Search results for "fluid geochemistry"

Hydrothermal circulation on Ischia Island (Southern Italy), revealed by an integrated geochemical, geophysical and geological approach

2011

Volcano-hosted hydrothermal systems are complex geological objects, whose thorough characterisation requires extensive and interdisciplinary work. Indeed, even thought geological, geochemical and geophysical observations offer highly significant but independent information, only an integrated multidisciplinary approach can yield a comprehensive characterisation of the chemical/physical structure of hydrothermal systems. Notwithstanding the extensive application of geological, geochemical and geophysical techniques in geothermal research, there are only a few examples in the literature of concurrent use of the three techniques [Finizola et al., 2002; Zlotnicki et al., 2009]; these studies ov…

Diffuse soil CO2 degassing from Linosa island

2014

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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…

Diffuse soil gas emissions of gaseous elemental mercury (GEM) from hydrothermal-volcanic systems: An innovative approach by using the static closed-c…

2016

This study was aimed to test a new methodological approach to carry out measurements of gaseous elemental mercury (GEM) diffusively emitted from soils in hydrothermal-volcanic environments. This method was based on the use of a static closed-chamber (SCC) in combination with a Lumex® RA-915M analyzer that provides GEM measurements in a wide range of concentrations (from 2 to 50,000 ng m-3). Gas samples were collected at fixed time intervals from the SCC positioned on the ground (time-series samples). The Lumex® inlet port was equipped with a three-way Teflon valve allowing the free entrance of air through a carbon trap, in order to: (i) prevent disturbance to the Lumex® operative flow rate …

Geochemical characterisation of gases along the dead sea rift: Evidences of mantle-co2 degassing

2016

International audience; The Dead Sea Transform (DST) fault system, where a lateral displacement between the African and Arabian plates occurs, is characterised by anomalous heat flux in the Israeli area close to the border with Syria and Jordan. The concentration of He and CO2, and isotopic composition of He and total dissolved inorganic carbon were studied in cold and thermal waters collected along the DST, in order to investigate the source of volatiles and their relationship with the tectonic framework of the DST. The waters with higher temperature (up to 57.2 °C) are characterised by higher amounts of CO2 and helium (up to 55.72 and 1.91 * 10-2 cc l-1, respectively). Helium isotopic dat…

The Monticchio crater lakes: fluid geochemistry and circulation dynamics

2011

The structure of a hydrothermal system from an integrated geochemical, geophysical and geological approach: the Ischia Island case study

2011

The complexity of volcano-hosted hydrothermal systems is such that thorough characterisation requires extensive and interdisciplinary work. We use here an integrated multidisciplinary approach, combining geological investigations with hydrogeochemical and soil degassing prospecting, and resistivity surveys, to provide a comprehensive characterisation of the shallow structure of the south-western Ischia’s hydrothermal system. We show that the investigated area is characterised by a structural setting that, although very complex, can be schematised in three sectors, namely the extra caldera sector (ECS), caldera floor sector (CFS), and resurgent caldera sector (RCS). This contrasted structura…

Dissolved CO2 in natural waters: development of an automated monitoring system and first application to Stromboli volcano (Italy)

2011

The study of geochemical parameters applied to natural systems has provided improved knowledge of geochemical mechanisms of gas/rock dissolution in natural waters that are linked to gas-water and/or water-rock interaction processes. Here we present the results of our studies focused on the development of an automated monitoring system for measuring the amount of dissolved CO2 in natural waters. The system is based on the principle of a dynamic equilibrium between water and the air as the host gas. The PCO2 measurements were carried out every four hours, and the equilibration time was around 20 minutes. Moreover, application to the thermal aquifer of Stromboli volcano during the 2009-2010 pe…