This paper reports the first example of fault mirrors developed in an unusual protolith, consisting of tourmaline crystals with interstitial goethite. The deformation mechanisms active in the fault ...zone have been investigated from the outcrop to the nanoscale, aiming to identify possible traces of frictional heating at seismic slip rate, as observed for other fault mirrors in different protoliths. The investigation revealed the superposition of two main deformational stages. The first was dominated by brittle processes and produced a cataclastic/ultracataclastic principal slip zone, a few mm thick; the second was associated with seismic slip and produced a sharp discontinuity (the principal slip surface) within the cataclastic/ultracataclastic zone. The mirror-like coating, a few microns thick, occurs on the principal slip surface, and is characterized by 1) absence of interstitial goethite; 2) occurrence of truncated tourmaline crystals; 3) highly variable grain size, from 200 μm to 200 nm; 4) tourmaline close packing with interlobate grain boundaries, and 5) tourmaline random crystallographic orientation.
Micro and nanostructural investigations indicate the occurrence of thermally-activated processes, involving both interstitial goethite and tourmaline. In particular, close to the principal slip surface, goethite is completely decomposed, and produced an amorphous porous material, with local topotactic recrystallization of hematite. Tourmaline clasts are typically characterized by strongly lobate boundaries, indicative of reaction and partial decomposition at grain boundaries. TEM observations revealed the occurrence of tourmaline nanograins, a few tens of nm in size, characterized by rounded shape and fading amorphous boundaries, that cannot be obtained by brittle processes. Lastly, the peculiar interlobate microstructure of the mirror surface is interpreted as the result of grain boundary recrystallization processes taking place by deformation at high-T conditions. Our results show that tourmaline fault mirrors recorded localized high-T processes triggered by frictional heating and can be therefore considered as reliable traces of ancient earthquakes.
•Mirror faults are reliable traces of ancient earthquakes.•Tourmaline mirror faults are described for the first time, down to the nanoscale.•We observed mineral decomposition, nanograins and grain boundary recrystallization.•Mineral reactions are triggered by frictional heating on the slip surface.
The dataset presented in this article is used in the Quaternary Science Review research article “Evaluating the geogenic CO2 flux from geothermal areas by analysing Quaternary travertine masses. New ...data from western Central Italy and review of previous CO2 flux data” 1. The present data article reports the physical properties and new compositional data of 86 travertine samples from Rapolano, Canino and Tivoli travertine deposits (Italy). The dataset include the following parameters: mass, volume, porosity, bulk density, CaCO3 content and insoluble fraction. The dataset is integrated with the photographic documentation of the sampling areas, the location and the stratigraphic position of each sample.
•Offshore sea-water recharges coastal, sulhpurous, thermal springs.•A deep hydrothermal-convection system, controlled by fault zones, is discovered.•The integration of methodologies represents a ...key-factor for geothermal exploration.
Carbonate aquifers in foreland tectonic settings can host important thermal springs although located in areas commonly not characterized by regional high heat flow values. In these cases, when thermal springs are located close or along the coastlines the subaerial and/or submarine thermal springs constitute the outflow of marine groundwater, flowing through localized fractures and karsitic rock-volumes. This is the case of springs occurring along the south-easternmost portion of the Apulia region (Southern Italy) where few sulphurous and warm waters (22–33°C) outflow in partially submerged caves located along the shoreline, thus supplying the historical spas of Santa Cesarea Terme. Here, with the aim to define the origin of the thermal fluids and their deep path, we carried out the geo-structural survey of the area and detailed hydrogeological and geochemical analyses of the thermal spring fluids. In particular, the isotopes δ18O, δD, 13C in DIC, 34Ssulphate, 34Ssulphide, 3He/4He ratio and 13C in CO2 were used to define the origin of the thermal water and the recharge mechanism of the geothermal system while the isotopes 3H and 14C were determined for estimating the age of the thermal waters, resulting in older than roughly twenty thousands years BP. The results indicate that the thermal springs are fed by marine water, having reached Santa Cesarea Terme through a localized fracture network. This affects the evaporitic and carbonatic rocks that characterize the substratum of the Adriatic Sea in the offshore.
The Larderello geothermal field is located in the inner Northern Apennines (southern Tuscany), an area which has been affected by extensional tectonics since the Early–Middle Miocene. The structure ...of the Larderello field is characterised by NW-trending, NE-dipping Pliocene to Present normal faults. Their geometry down to depths of 4–5 km is constrained by field, borehole, and reflection seismic data. An association between extensional structures and heat flow maxima (up to 1000 mW/m
2) is recognisable from detailed surface heat flow mapping. In order to investigate the relationships among extensional structures and heat flow, subsurface isotherms were traced, subject to borehole control, along variously oriented geological cross-sections. The isotherms show vertical displacements associated with the recent normal faults and related deformation zones, which reach the brittle/ductile transition. Estimates of the relative importance of convective and conductive components of heat flow suggest that fluid circulation is particularly important in correspondence with the normal faults, accounting for the correlation between isotherm perturbations and extensional structures. In this view, extensional shear zones are interpreted as the main structural pathways for the flow of hot geothermal fluids.
Objectives – We present the results of a preliminary, open‐label trial to evaluate the efficacy and tolerability of oxcarbazepine in postherpetic neuralgia (PHN) unresponsive to treatment with ...antiepileptic drugs (carbamazepine and gabapentin) and local anesthetic blocks.
Materials and methods – Twenty‐four patients were treated with oxcarbazepine monotherapy for 8 weeks. Starting dose was 150 mg/day, subsequently increased by 150 mg/day every 2 days until a maintenance dose of 900 mg/day. Pain was assessed using a visual analog scale (VAS).
Results – There was a significant decrease in the mean VAS score following 8 weeks of treatment (Δ = 5.33; pairedt‐test: P < 0.0001) compared with baseline. Oxcarbazepine was effective from the first week of treatment. There was a significant reduction in allodynia, leading to improvements in patients’ functioning and quality of life. Oxcarbazepine was generally well tolerated.
Conclusion – Oxcarbazepine appears to be a promising alternative monotherapeutic approach for patients affected by PHN.
Monitoring resource availability along Cloud-IoT networks in a lightweight and fault-resilient manner is a challenging research problem due to scarce resource availability, infrastructure dynamics, ...and platform heterogeneity. In this article, we illustrate a thorough experimental assessment of a self-organising and fault-tolerant monitoring service, FogMon, especially targeting Cloud-IoT settings and capable of probing hardware resource, latency and bandwidth. The assessment is carried out over networks made up of 20 to 40 nodes across two testbeds within the Fed4Fire+ federation. As a result of the assessment, we agilely improved and refined FogMon into FogMon2, which settles at TRL5 and improves on monitoring accuracy and fault-resiliency. Experimental results show how FogMon2 can promptly and suitably handle different types of infrastructure failure, with an average relative error of 10% on measurements and limited footprint on hardware and network resources.
•Lightweight, self-organising and fault-tolerant Cloud-IoT infrastructure monitoring•Agile refinement, assessment and release of a Cloud-IoT monitoring service at TRL5•Experimental assessment in industrially relevant settings over federated resources•Tools for assessing self-organising capabilities against different types of failure
This paper deals with the lateral segmentation (crustal boudinage) and exhumation of the metamorphic units in the hinterland of the Northern Apennines during the Late Miocene extension. The study ...area (Mt. Leoni area) is part of the Middle Tuscan Ridge, a regional morpho-tectonic feature in which the deepest tectonic units of the Northern Apennines are broadly exposed. Crustal seismic profiles and deep boreholes indicate that the Middle Tuscan Ridge coincides with the outcropping part of a laterally discontinuous geological body, mainly made up of HP-LT and greenschist facies metamorphic units. Extensional detachments characterised by top-to-the-East sense of shear and staircase geometry produced the lateral segmentation of the metamorphic units. Their activity can be ascribed to Late Tortonian–Late Messinian times. Geometry and kinematics of the extensional detachments have been compared with the Miocene extensional structures developed at shallow depths in the overthickened crust of the Northern Apennines, allowing understanding of the extensional tectonic evolution which reorganised the hinterland Northern Apennines collisional belt.
PDF
