Search results for "LCA"

The genesis of actively growing siliceous stromatolites: Evidence from Lake Specchio di Venere, Pantelleria Island, Italy

2010

This study documents the attributes of siliceous stromatolites growing in the Lake Specchio di Venere, on the volcanic island of Pantelleria, Italy, in a setting characterized by very shallow cold waters and pools and by scattered hydrothermal activity, which exhales mainly CO2, at emission point temperatures of 34 to 58 °C. The saturation indexes indicate that the lake waters are saturated with respect to tridymite, cristobalite, chalcedony and quartz, and slightly undersaturated with respect to amorphous silica. Common roughly laminated and poorly lithified stromatolites show scanning electron microscope (SEM) evidence for silicified microbial mat structures, including biofilms, filamento…

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 ARGONAUTICA ORPHICA VERSION FOR THE VOYAGE OF THE ARGONAUTS: A GEO-ANALYSIS

2017

This study traces and analyzes the itinerary followed by Argo and her crew, according to the unknown author of Argonautica Orphica: The voyage of the Argonauts from Iolcos to Colchis and their return following a different path, from Phasis River through central Europe to the Atlantic Ocean and then through the Mediterranean Sea. Conclusions are drawn about whether such a voyage could be possible in the remote antiquity and the “problematic” points of the description are pointed out.

Volcanism at Slab Tear Faults: the Diamante-Enotrio-Ovidio volcanic complex (offshore north-west Calabria)

2018

Several arc-shape sectors form the central and southern part of the Italian peninsula, representing the emerged portion of the continental crust disjoined by slab tear faults (e.g., Olevano-Antrodoco, Ortona-Roccamonfina Tindari-Letojanni faults). These sectors are characterized by different drift velocities and tectonic patterns, while above to them important volcanic phases developed, such as the Vulture volcano (onshore) and the Vulcano-Lipari-Salina alignment (offshore). In the Tyrrhenian basin such kind of volcanism is still poorly investigated and understood though it could be revealed by low-resolution geophysical anomalies and volcanic seafloor morphologies. This is probably due to …

Los créditos perdidos

1999

Local interest groups and the perception of power in Spanish cities

2018

Studies on local interest groups have generated a considerable number of theories on urban power that have eventually become the basis of far-reaching approaches on democracy and collective action. Such literature has been especially concerned with discovering who governs the city, paving the way for discussions on elitism, pluralism and urban regimes. Some approaches consider that the business elite dominates local politics, while other theories assert that interests other than business (neighbors, environmentalists, faith-based organizations, civic groups) have been gaining relevance and access to local government. The POLLEADER survey (2006) provided data on the influence of certain soci…

Soft-sediment deformation structures (SSDS) in Pleistocene calcarenites of Favignana island (Sicily, Italy)

2013

Selenium mobilization during Rain-Soil Interaction at Etna volcano

2010

Humans are attracted by the fertile properties of volcanic soils. Currently around 10% of the world population lives within active volcanic areas. Volcanoes emit enormous amounts of potentially toxic elements, even in the absence of obvious volcanic activity. Selenium is particularly interesting due to it geochemical similarities with sulphur, a major compound in volcanic gasses. Although selenium (Se) is an essential element for humans, ingestion of an excess amount of Se can produce adverse effects. Mt. Etna, the biggest volcano in Europe, is persistently active for the last 200,000 years. It is one of the most intensely monitored volcanoes. In the area, volcanic gasses, rainwater and gro…

Continental degassing of helium in an active tectonic setting (northern Italy): the role of seismicity

2020

AbstractIn order to investigate the variability of helium degassing in continental regions, its release from rocks and emission into the atmosphere, here we studied the degassing of volatiles in a seismically active region of northern Italy (MwMAX = 6) at the Nirano-Regnano mud volcanic system. The emitted gases in the study area are CH4–dominated and it is the carrier for helium (He) transfer through the crust. Carbon and He isotopes unequivocally indicate that crustal-derived fluids dominate these systems. An high-resolution 3-dimensional reconstruction of the gas reservoirs feeding the observed gas emissions at the surface permits to estimate the amount of He stored in the natural reserv…

Polymer-Functionalised Nanograins of Mg-Doped Amorphous Calcium Carbonate via a Flow-Chemistry Approach

2019

Calcareous biominerals typically feature a hybrid nanogranular structure consisting of calcium carbonate nanograins coated with organic matrices. This nanogranular organisation has a beneficial effect on the functionality of these bioceramics. In this feasibility study, we successfully employed a flow-chemistry approach to precipitate Mg-doped amorphous calcium carbonate particles functionalized by negatively charged polyelectrolytes&mdash