Lower- to Middle Pleistocene flank margin caves at Custonaci (Trapani, NW Sicily) and their relation with past sea levels

The peninsula of San Vito Lo Capo, 50 km West of Palermo (Sicily), is characterised by the presence of a wide set of evidences of past sea level changes, such as marine terraces, notches, marine and coastal caves with phreatic overgrowths on speleothems, and continental and marine deposits. The exceptional good preservation of these landforms and deposits has been used by different authors for the reconstruction of sea level changes and neotectonic movements. Among the many caves discussed by previous authors, most are of marine origin and can preserve signs of old sea level highstands such as notches and marine or continental sediments. However, two caves in particular, Fantasma Cave and Falesia Rocca Rumena I cave, show evidences to be flank margin caves. Both caves are records of rising and falling sea level, and their position and the correlation with marine terraces suggest them to be around 0.8 and 1.1–1.2 Ma old respectively. This study shows that not all sea level high stands are preserved in the stratigraphical and geomorphological record.Keywords: telogenetic limestones, coastal karst, mixing zone speleogenesis, sea level changes, Quaternary

The ribbed drapery of the Puerto Princesa Underground River (Palawan, Philippines): morphology and genesis

During the 2011 speleological expedition to the Puerto Princesa Underground River (Palawan, Philippines) a drapery characterized by several close-to-horizontal ribs has been noticed. Even without sampling and analyzing its internal growth layers, a detailed morphological study allowed to present a possible genetic model. The presented model helps to explain its evolution, which is mainly controlled by variation in water flow as a consequence of the Palawan climate. When validated by further analyses, the same genetic mechanism could define also the evolution of the very common but still unexplained complex flowstones, which exhibit several close-to-horizontal steps, widenings and narrowings along their growth axis

geomorphologic evolution of a coastal karst the gulf of orosei central east sardinia italy

Orosejski zaliv je eno najpomembnejsih obalnokraskih obmocij v Italiji. Stevilne nove meritve jam so omogocile boljse razumevanje speleogeneze na obmocju zaliva. Razvoj krasa na tem obmocju smo raziskovali z razlicnimi geomorfoloskimi raziskavami na povrsju in pod morjem, ter speloloskimi raziskavami v jamah. Glavni faktorji morfoloskih procesov so litologija, tektonika, paleoklima in nihanja morske gladine. Studija nekaterih pomembnih jamskih sistemov je pokazala kompleksen geoloski razvoj, kjer so kraski procesi igrali pomembno vlogo od zgodnjega terciarja in dosegli visek v pliokvartarju. In the past ten years cave surveying has allowed better understanding of speleogenesis in the Orosei Gulf (Central-East Sardinia, Italy), one of the most important coastal karst areas of Italy. Surface geomorphologic research has been accompanied by subterranean and submarine landform analysis in order to try and understand the evolution of this coastal karst since its emersion in Upper Eocene. The main factors influencing the geomorphic processes are lithology, tectonics, palaeo-climate and sea level changes. The study of several important cave systems demonstrates a complex geological history with karst processes that started in Early Tertiary and accelerated during Plio-Quaternary

Secondary minerals in minothems at Fragnè Mine (Turin, Italy)

The Fragnè mine, Chialamberto (TO), is located in the Lanzo valley. The study area is part of the structural complex historically indicated as "area of calcschists and greenstones" or "Piedmont area" formed by mesozoic ophiolitic units of the Piedmontese Ligurian Basin by the tectonic-metamorphic evolution related to the alpine orogenesis (Falletti et al., 2009). The mineralizations are characterized by massive pyrite and Cu-rich pyrite that occurs in greenschist (prasinite) and amphibolite schist. The underground works development is around 5 km, tunnels that branch off into different levels. In this work, we describe secondary minerals of minothems (Carbone et al., 2016) not yet described in the Fragnè mine and found usually inside natural caves characterized by different mineralogical associations. The results show that all samples are characterized by secondary Fe-rich minerals typical of acid mine drainage areas. Blisters are composed only by schwertmannite, war-clubs by schwertmannite and goethite with low crystallinity, and hair by epsomite and hexahydrite minerals. Jelly stalactites and jelly stalagmites are characterized by schwertmannite in association with bacterial masses, instead stalactites and stalagmites by jarosite and goethite. The results shows that a mineralogical transformation occurs from soft to hard minothems: schwertmannite tends to transform into goethite, probably due to ageing processes of schwertmannite or local pH variations, related to bacterial activity, since schwertmannite is a metastable phase which over time tends to turn into goethite (Jönsson et al., 2005)

Ricostruzione paleoclimatica attraverso l'analisi di uno speleotema nella Sardegna centro-orientale: risultati preliminari

This paper, carried out in the framework of a local project 60% «Pleistocene-Holocene palaeoclimate and palaeogeography reconstructions based on marine and continental deposits of Sardinia» (Resp. Prof. Sandro De Muro) and within a series of researches involving several bodies (Archaeological Superintendence of NU/SS, Universities of Parma and Cagliari) and caving associations (Gruppo Speleo Ambientale Sassari, Gruppo Speleo-Archeologico Giovanni Spano of Cagliari, Unione Speleologica Cagliaritana and Gruppo Archeo Speleo Ambientale Urzulei), reports the first results of a palaeo-climate study carried out on a stalagmite sampled in the Su Palu cave, Codula Ilune, Urzulei (Central-East Sardinia). This stalagmite has been subjected to radiometric U/Th dating and stable isotope δ180 and δ 13C analysis. These isotopic data based on 139 samples showed a general increase in stable isotope ratios that would indicate a growth of the concretion in a period of global warming (Upper Pleistocene- Holocene?). The chronological setting by means of U/Th datings, unfortunately, did not allow to define the exact timeframe because of the presence of detrital Thorium. C14 analysis are under way to try to obtain information on the time during which the stalagmite growed

On the Use of Tri-Stereo Pleiades Images for the Morphometric Measurement of Dolines in the Basaltic Plateau of Azrou (Middle Atlas, Morocco)

Hundreds of large and deep collapse dolines dot the surface of the Quaternary basaltic plateau of Azrou, in the Middle Atlas of Morocco. In the absence of detailed topographic maps, the morphometric study of such a large number of features requires the use of remote sensing techniques. We present the processing, extraction, and validation of depth measurements of 89 dolines using tri-stereo Pleiades images acquired in 2018–2019 (the European Space Agency (ESA) © CNES 2018, distributed by Airbus DS). Satellite image-derived DEMs were field-verified using traditional mapping techniques, which showed a very good agreement between field and remote sensing measures. The high resolution of these tri-stereo images allowed to automatically generate accurate morphometric datasets not only regarding the planimetric parameters of the dolines (diameters, contours, orientation of long axes), but also for what concerns their depth and altimetric profiles. Our study demonstrates the potential of using these types of images on rugged morphologies and for the measurement of steep depressions, where traditional remote sensing techniques may be hindered by shadow zones and blind portions. Tri-stereo images might also be suitable for the measurement of deep and steep depressions (skylights and collapses) on Martian and Lunar lava flows, suitable targets for future planetary cave exploration

Secondary minerals in minothem environments

Secondary minerals forming speleothems are called “cave minerals” and are the results of complex interactions between bedrock, circulating water, and sediments of various sources. A "speleothem" is a secondary mineral deposit formed in a cave by a chemical reaction from a primary mineral in bedrock or detritus because of a unique set of conditions therein. In Carbone et al. (2016) the term “minothems” was defined, for the first time, considering the secondary mineral concretions forming in an artificial underground void, such as a mine or any other kind of tunnel (i.e. roman aqueduct, catacomb, highway tunnel, etc.). These voids can be carved in carbonate rocks, but can also be hosted in different geological materials, such as volcanic rocks, ophiolites or granites. Minothems are the counterpart of speleothems in natural caves, and generally show the same morphologies. However, the petrographical and geological differences of the host rock can cause significant distinctions in mineralogy, colour and shape of the minothems respect to speleothems. In this work we describe minothems and secondary minerals forming in three abandoned sulphide mines from the Ligurian (Libiola anche Reppia mine) and Piemonte region (Fragnè mine). All studied sites are abandoned and are characterised by active and intense Acid Mine Drainage (AMD) processes triggered by the supergenic interaction between sulphide-rich mineralisations and atmospheric agents. Acid Sulfate Waters (ASW) percolating inside the galleries drip through the mine roof and form numerous decorative dripstone features that coat the walls, ceilings, and floors of the mine, and grow out of muck piles creating a colourful array of white, yellow, orange, green, blue, brown and black minothems. Mine adits host soda straws, stalactites, draperies, stalagmites, columns, flowstones, gours, but can also contain pearls, rafts, coralloids (popcorn), moonmilk, and helictites. These are often composed of exotic minerals, mainly sulphates (melanterite, langite, brochantite, gypsum, felsöbányaite) silicates (allophane and crisocolla) cuprite and native copper some of which are rather uncommon because of the very special conditions that allowed for their formation in this environment

Il sistema di monitoraggio della grotta del Farneto (BO), Marta Cristiani, Claudio Dalmonte, Jo De Waele, Monica Ghirotti

La grotta del Farneto è la più famosa cavità del Parco Naturale Regionale dei Gessi Bolognesi e Calanchi dell’Abbadessa. La grotta, scoperta nel 1871 ed esplorata nei primi del Novecento, dopo decenni di abbandono fu chiusa al pubblico agli inizi degli anni ‘90 a seguito di frane che ne avevano ostruito l’ingresso. Dopo importanti lavori di consolidamento, la grotta è stata riaperta al pubblico nell’ottobre 2008. Al fine di valutare le condizioni di stabilità delle aree aperte ai visitatori, il Dipartimento di Scienze della Terra e Geologico-Ambientali dell’Università di Bologna gestisce i dati (a frequenza oraria) provenienti da un sistema di monitoraggio costituito da 6 estensimetri e due clinometri installati in corrispondenza delle situazioni di maggiore criticità. A supporto di tali dati (aperture/chiusure di discontinuità in roccia o rotazioni di blocchi potenzialmente instabili) sono state installate tre centraline per l’acquisizione della temperatura dell’aria e dell’umidità relativa. Dall’analisi dei dati di tre anni di monitoraggio, si osserva come i movimenti risultino indipendenti dalle precipitazioni e dall’umidità relativa, mentre si riconoscono comportamenti deformativi correlabili inversamente alla temperatura dell’aria, con cicli di dilatazione/contrazione termica delle discontinuità a cui si sovrappone un effetto di isteresi per cui, nell’arco dell’anno, è rilevabile una progressiva e non recuperabile deformazione.Farneto is the most famous cave of the Regional Natural Park of “Gessi Bolognesi e Calanchi dell’Abbadessa”. The cave, discovered in 1871 and explored in the early years of the XXth century, after decennia of abandonment, was closed to the public in the early 90s because of mass movements that had obstructed the entrance. After important stabilisation works the cave was reopened to the public in October 2008. In order to evaluate the stability conditions of the areas open to visitors, the Department of Earth and Environmental Sciences of Bologna University is managing data (on an hourly basis) measured by a monitoring system composed of six extension meters and two clinometers placed in those areas having the most critical situations. Together with these instruments (that measure opening and closure of rock discontinuities or rotation of potentially unstable blocks) also three monitoring devices for temperature and relative humidity have been put in place. From the data analysis of three years of monitoring it is clear that the small movements are independent from rainfall and relative air humidity, while some of the changes are inversely correlated to temperature variations, with cycles of thermal contraction and dilatation. However, despite this cyclic behavior, the recorded deformations appear to be progressively increasing over the three years