Università degli Studi di Trieste
Matematica e Geoscienze
Italia -Sono presentati e discussi alcuni dei principali risultati del progetto di ricerca nazionale (PRIN). Speleotemi di alcune grotte scelte dell'Italia settentrionale, centrale e meridionale sono stati studiati con diverse tecniche e... more
Italia -Sono presentati e discussi alcuni dei principali risultati del progetto di ricerca nazionale (PRIN). Speleotemi di alcune grotte scelte dell'Italia settentrionale, centrale e meridionale sono stati studiati con diverse tecniche e datati in spettrometria di massa con il metodo U/Th. In generale, la velocità di accrescimento dopo aver raggiunto una massima velocità durante la prima parte dell'Olocene decresce sensibilmente. Si può notare come esista un'interrelazione tra temperatura media della grotta e velocità di accrescimento. I cambiamenti del δ 13 C mostrano un trend generalmente negativo, soprattutto durante il Tardiglaciale e la prima parte dell'Olocene. Soltanto durante gli ultimi 2 ka si nota un'inversione verso valori tendenzialmente positivi. I cambiamenti nel δ 18 O degli speleotemi delle grotte Savi (TS) e Frasassi (AN) mostrano un trend prevalentemente positivo durante l'Olocene (valori compresi tra -5 e -10 ‰); al contrario il trend della stalagmite delle Grotta di Carburangeli (PA) è negativo. La luminescenza eccitata da laser degli speleotemi della grotta Savi mostra i suoi massimi nella prima parte dell'Olocene, probabilmente in relazione con lo sviluppo di suoli forestali. I valori più bassi sono quelli degli ultimi 1,5 ka. Da uno sguardo d'insieme, i dati sono in accordo con le conoscenze sui cambiamenti climatici in Italia durante il Tardiglaciale e l'Olocene. Emergono tuttavia alcuni dati problematici che suggeriscono ulteriori ricerche.
- by Leonardo Piccini and +6
- •
- Climate Change, Speleothems
Rock salt composed of halite is at least three orders of magnitude more soluble than limestone. Because of this very high solubility rock salt rarely crops out extensively at the surface and is readily dissolved leaving insoluble residue... more
Rock salt composed of halite is at least three orders of magnitude more soluble than limestone. Because of this very high solubility rock salt rarely crops out extensively at the surface and is readily dissolved leaving insoluble residue (mainly clays and marls).
Maps illustrating the different degrees of vulnerability within a given area are integral to environmental protection and management policies. The assessment of the intrinsic vulnerability of karst areas is difficult since the type and... more
Maps illustrating the different degrees of vulnerability within a given area are integral to environmental protection and management policies. The assessment of the intrinsic vulnerability of karst areas is difficult since the type and stage of karst development and the related underground discharge behavior are difficult to determine and quantify. Geographic Information Systems techniques are applied to the evaluation of the vulnerability of an aquifer in the alpine karst area of the Sette Comuni Plateau, in the Veneto Region of northern Italy. The water resources of the studied aquifer are of particular importance to the local communities. This aquifer must therefore be protected from both inappropriate use as well as possible pollution. The SINTACS and SINTACS P RO K ARST vulnerability assessment methods have been utilized here to create the vulnerability map. SINTACS P RO K ARST is an adaptation of the parametric managerial model (SINTACS) to karst hydrostructures. The vulnerability map reveals vast zones (81% of the analyzed areas) with a high degree of vulnerability. The presence of well-developed karst structures in these highly vulnerable areas facilitate water percolation, thereby enhancing the groundwater vulnerability risk. Only 1.5 of the studied aquifer have extremely high-vulnerability levels, however these areas include all of the major springs utilized for human consumption. This vulnerability map of the Sette Comuni Plateau aquifer is an indispensable tool for both the effective management of water resources and as support to environmental planning in the Sette Comuni Plateau area. r
In a mature karstic system, the realisation of galleries using the methodology of railway tunnel boring machine (TBM) involves particular problems due to the high risk of interference with groundwater (often subject to remarkable level... more
In a mature karstic system, the realisation of galleries using the methodology of railway tunnel boring machine (TBM) involves particular problems due to the high risk of interference with groundwater (often subject to remarkable level variations) and with cavities and/or thick fill deposits. In order to define groundwater features it is necessary to investigate both hydrodynamic and karstification. To define and quantify the karst phenomenon in the epikarst of the Trieste Karst (Italy), an applied geomorphological approach has been experimented with surface and cavity surveys. The surface surveys have contributed to determining the potential karst versus the different outcropping lithologies and to define the structural setting of the rocky mass also through the realisation of geostructural stations and the survey of the main lines thanks to photo-interpretation. Moreover, all the dolines and the cavities present in the area interested by the gallery have been studied by analysing the probable extension of caves and/or of the secondary fill deposits and by evaluating the different genetic models. In an area 900 m large and 27 km long, which has been studied because of the underground karst, there are 41 dolines having diameters superior to 100 m and 93 dolines whose diameters range between 100 and 50 m; the dolines whose diameters are inferior to 50 m are 282. The entrances of known and registered cavities in the cadastre records are 520.
The always increasing demand for good quality freshwater has ancient roots, and when the resource to be protect is a transboundary aquifer, the challenge is quite high, as the case of Classical Karst Reka/Timavo aquifer system, a shared... more
The always increasing demand for good quality freshwater has ancient roots, and when the resource to be protect is a transboundary aquifer, the challenge is quite high, as the case of Classical Karst Reka/Timavo aquifer system, a shared aquifer between Italy and Slovenia. The importance of this water resource depends from the use of the resource itself. About the 20% of the waters exploited by AcegasApsAmga aqueduct for drinking purposes for the Trieste Province (Italy), belongs to the Reka/Timavo aquifer system. The remaining 80% is coming from the artesian wells of the Low Isonzo Plain. The 100% of the drinkwater withdrawals of Kraski Vodovod Sezana (the Slovenian aqueduct that serve Sesana and surroundings) is coming from the Classical Karst aquifer. Already the Resolution adopted by the General Assembly of the United Nations on 11 December 2008, on the low of transboundary aquifers (A/RES/63/124), emphasize the continuing importance of the codification and progressive developmen...
- by Francesco Treu and +2
- •
Studi Trent. Sci. Nat., Acta Geol., 80 (2003): 175-184 ... © Museo Tridentino di Scienze Naturali, Trento 2005 ... Variabilità climatica nel Tardiglaciale e nell'Olocene da dati di speleotemi lungo una traversa NS in Italia ... Ugo... more
Studi Trent. Sci. Nat., Acta Geol., 80 (2003): 175-184 ... © Museo Tridentino di Scienze Naturali, Trento 2005 ... Variabilità climatica nel Tardiglaciale e nell'Olocene da dati di speleotemi lungo una traversa NS in Italia ... Ugo SAURO1*, Andrea BORSATO2, Silvia FRISIA2, ...
The constantly increasing of water demand for human consumptions has necessitated a reconstruction of the hydrogeologic characteristics and properties as well isotopic features of the aquifers of the Friuli Venezia Giulia Plain (FP). The... more
The constantly increasing of water demand for human consumptions has necessitated a reconstruction of the hydrogeologic characteristics and properties as well isotopic features of the aquifers of the Friuli Venezia Giulia Plain (FP). The DiSGAM and DICA have been engaged by the Hydraulic Survey of the FVG Region in order to coordinate an integrated study finalized to the FP confined
RIASSUNTO -Ricostruzione climatica degli ultimi 17.000 anni da una stalagmite della Grotta Savi (Trieste, Italia) -La Grotta Savi, che si apre sulle pendici del Monte Stena in Val Rosandra (Carso Triestino, Italia), consiste in una rete... more
RIASSUNTO -Ricostruzione climatica degli ultimi 17.000 anni da una stalagmite della Grotta Savi (Trieste, Italia) -La Grotta Savi, che si apre sulle pendici del Monte Stena in Val Rosandra (Carso Triestino, Italia), consiste in una rete di gallerie suborizzontali in gran parte sviluppate tra 300 e 350 metri sul livello del mare, che intersecano grandi vani per uno sviluppo di oltre 4 km. Nella parte interna della cavità è stata prelevata la stalagmite SV1, che costituisce il primo record di speleotema italiano ed europeo che copra con continuità gli ultimi 16,6 ka. La stalagmite, alta 27 cm, è stata datata grazie a 18 analisi MC-ICPMS U/Th, e sul suo profilo assiale si sono effettuate 345 analisi isotopiche con risoluzione media di 50±43 anni. La stalagmite ha iniziato a formarsi intorno a 16,6±0,7 ka, ma la crescita assiale è rimasta molto bassa, solitamente al di sotto di 10 µm/anno, fino al termine del periodo freddo del Dryas Recente, mentre nell'intervallo tra ~10,7 e ~7,6 ka si registrano i tassi di crescita più elevati, compresi tra 32 e 43 µm/anno. Il record del δ 18 O riflette la quantità d'acqua che alimentava la stalagmite, a sua volta legata alla piovosità media annua e all'evapotraspirazione in superficie. Nel suo insieme, il record del δ 18 O si correla positivamente con quello degli speleotemi della grotta di Soreq in Israele ( , ed è anticorrelato al record del δ 18 O del ghiaccio della carota GISP2 della Groenlandia (Grootes et al.1993). Viceversa, per la parte più recente della stalagmite si è verificata una correlazione positiva tra dδ 18 O calcite e temperatura media annua ricostruita per ultimi 500 anni per l'area alpina ): i picchi negativi di temperatura corrispondono a picchi negativi del δ 18 O calcite , ed il forte trend positivo nelle temperature dal 1800 AD ad oggi è replicato nel trend del δ 18 O.
Razumevanje kra{kih pojavov in razvoj hidrogeolo{kega modela, ki bi bil uporaben povsod na razvitem krasu, bi bilo splo{no koristno. Kras, ki je aee razmeroma dobro raziskan in poznan, je lahko idelano podro~je za multidisciplinarne... more
Razumevanje kra{kih pojavov in razvoj hidrogeolo{kega modela, ki bi bil uporaben povsod na razvitem krasu, bi bilo splo{no koristno. Kras, ki je aee razmeroma dobro raziskan in poznan, je lahko idelano podro~je za multidisciplinarne raziskave. Njegova geologija, hidrologija in zgodovina sta predmet raziskav aee od 16. stoletja dalje. Dandanes kontinuirni monitoring podzemeljskih voda, digitalni model reliefa, odkritje in raziskava nekaterih novih jam je omogo~ilo izdelavo karte ranljivosti. Na podlagi izsledkov teh odkritij predlagajo avtorji sodelovanje evropskih raziskovalcev pri razvoju hidrodinami~nega modela najbolj znanega kra{kega predela na svetu, to je klasi~nega Krasa.
- by Luca Zini and +2
- •
An active Deep-seated Gravitational Slope Deformation (DGSD) has been recently identified in the Carnic Alps above the Cercevesa torrent in the northern part of the Friuli Venezia Giulia Region (Italy). The phenomenon interests an area of... more
An active Deep-seated Gravitational Slope Deformation (DGSD) has been recently identified in the Carnic Alps above the Cercevesa torrent in the northern part of the Friuli Venezia Giulia Region (Italy). The phenomenon interests an area of about 1 km2 and involves Devonian verticalized limestones and mudstones over standing Hockwipfel Formation. The most evident morphological feature of the Cercevesa DGSD is
Although the Cordillera de la Sal, close to San Pedro de Atacama (Chile), is one of the driest places on Earth, it contains extensive cave systems that have developed in halite. A detailed morphological study of these caves, combined with... more
Although the Cordillera de la Sal, close to San Pedro de Atacama (Chile), is one of the driest places on
Earth, it contains extensive cave systems that have developed in halite. A detailed morphological study of
these caves, combined with 16 AMS radiocarbon ages on wood and bone fragments recovered from cave
ceilings and diamictons, have allowed us to define when these systems formed and when sediments were
emplaced. The sometimes huge cave passages appear to have formed in less than 2000 years by a succession
of short-lived flash floods, probably after single extreme rain events.
Earth, it contains extensive cave systems that have developed in halite. A detailed morphological study of
these caves, combined with 16 AMS radiocarbon ages on wood and bone fragments recovered from cave
ceilings and diamictons, have allowed us to define when these systems formed and when sediments were
emplaced. The sometimes huge cave passages appear to have formed in less than 2000 years by a succession
of short-lived flash floods, probably after single extreme rain events.
- by Paolo Forti and +4
- •
- Chile, Speleology, Speleogenesis, Evaporites
Interesting salt caves were recently discovered in one of the driest places on earth, the Atacama desert (Chile). The caves, sometimes over 1 km long, host important and widespread active halite speleothems among which are peculiar... more
Interesting salt caves were recently discovered in one of the driest places on earth, the Atacama
desert (Chile). The caves, sometimes over 1 km long, host important and widespread active halite
speleothems among which are peculiar macrocrystalline stalactites, described here for the first time. The
macrocrystalline stalactites consist of a sequence of interpenetrated halite cubes, often with a hopper
structure. The halite cubes are always oriented with the long diagonals coincident with the speleothem
elongation axis. A few of these stalactites exhibit a perfectly vertical structure, while most of these
speleothems are inclined (with a deviation from the verticality up to 40-50 degrees). Internal feeding
tubes are completely absent. The evolution of these speleothems is induced only by condensation/
evaporation processes. While the feeding of these speleothems is always related to condensation
processes, their evolution is controlled by several interconnected factors: 1 - air current distribution close
to the speleothems, 2 - condensation and evaporation processes, and 3 - capillary, and/or gravitational
movements of the solution along the speleothems. In many cases these factors allow for the development
of strange hopper structures, giving rise to wide rectangular thin flat tabular crystals. Finally in a single
location, peculiar bidimensional pyramidal structures of halite crystals have developed where the
gravitational flow of the feeding solutions meets a strong upward air flow.
desert (Chile). The caves, sometimes over 1 km long, host important and widespread active halite
speleothems among which are peculiar macrocrystalline stalactites, described here for the first time. The
macrocrystalline stalactites consist of a sequence of interpenetrated halite cubes, often with a hopper
structure. The halite cubes are always oriented with the long diagonals coincident with the speleothem
elongation axis. A few of these stalactites exhibit a perfectly vertical structure, while most of these
speleothems are inclined (with a deviation from the verticality up to 40-50 degrees). Internal feeding
tubes are completely absent. The evolution of these speleothems is induced only by condensation/
evaporation processes. While the feeding of these speleothems is always related to condensation
processes, their evolution is controlled by several interconnected factors: 1 - air current distribution close
to the speleothems, 2 - condensation and evaporation processes, and 3 - capillary, and/or gravitational
movements of the solution along the speleothems. In many cases these factors allow for the development
of strange hopper structures, giving rise to wide rectangular thin flat tabular crystals. Finally in a single
location, peculiar bidimensional pyramidal structures of halite crystals have developed where the
gravitational flow of the feeding solutions meets a strong upward air flow.
- by Jo De Waele and +2
- •
- Mineralogy, Speleothems, Speleogenesis, Evaporite Karst
To set an approach for the future territorial planning, the Geological Survey of Friuli Venezia Giulia Region, through the researchers of Trieste University, started a program of debris-flow risk analysis using Flo-2D software as tool to... more
To set an approach for the future territorial planning, the Geological Survey of Friuli Venezia Giulia Region, through the researchers of Trieste University, started a program of debris-flow risk analysis using Flo-2D software as tool to delimit the hazardous areas. In the present paper, as a case study, a debris flow, called Fella sx, occurring in a torrent catchment was analyzed. The choice was due to the abundance of information about past events, inundated areas, rain fall, geology and to its representativeness. An initial back-analysis investigation identified a couple of representative rheological parameters. Riverbed samples were collected, sieve analyses were performed and rheological tests were carried out on the fraction finer than 0.063 mm using a rotationally controlled stress rehometer equipped with the serrated parallel plate geometry. The shear dependent behaviour was examined at different concentrations ranging from 33 to 48%, by weight. Viscosity data treatment was performed to determine the most suitable rheological model to provide the best approximation of the debris-flow behaviour. The rheological parameters, derived from experimental data, were used and compared with those obtained through the back-analysis and with the real inundated area. Data obtained through rheological analysis are useful in constructing scenarios of future events where no data for back-analysis are available.