organogenous limestones, locally marly limestones.

Figure 5 Detail of the phosphatic breccia (photo: S. Margiotta).

4.3. AQUEDUCT CARLO MAGNO

The Carlo Magno aqueduct, and the related hydraulic works, are among the first examples of public aqueducts built in the Lecce province in modern times. It is a remarkable work of hydraulic engineering from the historical standpoint, in a location highly significant for the comprehension of the links existing among geomorphological and hydrogeological setting of the territory, human settlements, and land use.

The Idro Valley is a small fluvial valley running at the boundaries of the town of Otranto, and is made of two main branches, the Carlo Magno and San Giuseppe channels.

The geological setting of the aqueduct is characterized by two litho-stratigraphic units, respectively of the Lower and Middle-Upper Pliocene. They are marly biomicrites,



hosting well-known water tables, exploited since ancient times from two springs, known as Carlo Magno springs.

The complex of hydraulic works develops around the draining gallery tapping the two springs, that enters the valley flank for some 70 metres, with average height of about two metres. At the base of the gallery, the water from the springs flows in a small channel, 40-50 cm-wide and deep, that was originally coated by plates of Pietra leccese. The springs are located at the end of the gallery: the first comes out from a small lateral branch, about 5 m-long, whilst the second is about at the terminal part of the main gallery.

At about 25 m from the entrance, a vertical shaft goes up to the ground surface. In several locations the marks left by the tools used for the excavation are visible. Many small artificial hollows on the walls of the gallery had the function to host oil-lamps.

In the nearby area, another underground gallery, partly flooded, worked as discharge channel; it is linked to the ground surface through vertical shafts.

Figure 6 Carlo Magno Aqueduct: view of the entrance of the draining gallery (photo: G. Selleri).

The aqueduct pre-dated the realization of the Apulian Aqueduct, and that was put out of work when this latter entered in function. The site represents, therefore, a place where it is possible to observe the stratification in time, as produced by the technological progress, of the modalities by means of which man tried to exploit the opportunities offered by the geological peculiarities of the territory.



The Carlo Magno aqueduct was realized in its present configuration in 1917 by the Corps of Engineers of the Royal Navy, that bear its expenses until 1925, together with other similar aqueducts built for military reasons during the First World War at Gallipoli and Leuca, and transferred it, initially as provisional budget, and later definitively in 1929, to the Otranto Municipality.

The Carlo Magno aqueduct remained in function until 1940; after that time, it is in state of complete abandonment. The hydraulic structure is not open to public visits.

4.4. BAUXITE MINE LE ORTE

In locality Le Orte, just south from Otranto, it is possible to visit an abandoned site of extraction where an open mine for production of bauxite was active until the middle 1970s. The mining activities affected a portion of the carbonate bedrock, consisting of a succession of layers from the Upper Oligocene; in detail, it was a thick deposit of residual materials from karst processes, with abundant bauxite pisolites, widespread at the surface in the immediate surroundings of the mine.

This site was not the only bauxite deposit in Salento, since other important ores were found in the Palmariggi and Poggiardo areas. The ores consisted of unbedded fillings of deep pockets and fissures within the bedrock. The bauxite ores in Salento were, obviously, of interest for the mining companies, and, for some times, they resulted to be among the first sites of production at a national level. With time, however, their importance resulted to be lower than expected. The mine at Le Orte was abandoned in the second half of 1970s, and no action dedicated to a sort of environmental recovery started. At the bottom of the deep topographic depression created by the mining activities, a small and peculiar lacustrian ecosystem formed. The color of the rocks cropping out, in contrast with the blue of the lakes and of the sky, makes the site highly suggestive, with a number of different tonalities in the natural environment that change following the course of the day and the different light conditions.

The sequence cropping out along the walls of the depression consists of a succession of layers emplaced in a climatic regime of tropical type during the Upper Oligocene. In detail, an alternance of deposits of continental environment (of both fresh water and sub-aerial), brackish transition (marsh and/or coastal pond) and marines can be identified.

In the Oligocene succession four new species (-iv) and one subspecies (v) of mollusk fossils have been discovered, so far only known in Salento: (i) Tectarius (Echininus) japigiae; (ii) Pseudamnicola messapica; (iii) Pseudamnicola palmariggii; (iv) Stenothyrella salentina, (v) Hydrobia dubuissoni hydruntina.



Figure 7 General view of the bauxite mine near Otranto (photo: Geositi Working Group).

Figure 8 Along the excavation walls a Cenozoic succession crops out, deposited in environments

ranging from the continental and the low-depth marine (photo: Geositi Working Group).



Figure 9 Terra rossa deposits, affected by erosional action by the running waters, contribute to

make the landscape highly appealing (photo: Geositi Working Group).

4.5. TSUNAMI DEPOSITS AT TORRE SANT'EMILIANO

Evidence of a tsunami that hit the Salento coasts are well documented along a stretch of coastline extending from Otranto to the Cape of Santa Maria di Leuca. In particular, near Torre Sant'Emiliano, a few kilometers south from Otranto, it is possible to observe an accumulation of large rock blocks that, pulled up from the tsunami waves, have been deposited at a distance of more than 80 m inland. The larger blocks weigh about 70 tons, and form two bars along a strip about 30 m-wide, and some 2,5 km-long. The highest elevation of the deposit is about 11 m. Groups of superimposed blocks indicate that the wave came from SE-SSE. Radiocarbon dating of marine shells found in the debris, and of pottery fragments within the deposit below the blocks, suggest for the emplacement a date going back to about three centuries ago.

Among the several earthquakes that historically hit Salento, one of the most important is that occurred during the night of February 20, 1743: the shock was felt in a wide area, on the opposite side of the Adriatic Sea, and in the whole southern Italy as well. According to the sources, about 180 victims were recorded in Apulia. The towns in Salento that suffered the most severe effects were Francavilla Fontana (in the Brindisi province) and Nard (in the Lecce province), this latter with about 150 fatalities. Severe damage were registered in many other localities between Brindisi and Taranto. The earthquake caused also a tsunami, for which the historical sources only describe some effects in the harbour of



Brindisi. As a matter of fact, with the exception of the town of Otranto, the coastline between Brindisi and Santa Maria di Leuca was at that time practically uninhabited, due to the malaria that infested the wide coastal marshlands.

Southern Apulia is typically not considered among the seismic areas of Italy. However, historical and geological evidence show that, in a recent past, Salento was hit by earthquakes, and by strong tsunami along the coastlines. This area, in particular, feels sensibly also the effects of seismic shocks having the epicenter along the Albanian coasts and in proximity of the Ionian islands; typically, the effects in Salento of earthquakes located in the Southern Apennines, Tavoliere and Gargano, are less strong.

Figure 10 General view of part of the area interested by the tsunami; the blocks bermi s

highlighted by the red line (photo: Geositi Working Group).

4.6. DEERS CAVE

Deers Cave (also named Aeneas Cave), is a karst cave internationally known as the site containing the most remarkable complex of cave paintings of Neolithic age in Europe. It is located nearby the bay of Porto Badisco, some 4 km from Uggiano la Chiesa. The main access opens at some 200 metres from the shoreline, at elevation of about 30 metres a.s.l.



From the geological standpoint, the karst system develops in the Oligocene formation of the Porto Badisco Calcarenites. Its development is sub-horizontal, with total length of 1500 metres, that makes it one of the longest system in Apulia, and the longest in Salento.

The cave consists of three main galleries, about parallel and with sub-horizontal development, NNW-SSE oriented, and connected by secondary branches. Some parts of the karst system are interested by the presence of the water table.

Deers Cave was discovered in 1970, and is listed at the Register of the Natural Caves of Apulia Region with the number PU 902. The peculiarity of the site is represented by the presence of many neolithic cave paintings, realized with bat guano and red ochre, depicting a series of geometrical forms, humans and wild animals.

The origin of the cave is related to karst processes in coastal area: in particular, the hypogean forms related to phreatic environmental conditions, or to the action of air condensation, are very diffuse. Secondary calcite deposits characterize several sections of the system, too.

Figure 11 View of one of the entrances to Deers Cave (photo: G. Selleri).

The great development of the karst system, together with the traces of its neolithic occupation, makes the geosite a unique location in the Apulian speleological panorama, with multiple intersts in different fields of the scientific research (archaeology, palaeontology, geology, palaetnology, etc.).



The archaeological excavations pointed out that the filling deposits of the cave, below the anthropogenic layers, is made of silty sands containing Pleistocene fauna (Equus Hydruntinus and Bos Primigenius).

Deers Cave is not open to the public, and its entrances are closed by gates and wall structures, realized by the Soprintendenza per i Beni Archeologici della Puglia in order to protect the site.

4.7. OLIGOCENE CALCARENITES WITH RODOLITES AT PORTO BADISCO

The bay of Porto Badisco is a tourist target of high historical and landscape values, in addition to the geological importance. The area, according to what described by Virgil in his Aeneid, should correspond to the first landing place of Aeneas, during his journey back to Italy, following the escape from Troy. This bay, which origin is related to the partial submergence of a fluvial valley, opens along the coast between Santa Cesarea Terme and Capo dOtranto. Porto Badisco represents the type-locality of the Formation of the Calcarenites of Porto Badisco. At the northern flank of the bay it is possible to observe the contact between the calcarenites and the underlying Formation of the Castro Limestones, in turn lying over the Santa Cesarea Limestones. The Calcarenites of Porto Badisco are characterized at the base by the presence of magnificent examples of rhodoliths (algae nodules), forming a lenticular body, thick up to 1,5 m. The rhodoliths are spheroidal to ellissoidal in shape, with growth morphology mostly columnar, and locally concentric; they have diameter ranging between 5 and 10 cm, the core generally consiting of a calcarenite clast, and are immersed in a bioclastic matrix with macro-foraminifera. Massive, poorly cemented calcarenites, intercalated to marly levels, lie over this base interval.

Figure 12 View of the northern side of the Porto Badisco bay (photo: S. Margiotta).



The Calcarenites of Porto Badisco are deposits of low depth marine environments. The taxonomic composition of the algal association and of the macro-foraminifera indicates an environment of sedimentation located in the oligo-photic zone. Deposition of these sediments occurred in sub-tropical to tropical waters. The lithofacies with rhodolith represents the filling of a depression, a likely channel, controlled by the topography inherited by the bedrock.

Figure 13 View of the outcrop with rodolites (photo: S. Margiotta).

Figure 14 Detail of rodolites at the bottom of the unit (photo: S. Margiotta).



4.8. LEPIDOCYCLINE CALCARENITES AT VILLAGGIO PARADISO

South from Porto Badisco (Otranto), just west from the road leading to Santa Cesarea, the locality of Villaggio Paradiso is situated. The road linking the site to the sea is for most part excavated in trenches, and allows to observe a mostly sandy to calcarenite sequence belonging to the geological unit of the Porto Badisco Calcarenites.

The main character of the outcropping, which makes it a geosite, is the presence of large and well-preserved Lepidocycline, in samples dispersed within the deposit. Lepidocycline, belonging to the Foraminifer subfamily, lived from the Eocene to the Miocene in the European and Indo-Pacific areas, and have a diameter as large as 7-8 cm, and a flat shell with a slight central bulge. In addition to the Lepidocycline, quite abundant in the deposit are the reworked nummulites, with well-preserved samples of Amphistegina, Neorotalia and Nephrolepidina.

The presence of the large Lepidocycline is indicative of a sedimentation environment within the deepest sector of the oligo-photic zone. Further, the presence of reworked nummulites and the decrease in the fine fraction of the matrix, indicate some hydrodynamic action that had to characterize the sea bottom.

Figure 15 View of the outcrop (photo: S. Margiotta).



Figure 16 Detail of an interval rich in Scutelle (photo: S. Margiotta).

Figure 17 Detail of an interval with small Lepidocycline (photo: S. Margiotta).



4.9. EOCENE LIMESTONES AT TORRE SPECCHIALAGUARDIA

The outcrop showing the best exposition in Salento of the Eocene succession of the Torre Specchialaguardia Limestones is located along the coastal road connecting Porto Badisco to Santa Cesarea, at about km 12. This road cut has been individuated as geosite, due to the rarity of Eocene outcrops in Salento. Its importance stands in the fact that no geological section where the whole succession, from the Cretaceous units to the Oligocene, has been identified, due to the rarity of Eocene sediments, that generally have limited thickness or do not crop out.

Near Torre Specchialaguardia, the succession is exposed for about 80 meters and lies with an angular unconformity over the Cretaceous limestones. Four main lithologies can be identified, differentiated on the basis of the sedimentological features and of the fossils. Among these latter, foraminifera prevail (they allowed to precisely date the succession through bio-chronostratigraphy), but red algae and corals are also present. In one of the intervals, glauconite fillings within the voids present in the Eocene limestones have been found.

The succession is inclined (clino-stratification) and is exclusively represented by facies of forereef slope, that was probably limited to stretches of the eastern Salento coastline during the Eocene.

Figure 18 View of part of the succession (photo: S. Margiotta).



Figure 19 Detail of the white limestones with cavities filled by glauconite (photo: S. Margiotta).

Figure 20 Detail of the succession of white limestones with corals and algae (photo: S. Margiotta).



4.10. THERMAL AREA OF SANTA CESAREA

The thermal area of Santa Cesarea is located in a sector extending from the coast to locality Cupa inland, in a stretch of coastline characterized by morphological steps and terraces of marine abrasion. The area is well known for the presence of sulphur hypothermal groundwaters coming out in correspondence of four main coastal caves: Gattulla, Sulfurea, Fetida, and Solfatara (or Sulfurara). The first three are located within or in the immediate surroundings of the health spa area, whilst the Solfatara cave opens to the south, along the coastline. All the mentioned caves are included in the Register of Natural Caves of Apulia Region, managed by the Apulian Speleological Federation (the association joining all the grottos in the region).

The sulphur groundwaters of the thermal area of Santa Cesarea are exploited by means of wells, at the localities Cupa and Albergo Palazzo (this latter is located along the coast), at temperature comprised between 28 and 30 C, and are used in the health spa for many therapeutic applications and beauty treatments.

The origin of the sulphur groundwaters seems to be related to connate waters, confined below the Adriatic Sea by thick impervious sedimentary covers.

Figure 21 View of the thermal area, from the north (photo: G. De Giorgio).



Figure 22 View of the thermal area, from the south (photo: G. De Giorgio).

4.11. LI TAMANTILI

The quarrying area of Santa Cesarea is located along one of the most remarkable coastal stretches of the Salento peninsula, characterized by rock cliffs and intervening bays with different shape and size, as the result of the anthropogenic activities carried out in time. In this area the extraction of the rock material passed through several production phases, the first ones with hand work, that were later changed into cycles of production of industrial type. As a consequence, the excavation fronts in carbonate rocks, too, show different typologies. In the most ancient sectors of activities, an arrangement in steps is present, that derives from the technique to quarry the blocks starting from the highest sector, and gradually moving toward the sea. Later on, the quarrying technique became more efficient, developing vertical walls and creating magnificent cliffs, overhanging the sea, often canceling the more ancient evidence of activities. The quarrying activities along the coast at Santa Cesarea represents an interesting example of how the anthropogenic actions have modified the natural coastline, creating with time a target for tourists.

Further, the quarry walls allow to observe features in the rock masses that would not have been visible otherwise, due to weathering processes. A classical example is the sedimentary succession cropping out at Porto Miggiano, near the localities Archi and Fontanelle where, thanks to steps in the rocks, the rock features are easily visible notwithstanding the verticality of the cliffs. The succession belongs to the Pleistocene unit of the Gravina Calcarenite, in unconformity over more ancient units (Cretaceous and



Eocene-Miocene), with maximum thickness of some 40-50 m. The peculiarity of these deposits stands in the presence of magnificent layers, inclined up to about 30, dipping toward south, and with a thickness ranging from a few cm to more than 1 m: they are carbonate deposits, with rare clay intercalations, rich in fossils (red algae, briozoi, echinids, brachiopods, rare corals and bivalves, in addition to benthic and plankton foraminifera). The deposits are generally bioturbated, and only locally they show parallel laminations. Among the other typical sedimentary structures (that is, formed at the time of the deposition of the geological layers) there are also uphill inclined strata, and layers deformed due to submarine slides (slumps). Overall, these features allow to interpret such rocks as deposits of scarp, and of the base of a underwater scarp. They can be observed also in other bays along the coastline between Otranto and S. Maria di Leuca, and form bodies with a shape reminding that of the aprons wear by the housewives (tamantili in the local dialect).

Figure 23 View of the quarry walls in calcarenites, locality gli Archi (photo: S. Margiotta).



Figure 24 Detail of the sedimentary structures along a wall in the calcarenites, locality gli Archi (photo: S. Margiotta).

Figure 25 Calcarenite layer, showing intense bioturbation (photo: S. Margiotta).



Figure 26 Calcarenite succession cropping out in locality Fontanelle (photo: S. Margiotta).

4.12. MASSO DELLA VECCHIA

Il Masso della Vecchia (The Rock of the Old Woman) is a boulder of Pietra Leccese (fine calcarenites, thinly bedded and poorly cemented, followed upward by a more resistant homogenous rock layer, about 1 m thick), almost entirely isolated from the bedrock, located at the boundaries of a wide, centuries-old, olive tree grove at the top surface of Serra di Poggiardo. Due to its peculiar shape, similar to large monolithic structures, in the past many legends have been elaborated about its origin; actually, it represents a rarity in the geomorphological field, and has a primary scientific interest.

The origin has to be attributed to the processes of chemical and mechanical degradation (weathering) by meteoric waters on calcarenite deposits, following the final emergence of the area during the Pliocene; the later removal of the weathered products and of the soil in karst swallow holes within the underlying Mesozoic limestones, led to a progressive lowering of the topographic surface, and to cropping out of the highest portions of the calcarenite surface; at the same time, in the topographically depressed areas the cover of the bedrock, consisting of residual deposits, was still present. One of these swallow holes opens at the bottom of a deep doline, few tens of meters north from the site.

In this geomorphological setting, the meteoric waters flowing from the highest reaches along the slightly inclined flanks, infiltrated into the cover, creating the formation of incisions in rapid deepening (marginal corrosion), thus highlighting the thinly bedded levels of the local stratigraphic succession.



Continuing such a process, the terrain around was removed, and left as relict this residual karst macro-form, indicated as Masso della Vecchia.

Figure 27 Deep doline, partly filled by man, in the proximity of Masso della Vecchia (photo: P.

Sans).

Figure 28 Karst micro-forms developed below the soil cover are well visible on the rock blocks

(photo: P. Sans).



Figure 29 One of the strange karst residual forms in the Masso della Vecchia area (photo: P.

Sans).

Figure 30 Masso della Vecchia (photo: P. Sans).



4.13. ALIMINI LAKES

The area of the Alimini Lakes, with its low plains and the slightly ondulated surfaces represent from the landscape standpoint an ideal site for hiking, and has a high scientific interest in the fields of geomorphology, hydrogeology and structural geology. Formed from the evolution of a palustrian environment that characterized the territory more than 5000 years ago, the lakes today occupy two tectonic depressions, elongated about parallel to the coastline for 7 km, and resting over a bedrock of Pliocene age, consisting of calcarenites alternated to sands and clay sands. Separated by a rock spur, incised by the canal named Lu Strittu, the lakes are directly fed by the groundwater through a number of springs on their western sides and by the fresh water coming from several canals.

The Zuddeo canal, the Traugnano swamp and other drainage canals feed the larger lake, Alimini Grande, which, as an effect of the marine intrusion through the canal Bocca degli Alimini (Alimini Mouth), is characterized by brackish water: in particular, the salinity decreases in the whole basin from the sea inland from values of 34,8 to 2,2 .

The Rio Grande canal feeds the smaller lake, Alimini Piccolo or Fontanelle: with average depth of 0,70 m, it has an area of only 0,5 km2; during the last century, a dam was built to limit the flow of brackish water from Alimini Grande, thus making Alimini Piccolo a fresh water lake.

Figure 31 View of the Great Alimini lake (photo: S. Margiotta).



Figure 32 Detail of the stretch flowing into the channel Alimini Mouth (photo: S. Margiotta).

Figure 33 View of the Small Alimini lake (photo: S. Margiotta).



5. SOMETHING MORE (IN-DEPTH MATERIALS)

5.1. MORPHOLOGICAL CHARACTERS

The geo-touristic itinerary crosses morphologies typical of the Salento Peninsula, that is a series of wide surfaces, about all of Quaternary age, dislocated at different elevations (from the highest at some 120 m down to a few meters a.s.l.), linked by low-inclined scarps (10-20), mostly NW-SE and NNW-SSE striking.

The physiographic characters of the coast are quite different when moving from Otranto in the two opposite directions: in correspondence of the town, the coast is a rock cliff, and this type of configuration continues to the south with even higher relief; further, several karst caves, both above and below the sea, are present in this area. The coastline north from Otranto is, on the other hand, very different, showing an overall linear trend, and being a low coast in soft rocks or sands, with diffuse presence of sand dunes and backdune lakes and/or swamps.

Other physical elements that characterize the coastline are represented by channel incisions and erosional gullies, produced by running waters on the carbonate deposits.

5.2. GEOLOGY AND TECTONICS

The morphological features of the Salento Peninsula are the result of the action of a number of processes that took place from the end of Cretaceous beginning of Mesozoic, when, as an effect of the collision between tha African and the Euro-Asiatic plates, the partial emergence of the Apulian carbonate platform took place. During this phase, and the following tectonic phases, the ridges characterizing the landscape, locally known as Serre, corresponded to structural highs, that is to highplains of carbonate nature which, during the periods of repeated submersion that interested the area, remained out of the sea: they represented therefore islands, whilst in the nearby basins other sediments of carbonate origin were deposited.

Such depositional phases, related to cycles of marine ingression-regression due to eustatic movements of the sea level, brought to the formation of deposits as the Castro Limestone and the Pietra Leccese, which lithological varieties have been widely used for centuries by the local construction industry.

Further sedimentary phases, associated to local submergences of the Apulian Platform, are related to the uplift of the Apenninc Chain on one side, and of the Dinaric-Hellenic Chains on the other, starting from Middle Miocene and the beginning of the Lower Pliocene and the Quaternary.

The final emergence of the area (as well as of the whole peri-mediterranean area) during the Middle-Upper Pleistocene was accompanied by da repeated sea level changes associated to the Pleistocene-Holocene glaciations (glacial eustasy). Such oscillations of



the sea level modelled a coastal landscape in steps, well visible along the Otranto-Leuca coastline, with scarps and intervening platforms of marine abrasion, that testify the successive lowstands of the sea level, until reaching the present one.

Other typical forms of the Salento landscape are related to karst: the prevailing landform is represented by dolines, typically of circular shape, and that create depressions more or less deep with respect to the surrounding land (maximum depth about 10 meters). These karst landforms indicate time of emergence of the area (periods of continentality) with climates ranging from warm-humid to cold-temperate. The more ancient dolines, generally funnel-shaped, involve the Cretaceous carbonate formations, and show terra rossa and bauxite fillings, marsh deposits and interlayering of lignite; the younger dolines are widely diffuse over the Upper Pleistocene calcarenites.

The subterranean karst landforms are represented by caves and cave systems with variable development, mostly located along the coast, or partly flooded, and in some cases with presence of secondary deposits (stalactites, stalagmites, etc.). Remains of human skeletons and bones have been found in the stratified deposits present in some caves.

6. GLOSSARY

Abrasion: the mechanical wearing, grinding, scraping, or rubbing away (or down) of rock surfaces by friction and impact, in which the solid rock particles transported by wind, ice, waves, running water, or gravity are the tools of abrasion. The term corrasion is essentially synonymous.

Angular unconformity: an unconformity between two groups of rocks whose bedding planes are not parallel or in which the older, underlying rocks dip at a different angle (usually steeper) than the younger, overlying strata; specifically, an unconformity in which younger sediments rest upon the eroded surface of tilted or folded older rocks.

Aphotic zone: that part of the ocean in which there is not enough penetration of light for photosynthesis.

Back reef: the landward side of a reef, including the area and the contained deposits between the reef and the mainland.

Bauxite: rock composed of a mixture of various amorphous or crystalline hydrous aluminum oxides and aluminum hydroxides. It is a common residual or transported constituent of clay deposits in tropical and subtropical regions, and occurs in concretionary, compact, pisolitic, or oolitic forms. Bauxite is the principal commercial source of aluminum. Named after Les Baux de Provence, a locality near Arles in southern France.

Benthos: those forms of marine life that are bottom-dwelling; also, the ocean bottom itself. Adjective: benthic, benthonic.

Berm: a low, impermanent, nearly horizontal or landward-sloping bench, shelf, ledge, or narrow terrace on the backshore of a beach, formed of material thrown up and deposited by storm waves.

Biomicrite: a limestone consisting of a variable proportion of skeletal debris and carbonate mud (micrite).

Bioturbation: reworking of soils or sediments by animals and plants.



Calcarenite: a limestone consisting predominantly of recycled calcite particles of sand size; a consolidated calcareous sand.

Clino-stratification: inclined bedding of strata, related to environment of sedimentation that lies on the sloping part of the floor of a water body.

Connate water (fossil water): water entrapped in the interstices of a sedimentary rock at the time of its deposition.

Corrosion: a process of erosion wherby rocks and soil are removed or worn away by natural chemical processes, especially by the solvent action of running water, but also by other reactions such as hydrolysis, hydration, carbonation, and oxidation.

Disconformity: an unconformity in which the bedding planes above and below the break are essentially parallel, indicating a significant interruption in the orderly sequence of sedimentary rocks, generally by a considerable interval of erosion (or sometimes of nondeposition), and usually marked by a visible and irregular or uneven erosion surface of appreciable relief.

Doline (sinkhole): a circular depression in a karst area. Its drainage is subterranean, its size is measured in meters or tens of meters, and it is commonly funnel-shaped.

Epicenter: the point on the Earths surface that is directly above the focus (initial rupture point) of an earthquake.

Euphotic zone: that part of the ocean in which there is sufficient penetration of light to support photosynthesis. The depth varies, but averages about 80 m.

Eustatism (eustasy): the worldwide sea-level regime and its fluctuations, caused by absolute changes in the quantity of seawater, e.g. by continental icecap fluctuations (glacio-eustasy).

Foraminifer: any protozoan belonging to the subclass Sarcodina, order Foraminifera, characterized y the presence of a test of one to many chambers composed of secreted calcite or of agglutinated particles. Most foraminifers are marine but freshwater forms are known. Range, Cambrian to present.

Fore reef: the seaward side of a reef; in places a steep slope covered with deposits of reef talus, elsewhere an organism-constructed vertical wall.

Glauconite: name applied to a group of minerals consisting of hydrous silicates of potassium and iron.

Karst: a type of topography that is formed on limestone, gypsum, and other rocks by dissolution, and that is characterized by sinkholes, caves, and underground drainage.

Ittiodontoliti: fossilized fish teeth.

Lepidocycline: Foraminifera genus.

Lithophagous: said of an organism that feeds on rock material.

Marl: a rock formed as a mixture of clay and calcium carbonate, under marine or freshwater conditions.

Nummulite: any foraminifer belonging to the family Nummulitidae. Range, Upper Cretaceous to present.

Neritic: pertaining to the ocean environment or depth zone between low-tide level and 100 fathoms, or between low-tide level and approximately the edge of the continental shelf; also, pertaining to the organisms living in that environment. Also called the sublittoral zone.

Oligo-: a prefix meaning small, a little.

Permeability: the property or capacity of a porous rock, sediment, or soil for transmitting a fluid.

Phosphatization: the conversion of something into a phosphate.

Phreatic water: a term that originally was applied only to water that occurs in the upper part of the zone of saturation under water-table conditions, but has come to be applied to all water in the zone of saturation, thus making it an exact synonymous of groundwater.



Pisolite: a sedimentary rock, usually a limestone, made up chiefly of pisoliths cemented together.

Pisolith: one of the small, round or ellipsoidal accretionary bodies in a sedimentary rock, resembling a pea in size and shape. It is often formed of calcium carbonate. A pisolith is larger than an oolith, although it has the same concentric and radial internal structure. The term is sometimes used to refer to the rock made up of pisoliths.

Platform: a general term for any level or nearly level surface.

Reef: a ridgelike or moundlike structure, layered or massive, built by sedentary calcareous organisms, especially corals, and consisting mostly of their remains; it is wave-resistant and stands above he surrounding contemporaneously deposited sediment.

Reef front: the upper part of the outer or seaward slope of a reef, extending to the reef edge from above the depth limit of abundant living coral and coralline algae.

Residual deposit: the residue formed by weathering in place.

Rhodolith: a nodule of red (coralline) algae, concentrically encrusted, often rolled by bottom currents.

Rudist: any bivalve mollusk belonging to the superfamily Hippuritacea, characterized by an inequivalve shell, usually attached to a substrate, and either solitary or gregarious in reeflike masses. They are frequently found in association with corals. Range, Upper Jurassic to Upper Cretaceous, possibly Paleocene.

Sulfur water: generally, water containing enough hydrogen sulfide to smell and taste. Except for the hydrogen sulfide, it may not differ in mineral content from ordinary potable water, or it may qualify as saline water.

Swallow hole (swallet): a closed depression or doline into which all or part of a stream disappears underground.

Taxon (pl. Taxa): a named group of organisms of any rank, such as a particular species, family, or class. A taxon may be designated by a formal Latin name or by a letter, number, or other symbol.

Tsunami: a gravitational sea wave produced by any large-scale, short-duration disturbance of the ocean floor, principally by a shallow submarine earthquake, but also by submarine earth movement, subsidence, or volcanic eruption. It is characterized by high speed of propagation (up to 950 km/hr), long wavelength (up to 200 km), long period (varying from 5 min to a few hours), and low observable amplitude on the open sea. Etymol.: from the Japanese, harbor wave.

Type locality: the locality where a particular rock type, stratigraphic unit, fossil or mineral species is first identified.

Unconformity: a substantial break or gap in the geological record where a rock unit is overlain by another that is not next in stratigraphic succession, such as an interruption in the continuity of a depositional sequence of sedimentary rocks or a break between eroded igneous rocks and younger sedimentary strata.

Geotouristic Itinerary in Apulia - Guide

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