scholarly journals Application of Geostatistical Tools to the Geochemical Characterization of the Peloritani Mts (Sicily, Italy) Aquifers

Water ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3269
Author(s):  
Marianna Cangemi ◽  
Valentina Censi ◽  
Paolo Madonia ◽  
Rocco Favara

Sources of groundwater contaminants in inhabited areas, located in complex geo-tectonic contexts, are often deeply interlocked, thus, making the discrimination between anthropic and natural origins difficult. In this study, we investigate the Peloritani Mountain aquifers (Sicily, Italy), using the combination of probability plots with concentration contour maps to retrieve an overall view of the groundwater geo-chemistry with a special focus on the flux of heavy metals. In particular, we present a methodology for integrating spatial data with very different levels of precision, acquired before and during the “geomatic era”. Our results depict a complex geochemical layout driven by a geo-puzzle of rocks with very different lithological natures, hydraulically connected by a dense tectonic network that is also responsible for the mixing of deep hydrothermal fluids with the meteoric recharge. Moreover, a double source, geogenic or anthropogenic, was individuated for many chemicals delivered to groundwater bodies. The concentration contour maps, based on the different data groups identified by the probability plots, fit the coherency and congruency criteria with the distribution of both rock matrices and anthropogenic sources for chemicals, indicating the success of our geostatistical approach.

2002 ◽  
Vol 125 (1) ◽  
pp. 358-364 ◽  
Author(s):  
D. Caceres ◽  
J. R. Reisel ◽  
A. Sklyarov ◽  
A. Poehlman

In this study, a laboratory test procedure to mimic the life cycle of the small air-cooled engines in field operation is developed. A characterization of exhaust emissions over the life cycle of the engines is achieved with special focus given to the hydrocarbon emissions. Both Briggs and Stratton four-stroke (four-cycle) overhead-valve and side-valve engines with a nominal power output of 3.7 kW (5 hp) are used in this study. Different levels of emissions are observed for each type of engine configuration, and it is noted that the hydrocarbon emissions changed more than CO or NOx emissions. These data support the idea that combustion chamber deposits (CCD) are a significant cause of deteriorating emissions. Chemical analysis techniques are applied to the CCD, and it is found that the deposits consist primarily of polynuclear aromatic compounds and unsaturated hydrocarbons.


2016 ◽  
Author(s):  
Antonio Lanzirotti ◽  
◽  
Stephen R. Sutton ◽  
Matt Newville ◽  
Jeffrey P. Fitts ◽  
...  

2020 ◽  
Author(s):  
Nathalia Pineda rodriguez ◽  
◽  
Vanessa Colás ◽  
Vanessa Colás ◽  
José María González-Jiménez ◽  
...  

2021 ◽  
pp. 1-20
Author(s):  
I.M. Bhat ◽  
T. Ahmad ◽  
D.V. Subba Rao ◽  
N.V. Chalapathi Rao

Abstract The Ladakh Himalayan ophiolites preserve remnants of the eastern part of the Neo-Tethyan Ocean, in the form of Dras, Suru Valley, Shergol, Spongtang and Nidar ophiolitic sequences. In Kohistan region of Pakistan, Muslim Bagh, Zhob and Bela ophiolites are considered to be equivalents of Ladakh ophiolites. In western Ladakh, the Suru–Thasgam ophiolitic slice is highly dismembered and consists of peridotites, pyroxenites and gabbros, emplaced as imbricate blocks thrust over the Mesozoic Dras arc complex along the Indus Suture Zone. The Thasgam peridotites are partially serpentinized with relict olivine, orthopyroxene and minor clinopyroxene, as well as serpentine and iron oxide as secondary mineral assemblage. The pyroxenites are dominated by clinopyroxene followed by orthopyroxene with subordinate olivine and spinel. Gabbros are composed of plagioclase and pyroxene (mostly replaced by amphiboles), describing an ophitic to sub-ophitic textural relationship. Geochemically, the studied rock types show sub-alkaline tholeiitic characteristics. The peridotites display nearly flat chondrite-normalized rare earth element (REE) patterns ((La/Yb)N = 0.6–1.5), while fractionated patterns were observed for pyroxenites and gabbros. Multi-element spidergrams for peridotites, pyroxenites and gabbros display subduction-related geochemical characteristics such as enriched large-ion lithophile element (LILE) and depleted high-field-strength element (HFSE) concentrations. In peridotites and pyroxenites, highly magnesian olivine (Fo88.5-89.3 and Fo87.8-89.9, respectively) and clinopyroxene (Mg no. of 93–98 and 90–97, respectively) indicate supra-subduction zone (SSZ) tectonic affinity. Our study suggests that the peridotites epitomize the refractory nature of their protoliths and were later evolved in a subduction environment. Pyroxenites and gabbros appear to be related to the base of the modern intra-oceanic island-arc tholeiitic sequence.


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