0000000000463425
AUTHOR
Giuliana Madonia
showing 78 related works from this author
Preliminary considerations on the monitoring of meteorological and environmental parameters in the Natural Reserves "Grotta di Santa Ninfa" and "Grot…
2009
Evoluzione geomorfologica della Sicilia occidentale
2014
Capturing gypsum rillenkarren morphometry by a 3D-photo reconstruction (3D-PR) technique
2020
Abstract Rillenkarren are small scale, straight, narrow solution channels that head at the crest of a bare rock slope and are extinguished downslope. In this paper the applicability of 3D-photo reconstruction technique of the rock surface is proposed for capturing the rillenkarren morphometry on gypsum. At first, the measurements are used to assess a relationship between the width/depth ratio and the depth of the rillenkarren. The exponent of this power relationship resulted different from the theoretical value - 0.5, confirming that the cross-section profiles of a rillenkarren can have a shape different from parabolic. The analysis developed for the cross-section area, the perimeter and th…
New insights on the Carburangeli Cave speleogenesis: a flank margin cave in Northern Sicily (Italy)
2022
Flank margin caves form in coastal regions by mixing dissolution. Their development is controlled by the position of the freshsalt water mixing boundary, which in turn, is related to sea-level position. They are characterized by a typical cave pattern and cave-wall morphologies and represent good indicators of past sea levels. This contribution shows the results of recent studies conducted in the Carburangeli Cave, a small sub-horizontal cavity developed in Northern Sicily, close to Palermo. This cave was firstly known for paleontological and archaeological findings and for these reasons, along with its speleological and biological interest, a Nature Reserve has been instituted by the Sicil…
Il carsismo nei rilievi carbonatici della Sicilia Nordoccidentale.
2007
New insights on secondary minerals from Italian sulfuric acid caves
2018
Sulfuric acid minerals are important clues to identify the speleogenetic phases of hypogene caves. Italy hosts ~25% of the known worldwide sulfuric acid speleogenetic (SAS) systems, including the famous well-studied Frasassi, Monte Cucco, and Acquasanta Terme caves. Nevertheless, other underground environments have been analyzed, and interesting mineralogical assemblages were found associated with peculiar geomorphological features such as cupolas, replacement pockets, feeders, sulfuric notches, and sub-horizontal levels. In this paper, we focused on 15 cave systems located along the Apennine Chain, in Apulia, in Sicily, and in Sardinia, where copious SAS minerals were observed. Some of the…
Gypsum karst systems of southern-central Sicily (southern Italy) as powerful markers in geomorphological studies
2011
Deep-seated gravitational slope deformations in western Sicily: Controlling factors, triggering mechanisms, and morphoevolutionary models
2014
Abstract A study of deep-seated gravitational slope deformation (DSGSD) phenomena affecting areas of various geological and geomorphological settings in western Sicily is described. Western Sicily is underlain by a thin-skinned imbricate wedge of Meso–Cenozoic carbonate and siliciclastic rocks that formed by the stacking of several thrust nappes over the Iblean foreland. Locally, the original thrust sheets are folded and cut by high-angle faults. Large areas of western Sicily now display high relief energy due to Plio-Pleistocene block-faulting and uplifting, and the Quaternary morphogenetic phases are characterised by incision, thereby triggering widespread DSGSDs. To identify controlling …
Examples of anthropogenic sinkholes in Sicily and comparison with similar phenomena in southern Italy
2013
A sinkhole, occurred in June 2011 and related to an underground quarry in the eastern sector of Marsala, is described in this paper as a case study (Figure 2). The site was selected for the availability of topographic data of the underground quarry, prior to the formation of the Abstract Anthropogenic sinkholes affect several built-up areas of Sicily (southern Italy) representing a great risk to people, buildings, and infrastructures. These phenomena are generally associated with the presence of ancient underground quarries for the extraction of calcarenite rock, used for building or ornamental materials. These quarries were poorly constructed and abandoned throughout history.
The great polje-like depressions in Sicily
2009
A three-dimensional back-analysis of the collapse of an underground cavity in soft rocks
2017
Abstract The assessment of stability of man-made underground caves, excavated in the past and later on abandoned, represents a serious challenge for land and urban planning operations, especially for the areas of possible interaction of the caves with overlying structures and infrastructures. Several areas of Southern Italy are characterized by the presence of abandoned underground quarries for the extraction of soft calcarenite rocks, which now threatens the overlying environment due to the risk of collapse and the consequent generation of sinkholes. This work presents a back-analysis of a sinkhole occurred in 2011 in the town of Marsala, caused by the collapse of an underground quarry, as…
THE KARREN LANDSCAPES IN THE EVAPORITIC ROCKS OF SICILY.
2009
The karren in the evaporitic rocks of Sicily show wide distribution and variety of shapes relating to the large extension of the rocky outcrops, to the different lithofacies and to the climate. Karren features are largely present in all kinds of evaporites: macrocrystalline selenitic gypsum, detritic gypsum with various grain size, microcrystalline gypsum and in salts such as halite and kainite. Both the origin and the evolution of the karren are controlled by the dynamics of several processes such as solution and recrystallization, granular disintegration, carbonation, and phenomena linked to biological activity. The karren features have different dimensions, ranging from the nano- and the…
Il qanat di Villa Riso (Palermo, Sicilia)
2020
Durante i lavori di ristrutturazione del complesso edilizio di Villa Riso, villa storica ubicata nell’area della Piana dei Colli (Palermo), sono state applicate tecniche di prospezione georadar e di ispezione diretta che hanno permesso di rinvenire un cunicolo drenante di tipo qanat nel sottosuolo della corte antistante la villa. La presenza di cunicoli drenanti al di sotto di antiche ville è frequente in questo settore della città di Palermo, ma la possibilità di accedervi diventa sempre più difficoltosa, a causa del loro cattivo stato di conservazione. Il qanat di Villa Riso presenta la classica struttura dei qanat della Piana dei Colli, dai quali, tuttavia, si differenzia per la presenza…
Solution and recrystallisation processes and associated landforms in gypsum outcrops of Sicily
2003
Abstract Four small areas of Messinian (Upper Miocene) age gypsum, outcropping in western Sicily, are described. Messinian age evaporites are found in Sicily over a 1000-km 2 area. Here, gypsum outcrops extensively as a consequence of soil erosion induced by human impact. Geomorphological maps show how the rocky surfaces are characterized by a wide range of forms. There are large, medium, small, and microsized forms, which can be identified as belonging to different morphotypes. The morphotypes can be classified into two main categories: those that originated by solution and those that originated through recrystallisation. Four areas, illustrated by geomorphological maps, were specifically …
Holocene climate variability in Sicily from a discontinuous stalagmite record and the Mesolithic to Neolithic transition
2006
AbstractFabric and stable isotopic composition of a Holocene stalagmite (CR1) from a cave in northern Sicily record changes in paleorainfall in the early Holocene. High δ13C stable isotope values in the calcite deposited from ca. 8500 to ca. 7500 yr ago are interpreted as reflecting periods of high rainfall. The wet phase was interrupted by two periods of multi-century duration characterized by relatively cool and dry winters centered at ca. 8200 and ca. 7500 yr ago, highlighted by low δ13C and δ18O values. A high variability of δ13C values is recorded from ca. 7500 to ca. 6500 yr ago and indicates that the transition from a pluvial early Holocene to the present-day climate conditions was p…
The Santa Ninfa Cave (Belice Valley): hydrogeochemical features and relationships with neotectonics
2020
The Santa Ninfa Cave (SNC) develops in an outcrop of Messinian gypsum, located in the heart of the zone struck by the 1968 seismic sequence of the Belice valley. It is composed of different levels of sub-horizontal galleries, the lowest of which is characterized by perennial flowing water, running along the water table. From the hydrogeological point of view, it configures as an open circuit, both inflowing and outflowing from/to neighboring aquifers. The geochemical facies of groundwater collected in the SNC is compatible with a meteoric recharge chemically interacting with evaporitic deposits. The most relevant geochemical feature is the mixing between a small tributary of sulfur water wi…
First report on the sinkhole phenomena in the Sicilian evaporites (Southern Italy)
2009
Caves in the Belmonte Mezzagno area (North-West Sicily)
2010
An Overview of the Hypogene Caves of Sicily
2017
Karst in Sicily develops in both Messinian gypsum and Mesozoic or Tertiary limestone rocks. Caves are also found in the basalts of Mount Etna. Except for some rare cases, until recently most caves developed in limestone were considered to be of epigenetic origin. The discovery of gypsum in some of these caves, and especially detailed morphological studies, have allowed defining a hypogenic origin for a dozen of caves up to now. In some of these, the hypogenic evidences are very clear, while others remain in doubt because of the widespread presence of well-developed condensation-corrosion morphologies not necessarily related to hydrothermal fluids. This paper reports the present knowledge of…
Il sistema carsico di Monte Conca
2014
The Madonie Geopark (Italy): geological and geomorphological features
2004
Analisi numerica dei processi di instabilità in cave sotterranee a Marsala (Sicilia occidentale)
2014
La presenza di estesi sistemi caveali in sotterraneo, utilizzati nel secolo scorso per l’estrazione di materiale da costruzione in diversi contesti del territorio italiano, di frequente determina situazioni di pericolo per l’ambiente antropizzato, a causa dello sviluppo di processi di instabilità, che possono propagarsi verso l’alto, sino a raggiungere la superficie. Specialmente nei casi in cui la memoria storica della presenza ed estensione delle cave sotterranee è andata persa, lo sviluppo urbanistico dei centri abitati nel corso degli ultimi decenni può avere determinato la realizzazione di abitazioni ed infrastrutture al di sopra, o nelle immediate vicinanze, di zone interessate da com…
Aspetti geologici e geomorflogici dell'area di Pizzo Chiarastella (Sicilia settentrionale)
2004
Morphometric analysis of dolines in the Carbonara Massif (Madonie Mountains - Northern Central Sicily).
2009
Gypsum caves in Sicily (Italy)
2005
Caves in the Belmonte Mezzagno area (PA).
2009
First study of gypsum karst in Sicily. The contribution of Olinto Marinelli and Mariano Gemmellaro
2006
KARST OF SICILY AND ITS CONSERVATION
2012
Evaporite karst in Italy: A review
2017
none 16 si Although outcropping rarely in Italy, evaporite (gypsum and anhydrite) karst has been described in detail since the early 20th century. Gypsum caves are now known from almost all Italian regions, but are mainly localised along the northern border of the Apennine chain (Emilia Romagna and Marche), Calabria, and Sicily, where the major outcrops occur. Recently, important caves have also been discovered in the underground gypsum mines in Piedmont. During the late 80s and 90s several multidisciplinary studies were carried out in many gypsum areas, resulting in a comprehensive overview, promoting further research in these special karst regions. More recent and detailed studies focused…
Gypsum karst in Sicily (Italy)
2005
Relazioni tra grotte nei gessi e forme del rilievo di superficie: un modello morfoevolutivo di un'area carsica della Sicilia centro-meridionale
2008
Evaporites in Sicily: geological and karst features
2012
Hydrological changes in NW Sicily from a discontinuous Holocene stalagmite record
2006
Ambiente e clima della Sicilia durante gli ultimi 20 mila anni
2010
Environment and Climate in Sicily over the last 20, 000 years. (IT ISSN 0394-3356, 2010). A series of recent studies shed light on the central Mediterranean, and Sicily, climate and environment, starting from the last glacial maximum (about 20 ka cal BP). In the present paper, we examine most of these works, in order to unravel environmental changes of the past, mainly in terms of temperature, atmospheric pattern, precipitation, vegetation and faunal associations. The climate of the last glacial maximum was characterised by very low temperature and by repeated northerlies penetration, even during summer. Low precipitation values led to a steppe- or semisteppe-like vegetation pattern, domina…
L’ultimo sprofondamento a Marsala: l’evento del 21 novembre 2013
2015
The Marsala area, at the western end of Sicily, has been historically interested by quarry activities, both at surface and underground. The carved rocks are Lower Pleistocene calcarenites, defined as “Calcarenite di Marsala” and referred to the Marsala syntheme. The subterranean quarries, now abandoned, show increasing instability signs becoming in time a risk factor for several causes, among which: a) breakdowns due to poor (weak) strength of rock and to large size of voids; b) progressive weathering of rock; c) effects of the discontinuities in the rock mass with the pillars and/or walls of the underground quarries. These factors contributed to enlargement of the subterranean voids and to…
1. Inquadramento geologico e geomorfologico
2021
Vengono descritti i caratteri geologici e geomorfologici del territorio comunale di Contessa Entellina (PA), i cui risultati sono sintetizzati in una carta geologica, una carta geomorfologica e una carta litologica.
La Grotta dei Personaggi di Montevago (AG), una nuova segnalazione di cavità ipogenica in Sicilia
2015
La Grotta dei Personaggi è localizzata in Sicilia occidentale, nei pressi di Monte Magaggiaro, a S del centro abitato di Montevago (AG). Nell’area sono presenti sorgenti termali, caratterizzate da acque cloro-solfate alcalino-terrose con temperatura di circa 40 °C e pH 7. La Grotta dei Personaggi, conosciuta già dai primi anni del 1900 e nota anche per ritrovamenti archeologici, non era mai stata dettagliatamente rilevata e studiata. La cavità si sviluppa prevalentemente in calcari di piattaforma della formazione Inici (Giurassico inf.) e in calcari di scarpata e pelagici della formazione Buccheri (Giurassico inf.-sup.). Si tratta di una cavità sub-orizzontale che presenta uno sviluppo di c…
An example of geological path in the Madonie Park (Sicily): the geological path n. 1 “Inghiottitoio della Battaglietta – Portella Colla”.
2005
La Geomorfologia
2004
I fenomeni carsici in Sicilia
2008
I primi studi sul carsismo nei gessi della Sicilia. Il contributo di Olinto Marinelli e di Mariano Gemmellaro
2004
I. 1. Inquadramento geologico
2015
Vengono illustrati brevemente i caratteri geologici e geomorfologici della Sicilia occidentale e analizzate le relazioni tra antichi insediamenti e geologia.
New Knowledge on the Monte Conca gypsum karst system (Central-Western Sicily).
2009
Schema geomorfologico della Penisola di Capo San Vito (Sicilia nord-occidentale)
2004
New knowledge on the Monte Conca gypsum karst system (Central-western Sicily, Italy)
2011
The Monte Conca karst system is located in Central-Western Sicily, where Messinian evaporites are widespread. Here, the evaporites lie on lower Messinian-middle Serravallian clayey-marly-sandy deposits and are overlain locally by Pliocene marly limestones. These successions are affected by E-W, and to a lesser degree N-S and NW-SE, high-angle faults that have also produced lateral contacts between the gypsum units and the clayey-marly deposits. The cave passages reachaltogether about 2.4 km in lengthand 130 m in depth, and the system consists of a sink cave, a resurgence and a relict resurgence. At large scale it is characterized by superimposed levels of sub-horizontal galleries connected …
Secondary Minerals From Italian Sulfuric Acid Caves
2017
Italy is a country hosting a large number of hypogenic sulfuric acid (SAS) speleogenesis caves, mostly located along the Apennine chain, but also in Campania (along the coastline of Capo Palinuro), Apulia (along the coastline of Santa Cesarea Terme) and Sicily. Besides the typical morphologies related to their special geochemical origin (cupolas, replacement pockets, bubble trails, etc), these caves often host abundant secondary mineral deposits, mainly gypsum, being the result of the interaction between the sulfuric acid and the carbonate host rock. Native sulfur deposits are also well visible on the ceiling and roof, and peculiar sulfuric acid minerals such as jarosite, alunite, and other…
KARST LANDSCAPES IN SICILY (SOUTHERN ITALY), WITH EXAMPLES OF SUSTAINABLE EXPLOITATION
2010
Study of anthropogenic sinkholes in the Marsala area (western Sicily) through numerical analyses of instability processes in underground quarries
2011
Analisi numerica dei processi di instabilità in cave sotterranee
2014
La presenza di estesi sistemi caveali in sotterraneo, utilizzati nel secolo scorso per l’estrazione di materiale da costruzione in diversi contesti del territorio italiano, di frequente determina situazioni di pericolo per l’ambiente antropizzato, a causa dello sviluppo di processi di instabilità, che possono propagarsi verso l’alto, sino a raggiungere la superficie. Specialmente nei casi in cui la memoria storica della presenza ed estensione delle cave sotterranee è andata persa, lo sviluppo urbanistico dei centri abitati nel corso degli ultimi decenni può avere determinato la realizzazione di abitazioni ed infrastrutture al di sopra, o nelle immediate vicinanze, di zone interessate da com…
Percorsi didattico-naturalistici tra paesaggi carsici nelle evaporiti della Sicilia
2004
Il carsismo nei rilievi carbonatici della Sicilia nord occidentale (Carbonate Karst in the NW Sicily)
2004
L'impact méconnu des chauves-souris et du guano dans l'évolution morphologique tardive des cavernes
2016
The little known impact of bats and bat guano in the late stages of cave morphogenesis. Bats are considered as symbolic caves inhabitants. The colonies, sometimes huge, may occupy caves through long periods. Large guano deposits were accumulated. Some have been mined for phosphates, either by hand or at the industrial scale. Bats impact is triple: breathing releases CO2, urine is corrosive, and guano mineralization releases acids (carbonic, nitric, sulfuric, and phosphoric). Such aggressive compounds have an effect on carbonate rock and flowstones, either by direct ground corrosion at the contact of the guano, or by condensation-corrosion on walls and ceilings. The speleogenetic impact of t…
La Grotta di Carburangeli – ricostruzione climatica dell’Olocene per la piana costiera della Sicilia nord-occidentale
2005
Detection of Quaternary tectonic deformations through quantitative morphotectonic analysis in a drainage basin of northern Sicily (Italy)
2012
Sulfuric acid water table caves (Grotte du Chat / Acqua Fitusa /Bad Deutsch Altenburg + Kraushöhle).
2014
Sulfuric acid caves can display a variety of forms, from 3D maze systems, to isolated chambers, and more or less maze-like water table caves. Most of the voids are normally generated at or immediately above the water table, where condensation-corrosion processes are dominant, creating a set of characteristic meso- and micromorphologies. This paper deals with the description of four very typical sulfuric acid water table caves: the Grotte du Chat in Provence (France), the Acqua Fitusa Cave in Sicily (Italy), and the Bad Deutsch Altenburg and Kraushöhle caves in Austria.
Geological Path n.1.
2004
Sprofondamenti di origine antropica nell'area di Marsala (Sicilia occidentale) analizzati mediante rilievi in sito e analisi numerica dei processi di…
2013
Geomorphological setting of Madonie Geopark (Italy)
2006
The Madonie Natural Park is characterized by relevant zoological and botanic aspects and by geological features so remarkable that since 2001 it has been incorporated into the European Geoparks Network. The Park is marked by a wide massif know as Madonie Mountains. In this area, segment of the Maghrebide-Apenninic chain, successions of Meso-Cenozoic lithologies and late- and post-orogenic deposits occur. The geomorphological setting is extremely varied and includes many landscapes characterising several Sicilian areas; it results from the interaction between geomorphological processes, tectonic movements and climatic changes. It is possible to identify five distinct sectors, each correspond…
Gypsum karst caves versus surface landforms to define a morphoevolutive model in Central Southern Sicily (Southern Italy)
2005
Il sistema carsico Vallone Ponte - Grotte d'Acqua
2012
Anthropogenic sinkholes in central-south Sicily
2013
Meccanismi di innesco dei fenomeni di espandimento laterale nei rilievi montuosi della Sicilia occidentale: i casi di Monte Speziale e Rocca Busambra
2011
The Madonie Park geological guide
2004
Primi risultati su alcune grotte ipogeniche della Sicilia
2012
Vengono presentati i risultati preliminari di uno studio condotto su alcune grotte ipogeniche della Sicilia, ritenute fino a questo momento di natura epigenica: il sistema carsico di Monte Inici e la Grotta dell’Acqua Fitusa. Il primo sistema è localizzato nella Sicilia nordoccidentale lungo il versante sudorientale di Monte Inici. È costituito da due cavità, la Grotta dell’Eremita e l’Abisso dei Cocci, che si sviluppano in calcari e calcari dolomitici della Fm. Inici (Giura inf.) e in calcari ad ammoniti della Fm. Buccheri (Giura medio-sup.). Si tratta di sistemi tridimensionali freatici che raggiungono una lunghezza di oltre 2km e una profondità superiore a 300m. Sono caratterizzati da di…
Recenti indagini sul sistema carsico di Sant’Angelo Muxaro (Sicilia Centrale)
2015
Il sistema carsico di Sant’Angelo Muxaro si sviluppa in corrispondenza del rilievo gessoso su cui sorge l’abitato omonimo, nel centro Sicilia, in provincia di Agrigento. Tale sistema è costituito da due inghiottitoi attivi (Grotta di Sant’Angelo Muxaro o localmente Grotta Ciavuli e Inghiottitoio Infantino), che si aprono al termine di due valli cieche alla base del versante meridionale del rilievo, e da una risorgenza attiva, ubicata alle pendici del versante nord-occidentale dello stesso rilievo. Le prime esplorazioni speleologiche e l’attività di ricerca in questo sistema nei gessi messiniani della Sicilia, escludendo le segnalazioni del geografo Olinto Marinelli, sono cominciate tra la f…
Aspetti geologici e geomorfologici dell'area di Pizzo Chiarastella (Sicilia settentrionale)
2007
Geomorphological evolution of western Sicily, Italy
2017
Abstract This paper proposes a morphoevolutionary model for western Sicily. Sicily is a chain–foredeep–foreland system still being built, with tectonic activity involving uplift which tends to create new relief. To reconstruct the morphoevolutionary model, geological, and geomorphological studies were done on the basis of field survey and aerial photographic interpretation. The collected data show large areas characterized by specific geological, geomorphological, and topographical settings with rocks, landforms, and landscapes progressively older from south to north Sicily. The achieved results display: (1) gradual emersion of new areas due to uplift, its interaction with the Quaternary gl…
GUIDA GEOLOGICA DEL PARCO DELLE MADONIE
2004
Peculiar wall channels connected to fault breccia in the Grotta di Entella gypsum cave (Western Sicily, Italy)
2010
Sulfuric acid speleogenesis (SAS) close to the water table: Examples from southern France, Austria, and Sicily
2016
Caves formed by rising sulfuric waters have been described from all over the world in a wide variety of climate settings, from arid regions to mid-latitude and alpine areas. H2S is generally formed at depth by reduction of sulfates in the presence of hydrocarbons and is transported in solution through the deep aquifers. In tectonically disturbed areas major fractures eventually allow these H2S-bearing fluids to rise to the surface where oxidation processes can become active producing sulfuric acid. This extremely strong acid reacts with the carbonate bedrock creating caves, some of which are among the largest and most spectacular in the world. Production of sulfuric acid mostly occurs at or…
Guano-related phosphate-rich minerals in European caves
2019
International audience; Guano is a typical deposit found in caves derived from the excretions of bats and in minor cases of birds. These organic deposits decompose and form a series of acid fluids and gases that can interact with the minerals, sediments, and rocks present in the cave. Over sixty phosphates are known and described from caves, but guano decay also often leads to the formation of nitrates and sulfates. In this study twenty-two European caves were investigated for their guano-related secondary minerals. Using various analytical techniques, seventeen phosphates, along with one sulfate (gypsum), were recognized as secondary products of guano decay. Among those minerals, some are …
ASPETTI GEOLOGICI, GEOMORFOLOGICI E ANTROPOLOGICI DE LA MONTAGNOLA (SAN GIOVANNI GEMINI, AGRIGENTO): PROPOSTA DI UN GEOSITO
2014
A review on hypogene caves in Italy
2014
Although hypogene cave systems have been described since the beginning of the 20th century, the importance in speleogenesis of ascending fluids that acquired their aggressiveness from in-depth sources has been fully realized only in the last decades. Aggressiveness of waters can be related to carbonic and sulfuric acids and the related corrosion-dissolution processes give rise to different types of caves and underground morphologies. The abundance of hydrothermal springs and associated travertine deposits, and the widespread interaction between volcanic or sub-volcanic phenomena and karst in many sectors of the Italian peninsula are a strong evidence of hypogene speleogenesis. Furthermore, …
Anthropogenic sinkholes in the Marsala area (western Sicily) linked to underground quarries
2012
Sulfuric Acid Caves of Italy: An Overview
2016
Sulfuric acid caves of Italy: A review
2019
Abstract In Italy, especially along the Apennine Chain, numerous active and inactive sulfuric acid speleogenetic (SAS) caves have been documented in the last two decades. Here we present an overview of these peculiar hypogene systems, illustrating their main geomorphological and mineralogical features, and the microbial signatures observed in the active underground environment. SAS caves are widely distributed in the northern and central Apennines, whereas they are less abundant in the southern Apennines, in the Apulian foreland, in Sicily and in Sardinia. Their location is significantly influenced by lithological and structural rock properties, as they occur in carbonate areas where acidic…