Search results for "Ilici"
showing 10 items of 238 documents
Water resource assessment in karst and fractured aquifers of Termini Imerese-Trabia Mts. (Northern central Sicily, Italy).
2014
The carbonatic siliciclastic Mesozoic reliefs of Termini Imerese-Trabia Mts. (Northern central Sicily) were selected in order to investigate groundwater resources, as these fissured to karstic aquifers are used for potable water supply. These reliefs, part of the Sicilian Apennine Chain, consist of a tectonic units (deformed and emplaced during the Miocene-Pleistocene, and collapsed during the Plio-Pleistocene) mostly formed by clayey pelagic limestones (Sicilidi domain) overthrusting Meso-Cenozoic carbonate and silicoclastic rocks (Imerese Basin, Late Triassic-Early Oligocene) and terrigenous covers (Numidian Flysch, Late Oligocene-Early Miocene). The evolution of karstic network and subsu…
Zircon ages defining deposition of the Palaeoproterozoic Soutpansberg Group and further evidence for Eoarchaean crust in South Africa
2014
Abstract The precise age of the volcano-sedimentary Soutpansberg Group, which was deposited upon the Palala shear belt separating the Kaapvaal Craton from the Central Zone of the Limpopo Belt, has long been debated. The Soutpansberg Group is subdivided into a lower and upper succession, which are separated from each other by a prominent regional unconformity. Zircon grains from silicic pyroclastic rocks of both successions were investigated in order to constrain the timing of deposition of the Soutpansberg Group rocks. The zircon grains of the investigated samples from both successions yield a wide range of ages, spanning from 1831 to 3937 Ma. Most of the zircon grains have rounded shapes, …
The viscous-brittle transition of crystal-bearing slilic melt: direct observation of magma rupture and healing
2012
Magmas may fl ow or break depending on their deformation rate. The transition between such viscous and brittle behavior controls the style of volcanic eruptions. While the brittle failure of silicate melts is reasonably well characterized, the effect of crystals on the viscous-brittle transition has not yet been constrained. Here we examine the effect of suspended crystals on the mechanical failure of magmas using torsion experiments performed at temperatures (600‐ 900 °C), strain rates (10 ‐4 ‐10 ‐1 s ‐1 ), and confi ning pressures (200‐300 MPa) relevant for volcanic systems. We present a relationship that predicts the critical stress and associated strain rate at which magmas fail as a fu…
Late Archaean foreland basin deposits, Belingwe greenstone belt, Zimbabwe
2001
Abstract The c. 2.65 Ga old sedimentary Cheshire Formation of the Belingwe greenstone belt (BDB), central Zimbabwe, has been studied in detail for the first time to shed some light on the much debated evolution of this classical belt. The Cheshire Formation rests sharply on a mafic volcanic unit (Zeederbergs Formation) and comprises a basal, eastward-sloping carbonate ramp sequence built of shallowing-upward, metre-scale sedimentary cycles. The cycles strongly resemble Proterozoic and Phanerozoic carbonate cycles and might have formed by small-scale eustatic sea level changes. The top of the carbonate ramp is represented by a karst surface. The carbonates are overlain by and grade laterally…
Freshwater discharge and sediment dispersal — Control on growth, ecological structure and geometry of Late Miocene shallow-water coral ecosystems (ea…
2007
Abstract Insolation-driven oceanographic changes are well documented in the Mediterranean deep-sea record and reflect episodes of high precipitation and/or freshwater discharge. In the shallow-water record, however, changes in relative sea-level and sea surface temperature are usually regarded as prime controls on Miocene coral reefs, whereas pulses of freshwater influx represent a hitherto unrecognized factor influencing their growth, ecological structure and geometry. On the island of Crete (NW Messara Basin, Greece) early Tortonian coral biostromes occur associated with deltas along the basin margin and rimming islands formed by large uplifted tectonic blocks. In turbid delta environment…
Lowstand carbonates, highstand sandstones?
2003
The sedimentary facies, sediment dynamics and sequence architecture of modern high-energy shelves in the mid and high latitudes are largely governed by wave abrasion processes. Cool-water carbonates may form there, if the influx and/or net accretion of siliciclastics is kept at a minimum. Little dilution of the carbonate produced in situ is generally promoted by a wide "epicontinental" shelf, subdued topography of the adjacent mainland, the predominance of limestone outcrops, and an arid climate. The aforementioned requirements are rarely met, and thus will automatically lead to the formation of mixed siliciclastic-cool-water carbonates. Such an example is found in the Early to Mid-Miocene …
Silicon Strip Detectors for the ATLAS End-Cap Tracker at the HL-LHC
2017
El LHC se ha convertido en el acelerador más potente de todos los tiempos. Su principal objetivo es dar respuesta a las limitaciones del Modelo Estándar y revelar la física más allá de él. El descubrimiento del bosón de Higgs en 2012 supuso el comienzo de una era en el campo de la física de partículas donde conseguir la mayor precisión posible en las medidas es vital. En el LHC se aceleran y colisionan protones con una energía nominal de centro de masas de 14 TeV y una luminosidad instantánea nominal de 10^34 cm−2 s−1. Para la máxima luminosidad, los protones son acelerados en paquetes de 1.15 ×10^11 protones cada uno, con una frecuencia de 40 MHz (esto supone una colisión cada 25 ns). Esta…
An Off-On-Off Fluorescent Sensor for pH Windows Based on the 13aneN4-Zn 2+ System
2016
International audience; The new ligand L was prepared and features a 13-membered tetraaza macrocyclic ring with a 1,8-naphthalimide fluorophore appended to a C atom of its backbone. The protonation constants of L as well as its complexation constants with Zn2+ ions were determined in 1:1 water/methanol solutions by potentiometric titrations. Fluorimetric pH titrations were performed with L alone and L in the presence of Zn2+ ions (1:1), and the species distributions (%) versus pH were compared. A window-shaped fluorescence trend was observed with pH for the L/Zn2+ system, which behaves as an off-on-off pH sensor. The on window is centred in the 6.5-7.5 pH range, in correspondence with the f…
Metrología por fibra óptica para la detección de pequeños desplazamientos
2010
En este trabajo se presenta una metodología para la medida de deflexiones en el rango de las micras en membranas termoneumáticas de silicio. El método se basa en la interferometría por fibra óptica con el cual se estudió el comportamiento estático de una membrana de silicio de 10 mm de grosor, 5 mm de lado y 300 mm de bulk, la cual se pegó sobre un porta muestras de vidrio. Por medida estática se entiende la medida de la deflexión de las membranas considerando únicamente la respuesta de éstas a la fuente de radiación infrarroja que las estimula.
La relazione tra il kata podas e le traduzioni di Taleleo dei rescritti in latino del Codex
2013
Il contributo mira a dimostrare, attraverso il confronto tra le traduzioni letterali di Taleleo e quelle dell'anonimo autore del kata podas, che la scelta dell'antecessore di cambiare metodo di insegnamento e non dettare più proprie traduzioni letterali dopo il terzo libro del Codice, non dipese da ragioni di metodo di insegnamento (come sostenuto in dottrina) ma da esigenze pratiche, legate al poco tempo avuto a disposizione per la redazione del commentario al secondo Codice di Giustiniano.