0000000000166434
AUTHOR
Claudio Ventura Bordenca
Noble gas geochemistry in seismic (Umbria, Italy) and volcanic (Grand Comore Island, Indian Ocean) regions: New methodologies and implications
The noble gases are among the most powerful geochemical tools in different geological settings. For this reason, they represent one of the most valuable tracers of geochemical processes whose variations can be straightforwardly ascribed to magmatic/crustal dynamics. In this dissertation, noble gas (He, Ne, Ar) geochemistry applied in both seismic and volcanic regions are presented. The PhD research has firstly been devoted to the test on the field of an auto-sampler for high-frequency collection of the water samples in order to be analysed for their dissolved noble gases. Then, I developed a lab-based methodology for the in-vacuum extraction of noble gases from waters collected in the coppe…
Strongly SiO2-undersaturated, CaO-rich kamafugitic Pleistocene magmatism in Central Italy (San Venanzo volcanic complex) and the role of shallow depth limestone assimilation
The Pleistocene (~460–265 ka) San Venanzo volcanic complex belongs to the IAP (Intra-Apennine Province) in central Italy, which comprises at least four small Pleistocene monogenetic volcanoes plus several unrooted pyroclastic deposits with peculiar mineralogical and whole-rock chemical compositions. San Venanzo products are strongly SiO2-undersaturated, CaO- and MgO-rich and show ultrapotassic serial character. The relatively common occurrence of calcite in the pyroclastic rocks and the overall high CaO content are interpreted in literature as primary mineral. The main rock facies at San Venanzo are calcite-rich scoria and lapilli tuffs, with minor massive lava flows, and a rare pegma…
Multi-analytical study of the medieval wall paintings from the rupestrian church Grotta del Crocifisso at Lentini (eastern Sicily): new evidence of the use of woad (Isatis tinctoria)
AbstractThis study presents the results of the examination and characterisation of the wall paintings that decorate the rupestrian church named Grotta del Crocifisso, which is located in the territory of Lentini (eastern Sicily, few tens of kilometres from Catania and Syracuse). The earliest mural paintings in the church date back to the twelfth century AD. A multi-analytical approach was adopted for the characterisation of stone materials, secondary degradation products, and pigments. For this purpose, the following techniques were used: reflected light microscopy (RLM), polarised light microscopy on thin sections (PLM), X-ray powder diffraction (XRPD), mercury intrusion porosimetry (MIP),…