Search results for "Geochemistry"

Geochemical fingerprints of brannerite (UTi 2 O 6 ): an integrated study

2020

AbstractBrannerite (UTi2O6) is among the major uranium-bearing minerals found in ore deposits, however as it has been long considered as a refractory mineral for leaching it is currently disregarded in ore deposits. Brannerite is found in a variety of geological environments with the most common occurrences being hydrothermal and pegmatitic. On the basis of scanning electron microscopy observations coupled with electron probe micro-analyses and laser ablation inductively-coupled plasma mass spectrometer analyses, this study describes the morphological features and the major- and trace-element abundances of brannerite samples from five hydrothermal and five pegmatitic localities across the w…

In situ micro-Raman and X-ray diffraction study of diamonds and petrology of the new ureilite UAE 001 from the United Arab Emirates

2008

International audience; A new olivine-pigeonite ureilite containing abundant diamonds and graphite was found in the United Arab Emirates. This is the first report of a meteorite in this country. The sample is heavily altered, of medium shock level, and has a total weight of 155 g. Bulk rock, olivine (Fo79.8-81.8) and pyroxene (En73.9-75.2, Fs15.5-16.9, Wo8.8-9.5) compositions are typical of ureilites. Olivine rims are reduced with Fo increasing up to Fo96.1-96.8. Metal in these rims is completely altered to Fehydroxide during terrestrial weathering. We studied diamond and graphite using micro-Raman and in situ synchrotron X-ray diffraction. The main diamond Raman band (LO=TO mode at ~1332 c…

Aquatic Macrophytes Occurrence in Mediterranean Farm Ponds: Preliminary Investigations in North-Western Sicily (Italy)

2021

Mediterranean wetlands are severely affected by habitat degradation and related loss of biodiversity. In this scenario, the wide number of artificial farm ponds can play a significant role in the biodiversity conservation of aquatic flora. In the present contribution we show the preliminary results of a study on Mediterranean farm ponds of north-western Sicily (Italy), aimed to investigating the environmental factors linked to the occurrence of submerged macrophytes (vascular plants and charophytes). We studied the aquatic flora of 30 ponds and determined the chemical and isotopic composition of their water bodies on a subset of the most representative 10 sites. Results show that (1) farm p…

Isotope geochemistry of bulk carbonate from the CRP-3 drillhole, Victoria Land Basin, Antarctica.

2003

Geogenic carbon dioxide degassing from active tectonic areas of the Balkan Peninsula

2023

Sin dagli anni ’70, la ricerca scientifica ha evidenziato una forte relazione tra il degassamento di carbonio profondo e le aree tettonicamente attive, sottolineando l’elevata importanza del contributo di queste emissioni nella quantificazione del carbonio globale. La Penisola Balcanica presenta grandi aree caratterizzate da degassamento di carbonio di origine mantellica, da attività vulcaniche Quaternarie, da un’elevata sismicità e da strutture tettoniche a scala regionale. Purtroppo, la stima del degassamento di anidride carbonica profonda in quest’area è ancora poco studiata. La ricerca di questa tesi di dottorato si è focalizzata sulla (i) stima dell’output di carbonio profondo dalle gr…

Recognition of earthquake-induced damage in the Abakainon necropolis (NE Sicily): results from geo-morphological, geophysical and numerical analyses

2017

Seismotectonic activity and slope instability are a permanent threat in the archaeological site of Abakainon and in the nearby village of Tripi in NE Sicily. In recent times, signs of an ancient earthquake have been identified in the necropolis of Abakainon which dating was ascertained to the first century AD earthquake. The site is located on a slope of Peloritani Mts. along the Tindari Fault Line and contains evidence for earthquake-induced landslide, including fallen columns and blocks, horizontal shift and counter slope tilting of the tomb basements. In this paper, we used an integrated geomorphological and geophysical analysis to constrain the landslide. The research was directed to th…

BIFOCAL PAIRS OF IMAGES FOR LOW-COST SURVEY IN CLOSE RANGE PHOTOGRAMMETRY

2019

Abstract. This paper present a method for close range photogrammetry based on an camera positioning scheme in which two cameras capture an equal portion of an object at the same scale, but have different focal lengths and camera-to-object distances. This scheme is alternative to the stereoscopic scheme and is associated with a system of equations which permits one to calculate first the relief displacement of points on a photograph and then their relief relative to a reference plane. The obtained relief and relief displacement values can be used to produce low-cost orthophotographs by using software for image processing, which doesn’t need to be dedicated, but has to provide measurement and…

The magnesium isotope record of cave carbonate archives

2012

Here we explore the potential of magnesium (δ<sup>26</sup>Mg) isotope time-series data as continental climate proxies in speleothem calcite archives. For this purpose, a total of six Pleistocene and Holocene stalagmites from caves in Germany, Morocco and Peru and two flowstones from a cave in Austria were investigated. These caves represent the semi-arid to arid (Morocco), the warm-temperate (Germany), the equatorial-humid (Peru) and the cold-humid (Austria) climate zones. Changes in the calcite magnesium isotope signature with time are compared against carbon and oxygen isotope records from these speleothems. Similar to other proxies, the non-trivial interaction of a …

Temperature variability in the Iberian Range since 1602 inferred from tree-ring records

2017

Abstract. Tree rings are an important proxy to understand the natural drivers of climate variability in the Mediterranean Basin and hence to improve future climate scenarios in a vulnerable region. Here, we compile 316 tree-ring width series from 11 conifer sites in the western Iberian Range. We apply a new standardization method based on the trunk basal area instead of the tree cambial age to develop a regional chronology which preserves high- to low-frequency variability. A new reconstruction for the 1602–2012 period correlates at −0.78 with observational September temperatures with a cumulative mean of the 21 previous months over the 1945–2012 calibration period. The new IR2Tmax reconstr…

Hot water injection in relation to 1982-84 microseismic events at Campi Flegrei Caldera by thermo-hydro-mechanical simulation

2020

The repeated deformations and seismic unrests at Campi Flegrei caldera (southern Italy) have been identified due to a fluid injection source in volcano active area. We investigated the role of hot water injection in the seismic unrests of 1982-1984 with a view to gaining insights into the caldera’s dynamics, by applying coupled TOUGHREACT-FLAC3D simulator to our computational domain of 10 × 1 × 3 km with a single-phase steam isothermal (HM) and non-isothermal (THM) simulations comparison. The results indicated that the overlying caprock blocks the uprising hot water injection, leading to the building up of pore pressure and shear stress underneath over time. This process substantially modif…