Pliocene crustal shortening on the Tyrrhenian side of the northern Apennines: evidence from the Gavorrano antiform (southern Tuscany, Italy)

The northern Tyrrhenian Sea and the inner northern Apennines are classically regarded as a late Miocene–Pleistocene back-arc system developed as a consequence of slab rollback along active subduction zones. We present new geological and structural data on the Gavorrano antiform, a key sector of the inner northern Apennines. Lying close to the northern Tyrrhenian Sea, it provides clear evidence of Pliocene shortening deformation and magma emplacement. The orientation of 1 (N50°E–N80°E) derived by fault slip data inversion is consistent with a general ENE–WSW shortening direction. Furthermore, this ENE–WSW-trending orientation of 1 is compatible with the compressive deformation recorded in coeval sedimentary basins. On this basis we suggest that the inner northern Apennines were affected by crustal shortening during the Pliocene. This scenario matches well geophysical data suggesting that since the Late Messinian (6–5 Ma) subduction rollback and back-arc extension strongly decreased in the northern Tyrrhenian Sea, whereas they continued as active processes in the southern Tyrrhenian Sea

SITOGEO: A geographic database used for GIS applications

This contribution aims to present the geographic database “SITOGEO” developed with GIS technology. This database manages data of different nature, source and resolution (land images, digital elevation model, cartographic maps and vector data) covering the whole of Italy. In this paper we show that our database can be used for the assessment, management and mitigation of risks regarding the preservation of cultural heritage and as valid support for the remote-sensing technologies

Fissural volcanism, polygenetic volcanic fields, and crustalthickness in the Payen Volcanic Complex on the central Andes foreland (Mendoza, Argentina)

Shield volcanoes, caldera-bearing stratovolcanoes, and monogenetic cones compose the large fissural Payen Volcanic Complex, located in the Andes foreland between latitude 35\uc2\ub0S and 38\uc2\ub0S. The late Pliocene-Pleistocene and recent volcanic activity along E-W trending eruptive fissures produced basaltic lavas showing a within-plate geochemical signature. The spatial distribution of fractures and monogenetic vents is characterized by self-similar clustering with well defined power law distributions. Vents have average spacing of 1.27 km and fractal exponent D = 1.33 defined in the range 0.7-49.3 km. The fractal exponent of fractures is 1.62 in the range 1.5-48.1 km. The upper cutoffs of fractures and vent fractal distributions (about 48-49 km) scale to the crustal thickness in the area, as derived from geophysical data. This analysis determines fractured media (crust) thickness associated with basaltic retroarc eruptions. We propose that the Payen Volcanic Complex was and is still active under an E-W crustal shortening regime. \uc2\ua9 2008 by the American Geophysical Union

Pliocene crustal shorthening on the Tyrrhenian side of the northern Apennones: evidence from the Gavorrano antiform (southern Tuscany, Italy)

The northern Tyrrhenian Sea and the inner northern Apennines are classically regarded as a late Miocene-Pleistocene back-arc system developed as a consequence of slab roll-back along active subduction zones. We present new geological and structural data on the Gavorrano antiform, a key sector of the inner northern Apennines. Lying close to the northern Tyrrhenian Sea, it provides clear evidence of Pliocene shortening deformation and magma emplacement. The orientation of σ1 (N50°E - N80°E) derived by fault slip data inversion is consistent with a general ENE –WSW shortening direction. Furthermore, this ENE-trending orientation of σ1 is compatible with the compressive deformation recorded in coeval sedimentary basins. On this basis we suggest that the inner northern Apennines were affected by crustal shortening during the Pliocene. This scenario matches well geophysical data suggesting that since the Late Messinian (6 – 5 Ma) subduction rollback and back-arc extension strongly decreased in the northern Tyrrhenian Sea, while they continued as active processes in the southern Tyrrhenian Sea

Best-fit results from application of a thermo-rheological model for channelized lava flow to high spatial resolution morphological data

The FLOWGO thermo-rheological model links heat loss, core cooling, crystallization, rheology and flow dynamics for lava flowing in a channel. We fit this model to laser altimeter (LIDAR) derived channel width data, as well as effusion rate and flow velocity measurements, to produce a best-fit prediction of thermal and rheological conditions for lava flowing in a ~1.6 km long channel active on Mt. Etna (Italy) on 16th September 2004. Using, as a starting condition for the model, the mean channel width over the first 100 m (6 m) and a depth of 1 m we obtain an initial velocity and instantaneous effusion rate of 0.3–0.6 m/s and ~3 m3/s, respectively. This compares with field- and LIDAR-derived values of 0.4 m/s and 1–4 m3/s. The best fit between model-output and LIDAR-measured channel widths comes from a hybrid run in which the proximal section of the channel is characterised by poorly insulated flow and the medial-distal section by well-insulated flow. This best-fit model implies that flow conditions evolve down-channel, where hot crusts on a free flowing channel maximise heat losses across the proximal section, whereas thick, stable, mature crusts of ′a′a clinker reduce heat losses across the medial-distal section. This results in core cooling per unit distance that decreases from ~0.02–0.015°C m−1 across the proximal section, to ~0.005°C m−1 across the medial-distal section. This produces an increase in core viscosity from ~3800 Pa s at the vent to ~8000 Pa s across the distal section

Fault architecture in the Main Ethiopian Rift and comparison with experimental models: Implications for rift evolution and Nubia-Somalia kinematics

The Main Ethiopian Rift (MER) offers a complete record of the time–space evolution of a continental rift. We have characterized the brittle deformation in different rift sectors through the statistical analysis of a new database of faults obtained from the integration between satellite images and digital elevation models, and implemented with field controls. This analysis has been compared with the results of lithospheric-scale analogue models reproducing the kinematical conditions of orthogonal and oblique rifting. Integration of these approaches suggests substantial differences in fault architecture in the different rift sectors that in turn reflect an along-axis variation of the rift development and southward decrease in rift evolution. The northernmost MER sector is in a mature stage of incipient continental rupture, with deformation localised within the rift floor along discrete tectono-magmatic segments and almost inactive boundary faults. The central MER sector records a transitional stage in which migration of deformation from boundary faults to faults internal to the rift valley is in an incipient phase. The southernmost MER sector is instead in an early continental stage, with the largest part of deformation being accommodated by boundary faults and almost absent internal faults. The MER thus records along its axis the typical evolution of continental rifting, from fault-dominated rift morphology in the early stages of extension toward magma-dominated extension during break-up. The extrapolation of modelling results suggests that a variable rift obliquity contributes to the observed along-axis variations in rift architecture and evolutionary stage, being oblique rifting conditions controlling the MER evolution since its birth in the Late Miocene in relation to a constant post ca. 11 Ma ~ N100°E Nubia–Somalia motion.Published479-4923.2. Tettonica attiva3.3. Geodinamica e struttura dell'interno della TerraJCR Journalreserve

Geology of the Northern Apennines nappe stack on eastern Elba (Italy): new insights on the Neogene orogenic evolution of the Northern Tyrrhenian Sea

We document the tectonic and metamorphic evolution of thrust nappes of the eastern island of Elba. The area exposes a natural cross section of the Northern Apennines hinterland, from the metamorphic basement units to the overlying continent- and ocean-derived nappes. We integrated mapping, analysis of structures and microstructures, and the interpretation of drill core logs with lithostratigraphic, metamorphic, and geochronological constraints, producing a novel geological map of eastern Elba (1:5’000 scale). We show that the area experienced polyphase Oligocene–Pliocene contractional tectonics marked by in-sequence and out-of-sequence thrusting accompanied by folding and overprinted by faulting in the Pliocene. Magmatism occurred during contraction with post-magmatic thrusting ultimately coupling HP-LT and LP-HT units. Drill core logs allow for the first time the reconstruction of the N-dipping character of the Zuccale Fault, which represents the youngest (late Miocene–early Pliocene) large-scale structure in the area

Cp2TiCl2-Catalyzed Photoredox Allylation of Aldehydes with Visible Light

A Barbier-type Cp2TiCl2-mediated (10 mol %) photoredox allylation of aldehydes under irradiation with visible light (blue light-emitting diodes (LEDs), 450 nm) and in the presence of an organic dye (3DPAFIPN, 5 mol %) with allylbromides is described

Multicentre Withinperson Randomised Controlled Trial of 0.5 Mm Versus 1.5 Mm Subcrestal Placement of Dental Implants With Internal Conical Connection: Five-year Post-loading Results

PURPOSE. To assess whether there are any clinical benefits to placing single dental implants either 0.5 or 1.5 mm subcrestally in healed bone crests. MATERIALS AND METHODS. Sixty partially edentulous patients at six centres requiring two single implant-supported crowns had both sites randomly allocated according to a split-mouth design to either 0.5 mm or 1.5 mm subcrestal implant placement; implants in aesthetic areas were submerged for 3 months while those in non-aesthetic areas were not. Provisional acrylic crowns were fitted and replaced with definitive metal-ceramic crowns after 2 months. Patients were followed up to 5 years after loading. Outcome measures were: crown and implant failures, complications, aesthetics assessed using the pink esthetic score (PES), peri-implant marginal bone level changes, and patient prefe-rence, recorded by blinded assessors. RESULTS. Two patients dropped out. There were no statistically significant differences in failure rate (out of 58 patients, four implants failed in the 0.5 mm group versus one in the 1.5 mm group; difference =-5.17%; 95% CI-10.87% to 0.53%; P = 0.250) or complications (out of 58 patients eight complications occurred in eight patients from the 0.5 mm group versus five complications in five patients from the 1.5 mm group (difference =-5.17%; 95% CI-14.01% to 3.67%; P = 0.453) between groups. At 5 years after loading, the mean pink aesthetic scores were 10.89 ± 2.30 and 10.79 ± 2.41 in the 0.5 and 1.5 mm groups, respecti-vely, a difference that was not statistically significant (P = 0.943). Patients from the 0.5 mm group lost on average 0.53 ± 1.43 mm peri-implant marginal bone, and those in the 1.5 mm group lost 0.31 ± 0.98 mm, a statistically significant difference (0.26 mm; 95% CI 0.05 to 0.47; P = 0.016). Patients did not prefer any depth of implant placement over the other. There were no differences in outcomes between centres. CONCLUSIONS. No clinically appreciable differences were noted when placing implants surrounded by at least 1 mm of bone 0.5 mm or 1.5 mm subcrestally. Clinicians are therefore free to choose which strategy they prefer