Search results for "gypsum"
showing 10 items of 84 documents
Distribution of rare earth elements in marine sediments from the Strait of Sicily (western Mediterranean Sea): Evidence of phosphogypsum waste contam…
2010
Concentrations of rare earth elements (REE), Y, Th and Sc were recently determined in marine sediments collected using a box corer along two onshore–offshore transects located in the Strait of Sicily (Mediterranean Sea). The REE + Y were enriched in offshore fine-grained sediments where clay minerals are abundant, whereas the REE + Y contents were lower in onshore coarse-grained sediments with high carbonate fractions. Considering this distribution trend, the onshore sediments in front of the southwestern Sicilian coast represent an anomaly with high REE + Y concentrations (mean value 163.4 lg g 1) associated to high Th concentrations (mean value 7.9 lg g 1). Plot of shale-normalized REE + …
Source of calcium for pedogenic CaCO3 formation in benchmark soils of a Mediterranean semiarid environment
2004
Calcic and petrocalcic horizons (Bk and Bkm, respectively) commonly occur in soils of arid and semiarid regions. Studies carried out to investigate the source of calcium in CaCO3 formation have shown that dust and parent materials represent the main sources. The aim of this study was to investigate if gypsum may be a source of calcium for calcium carbonate formation and, eventually, to quantify it. Five soil pedons, developing on “Serie Gessoso- Solfifera”, were selected in a very representative forest Mediterranean ecosystem in Sicily (I). Pedons were opened, described in field and sampled according to the sequence of genetic horizons. Soil samples were analyzed to investigate 87/86Sr rati…
Geological development of a gypsum lake formed at the beginning of the 2oth century in central Sicily, Italy: Integration of historical data with mod…
2006
A limnological investigation was carried out on the small, endorheic lake, called Lake Sfondato, located in central Sicily (Italy). All the aquatic environments in the central part of the island are rich in salt, with conductivity values above 5 mS cm−1, and are characterized by high alkalinity values and hard waters. In addition, due to intensive agriculture, many of these ecosystems have experienced a strong anthropogenic eutrophication over the last decades. In order to better understand the functioning of these peculiar environments, the morphology, hydrology, and geochemistry, as well as several selected physical and biological characteristics of Lake Sfondato, were studied in the year…
ORIGIN AND EVOLUTION OF THE MESSINIAN BASINS DEVELOPED ON TOP OF THE SICILIAN FOLD AND THRUST BELT
2016
During the Messinian the inherited paleo-topography conditioned the depositional environments of the Mediterranean region, already strongly influenced by the effects of the salinity crisis, mainly in the central region, where seabed at that time is expected to be very uneven and shallower than Western and Eastern Mediterranean. Indeed in this area as from 15 Ma the Sicilian Fold and Thrust Belt (SFTB) was originating, characterized by a multi-stage evolution: two main shortening events generated and developed at different structural levels (shallow- and deep-seated thrusts in thin-skinned thrust-model) and at different time intervals, involving mainly the Meso-Cenozoic carbonate units of th…
Geomorphology and speleogenesis of the Vallone Ponte-Grotte d'Acqua karst system (Sant'Angelo Muxaro - Southern Sicily
2010
The "Paleorisorgenza" of the Monte Conca gypsum karst system (south-central Sicily)
2010
Surface denudation rate of gypsum in Sicily
2016
Studies on surface denudation rate of karst rocks were carried out for many years with different methods, although researches on limestones are much more numerous than those on gypsum. In Sicily the most large and complete Messinian evaporite succession of Gruppo Gessoso – Solfifero outcrops and since 1993-1994 surface denudation measurements were performed on different types of gypsum by the Micro-Erosion Meter (M.E.M.) method. MEM stations were placed on natural sites representing different lithological features of gypsum outcrops of the Island: 1) selenite gypsum with centimetre-sized crystals; 2) selenite gypsum with sub-centimetre crystals; 3) gypsum arenite; 4) microcrystalline gypsum…
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 carsismo nei gessi della Sicilia
2018
Le aree carsiche gessose della Sicilia hanno attirato l’attenzione di naturalisti e geologi sin dalla seconda metà del 1800. Tuttavia, gli studi sul carsismo nei gessi non hanno visto una costante evoluzione nel tempo; infatti, dopo un lungo periodo di indifferenza, è solo a partire dagli anni ’80 del secolo scorso, che si è assistito ad un rinnovato interesse verso questa tematica, inizialmente grazie alla realizzazione di numerose campagne di esplorazione in diverse aree carsiche gessose della Sicilia da parte di alcuni gruppi speleologici siciliani, e in un secondo momento grazie all’interesse mostrato dall’Istituto di Geologia (oggi Dipartimento di Scienze della Terra e del Mare) dell’U…