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Lo Mastro, S.
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Lo Mastro, S.
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- PublicationRestrictedHydrothermal Breccia Textures and Processes: Lisca Bianca Islet, Panarea Volcano, Aeolian Islands, Italy(2011)
; ; ; ; ; ;Cas, R. ;Giordano, G. ;Balsamo, F. ;Esposito, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Lo Mastro, S. ; ; ;; Panarea is a largely submarine to partly subaerial Quaternary lava dome complex-stratovolcano with a long-lived, active, shallow hydrothermal system, located in the Aeolian Islands volcanic arc of southern Italy. The emergent top of the volcano forms a small archipelago, made up of calc-alkaline basaltic andesite to rhyolite lava domes (ca. 150–20 ka). We document the facies outcropping on Lisca Bianca islet, Panarea archipelago, based on grain size, clast fabric, and degree of hydrothermal alteration, identifying coherent facies, boulder breccia facies, cobble breccia facies, pebble breccia facies, and pervasively altered andesite facies (alunite-marcasite-sulfur). The breccias all have ubiquitous jigsaw-fit clast textures, and are variably hydrothermally altered. The breccias are interpreted as hydrothermal breccias and are distinguished from primary volcanic facies based on their distinguishing characteristics. The breccias formed through a cyclical process, involving the following: stage 1: progressive build-up of fluid pressure toward the level of the tensile strength of the host andesite; stage 2: incipient fracturing of the andesite when fluid pressure approaches and then exceeds the tensile strength of the andesite under critical fracturing conditions; stage 3: pervasive fracturing of the host andesite, leading to an increase in permeability as a network of fractures develops; stage 4: declining pressure, with fluid flow rates that lead to infilling and sealing of fractures by natroalunite, thereby reducing permeability, leading to progressive build-up of fluid pressure again, and the beginning of a new cycle.461 25 - PublicationRestrictedOrbitally forced paleoenvironmental and paleoclimate changes in the late postevaporitic Messinian of the central Mediterranean Basin(2012)
; ; ; ; ; ; ; ; ;Cosentino, D.; Dipartimento di Scienze Geologiche, Università degli Studi Roma Tre, Largo San Leonardo Murialdo, 1-00146 Rome, Italy ;Bertini, A.; Dipartimento di Scienze della Terra, Università degli Studi di Firenze, Via G. La Pira, 4-50121 Firenze, Italy ;Cipollari, P.; Dipartimento di Scienze Geologiche, Università degli Studi Roma Tre, Largo San Leonardo Murialdo, 1-00146 Rome, Italy ;Florindo, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Gliozzi, E.; Dipartimento di Scienze Geologiche, Università degli Studi Roma Tre, Largo San Leonardo Murialdo, 1-00146 Rome, Italy ;Grossi, F.; Dipartimento di Scienze Geologiche, Università degli Studi Roma Tre, Largo San Leonardo Murialdo, 1-00146 Rome, Italy ;Lo Mastro, S.; Dipartimento di Scienze Geologiche, Università degli Studi Roma Tre, Largo San Leonardo Murialdo, 1-00146 Rome, Italy ;Sprovieri, M.; Istituto per l’Ambiente Marino Costiero, Consiglio Nazionale delle Ricerche, Via del Mare 3, 91021 Torretta Granitola, Mazara (TP), Italy; ; ; ; ; ; ;Paleoenvironmental and paleoclimate changes that occurred during the late postevaporitic stage of the Mediterranean Basin in the Messinian foreland domain of the Adriatic region offer a new perspective on the relationship between orbital forcing and climate response. The magnetic susceptibility record of the Fonte dei Pulcini A section (Maiella Mountains, Italy) allows us to orbitally tune the record between 5.394 and 5.336 Ma and to temporally constrain the paleoenvironmental and paleoclimate changes evidenced by quantitative paleontological (palynomorphs, ostracods, and calcareous nannofossils), stable isotope (δ18O and δ13C), and X-ray diffraction (XRD) analyses. The base of the Fonte dei Pulcini A section is characterized by Paratethyan ostracods and dinocysts, which point to the late Messinian Lago-Mare biofacies (Loxocorniculina djafarovi zone) of the Mediterranean Messinian stratigraphy. From paleontological and geochemical (δ18O) analyses, there is no evidence of a marine incursion in the Fonte dei Pulcini A section. The major changes in terms of paleodepth, paleosalinity, evaporation versus precipitation, aridity versus humidity, and reworking processes occurred in the upper part of the Fonte dei Pulcini A section, during the last Messinian insolation cycle (i-cycle 511/512), which is characterized by high-amplitude oscillations. In contrast, the lower part of the Fonte dei Pulcini A section, which was deposited during relatively low-amplitude insolation cycles, is characterized by more stable environmental conditions. Comparing summer insolation with the paleoenvironmental changes at the Fonte dei Pulcini A section, we identify delays of several thousands of years between orbital forcing and climate response.2235 31