Chemical and minero-petrographic features of Plio-Pleistocene fine-grained sediments in Calabria, southern Italy

2014 ◽  
Vol 133 (1) ◽  
pp. 101-115 ◽  
Author(s):  
Francesco Perri ◽  
Luigi Borrelli ◽  
Giovanni Gullà ◽  
Salvatore Critelli
Keyword(s):  
Southern Italy ◽  
Fine Grained

Electrical resistivity tomography investigations in the ufita Valley (southern Italy).

2008 ◽  
Vol 51 (1) ◽  
Author(s):  
A. Giocoli ◽  
C. Magrì ◽  
P. Vannoli ◽  
S. Piscitelli ◽  
E. Rizzo ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Electrical Resistivity Tomography ◽  
Southern Italy ◽  
Normal Fault ◽  
Fluvial Sediments ◽  
Resistivity Tomography ◽  
Fine Grained ◽  
Sedimentary Deposits ◽  
Lacustrine Deposits ◽  
Sedimentary Deposit

Several Electrical Resistivity Tomography (ERT) surveys have been carried out to study the subsurface structural and sedimentary settings of the upper Ufita River valley, and to evaluate their efficiency to distinguish the geological boundary between shallow Quaternary sedimentary deposits and clayey bedrock characterized by moderate resistivity contrast. Five shallow ERTs were carried out across a morphological scarp running at the foot of the northeastern slope of the valley. This valley shoulder is characterized by a set of triangular facets, that some authors associated to the presence of a SW-dipping normal fault. The geological studies allow us to interpret the shallow ERTs results obtaining a resistivity range for each Quaternary sedimentary deposit. The tomographies showed the geometrical relationships of alluvial and slope deposits, having a maximum thickness of 30-40 m, and the morphology of the bedrock. The resistivity range obtained for each sedimentary body has been used for calibrating the tomographic results of one 3560m-long deep ERT carried out across the deeper part of the intramountain depression with an investigation depth of about 170 m. The deep resistivity result highlighted the complex alluvial setting, characterized by alternating fine grained lacustrine deposits and coarser gravelly fluvial sediments.

scholarly journals Hydrodynamics in Evaporate-Bearing Fine-Grained Successions Investigated through an Interdisciplinary Approach: A Test Study in Southern Italy—Hydrogeological Behaviour of Heterogeneous Low-Permeability Media

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
E. Petrella ◽  
A. Bucci ◽  
K. Ogata ◽  
A. Zanini ◽  
G. Naclerio ◽  
...  
Keyword(s):  
Southern Italy ◽  
Interdisciplinary Approach ◽  
Flow Conditions ◽  
Hydraulic Connection ◽  
Fine Grained ◽  
Test Study ◽  
Aquifer Systems ◽  
Hydraulic Heterogeneity ◽  
Microbiological Data

Messinian evaporates are widely distributed in the Mediterranean Sea as outcropping sediments in small marginal basins and in marine cores. Progressive filling of subbasins led to the formation of complex aquifer systems in different regions where hypersaline and fresh water coexist and interact in different manner. It also generates a significant diversification of groundwater hydrochemical signature and different microbial communities. In the case study, the hydrogeology and hydrochemistry of the whole system are influenced by good hydraulic connection between the shallower pyroclastic horizon and the underlying evaporate-bearing fine-grained Messinian succession. This is demonstrated by the merge of hydrogeological, chemical, isotopic, and microbiological data. No mixing with deep ascending waters has been observed. As shown by geophysical, hydraulic, and microbiological investigations, the hydraulic heterogeneity of the Messinian bedrock, mainly due to karstified evaporitic interstrata/lenses, causes the hydraulic head to significantly vary with depth. Somewhere, the head increases with the depth’s increase and artesian flow conditions are locally observed. Moreover, the metagenomic investigations demonstrated the existence of a poor hydraulic connection within the evaporate-bearing fine-grained succession at metric and decametric scales, therefore leading to a patchwork of geochemical (and microbiological) subenvironments.

A new–old approach for shallow landslide analysis and susceptibility zoning in fine-grained weathered soils of southern Italy

Geomorphology ◽  
2015 ◽  
Vol 241 ◽  
pp. 371-381 ◽  
Author(s):  
Leonardo Cascini ◽  
Mariantonietta Ciurleo ◽  
Silvio Di Nocera ◽  
Giovanni Gullà
Keyword(s):  
Southern Italy ◽  
Shallow Landslide ◽  
Fine Grained ◽  
Weathered Soils

Fault rocks within the blueschist metabasalts of the Diamante–Terranova unit (southern Italy): potential fossil record of intermediate-depth subduction earthquakes

2019 ◽  
Vol 156 (10) ◽  
pp. 1771-1782 ◽  
Author(s):  
Stefano Vitale ◽  
Lorenzo Fedele ◽  
Francesco D’Assisi Tramparulo ◽  
Ernesto Paolo Prinzi
Keyword(s):  
Fossil Record ◽  
Southern Italy ◽  
Seismic Events ◽  
Molten Material ◽  
Diagnostic Features ◽  
Fault Rocks ◽  
Intermediate Depth ◽  
Fine Grained ◽  
Selective Preservation ◽  
Frictional Melting

AbstractWe report the first evidence of fault rocks (FRs) developed during high-pressure/low-temperature (HP/LT) subduction-related metamorphism, within quartz+epidote pods embedded in the glaucophane–lawsonite-bearing ophiolitic metabasalts of the Diamante–Terranova unit (Calabria, Italy). FRs occur as relic injections appearing as thin dark seams, locally showing an internal foliation characterized by tabular, curvilinear and meander-like shapes, and consist of very fine grains of glaucophane and titanite, locally including survivor clasts of epidote and lawsonite. Some boudinaged veins show glaucophane fibres in the boudin necks, marking a clear HP/LT syn-metamorphic origin at c. 30 km depth. The injected FRs can be alternatively interpreted either as pseudotachylytes or as fluidized ultracataclasites. Although subsequent recrystallization largely obliterated primary diagnostic features, the occurrence of (i) different-coloured flow streaks, characterized by alternating layers of glaucophane and titanite, (ii) well-developed flow folds and (iii) corroded epidote survivor crystals could indicate a viscous flow of molten material characterized by a non-uniform chemical composition. With this in mind, we support the hypothesis that these fine-grained veins were originally pseudotachylytes generated by the frictional melting of the glaucophane-rich layers of the Diamante–Terranova metabasalts, likely related to seismic events occurring during the Eocene along thrust faults within the subducting oceanic Ligurian lithosphere. The lack of evidence for pseudotachylyte relics in the metabasalt source rock argues for a selective preservation, largely dependent on the efficient mechanical shielding action of the stiffer quartz+epidote pods.

Application of an image management system in microscopy

1992 ◽  
Vol 50 (2) ◽  
pp. 1052-1053
Author(s):  
Richard S. Chemock
Keyword(s):  
Data Storage ◽  
Cost Savings ◽  
Image Data ◽  
Analytical Techniques ◽  
Operational Mode ◽  
Fine Grained ◽  
Image Recording ◽  
Primary Output ◽  
Capacity Data ◽  
Image Management System

One of the most common tasks in a typical analysis lab is the recording of images. Many analytical techniques (TEM, SEM, and metallography for example) produce images as their primary output. Until recently, the most common method of recording images was by using film. Current PS/2R systems offer very large capacity data storage devices and high resolution displays, making it practical to work with analytical images on PS/2s, thereby sidestepping the traditional film and darkroom steps. This change in operational mode offers many benefits: cost savings, throughput, archiving and searching capabilities as well as direct incorporation of the image data into reports.The conventional way to record images involves film, either sheet film (with its associated wet chemistry) for TEM or PolaroidR film for SEM and light microscopy. Although film is inconvenient, it does have the highest quality of all available image recording techniques. The fine grained film used for TEM has a resolution that would exceed a 4096x4096x16 bit digital image.

Use of fractals to describe microstructures of porous thick-film platinum electrodes

1992 ◽  
Vol 50 (1) ◽  
pp. 314-315
Author(s):  
Steven D. Toteda
Keyword(s):  
Fractal Dimension ◽  
Power Plants ◽  
Electrical Response ◽  
Cubic Phase ◽  
Platinum Electrodes ◽  
Fine Grained ◽  
Impedance Response ◽  
Platinum Particles ◽  
Energy Surfaces ◽  
Highly Porous

Zirconia oxygen sensors, in such applications as power plants and automobiles, generally utilize platinum electrodes for the catalytic reaction of dissociating O2 at the surface. The microstructure of the platinum electrode defines the resulting electrical response. The electrode must be porous enough to allow the oxygen to reach the zirconia surface while still remaining electrically continuous. At low sintering temperatures, the platinum is highly porous and fine grained. The platinum particles sinter together as the firing temperatures are increased. As the sintering temperatures are raised even further, the surface of the platinum begins to facet with lower energy surfaces. These microstructural changes can be seen in Figures 1 and 2, but the goal of the work is to characterize the microstructure by its fractal dimension and then relate the fractal dimension to the electrical response. The sensors were fabricated from zirconia powder stabilized in the cubic phase with 8 mol% percent yttria. Each substrate was sintered for 14 hours at 1200°C. The resulting zirconia pellets, 13mm in diameter and 2mm in thickness, were roughly 97 to 98 percent of theoretical density. The Engelhard #6082 platinum paste was applied to the zirconia disks after they were mechanically polished ( diamond). The electrodes were then sintered at temperatures ranging from 600°C to 1000°C. Each sensor was tested to determine the impedance response from 1Hz to 5,000Hz. These frequencies correspond to the electrode at the test temperature of 600°C.

Amorphous silica coating on α-alumina particles

1995 ◽  
Vol 53 ◽  
pp. 210-211
Author(s):  
J. W. Mellowes ◽  
C. M. Chun ◽  
I. A. Aksay
Keyword(s):  
Amorphous Silica ◽  
Heterogeneous Nucleation ◽  
Homogeneous Nucleation ◽  
Silica Coating ◽  
Full Density ◽  
Optimal Conditions ◽  
Fine Grained ◽  
Alumina Particles ◽  
Complete Mullitization ◽  
Powder Compacts

Mullite (3Al2O32SiO2) can be fabricated by transient viscous sintering using composite particles which consist of inner cores of a-alumina and outer coatings of amorphous silica. Powder compacts prepared with these particles are sintered to almost full density at relatively low temperatures (~1300°C) and converted to dense, fine-grained mullite at higher temperatures (>1500°C) by reaction between the alumina core and the silica coating. In order to achieve complete mullitization, optimal conditions for coating alumina particles with amorphous silica must be achieved. Formation of amorphous silica can occur in solution (homogeneous nucleation) or on the surface of alumina (heterogeneous nucleation) depending on the degree of supersaturation of the solvent in which the particles are immersed. Successful coating of silica on alumina occurs when heterogeneous nucleation is promoted and homogeneous nucleation is suppressed. Therefore, one key to successful coating is an understanding of the factors such as pH and concentration that control silica nucleation in aqueous solutions. In the current work, we use TEM to determine the optimal conditions of this processing.

Interfacial structures of dissimilar materials joined by capacitor-discharge welding

1994 ◽  
Vol 52 ◽  
pp. 534-535
Author(s):  
C. P. Doğan ◽  
R. D. Wilson ◽  
J. A. Hawk
Keyword(s):  
Rapid Solidification ◽  
Fusion Zone ◽  
Dissimilar Materials ◽  
Solidification Process ◽  
Weld Interface ◽  
Capacitor Discharge ◽  
Fine Grained ◽  
Iron Aluminum ◽  
Conductive Ceramics ◽  
Capacitor Discharge Welding

Capacitor Discharge Welding is a rapid solidification technique for joining conductive materials that results in a narrow fusion zone and almost no heat affected zone. As a result, the microstructures and properties of the bulk materials are essentially continuous across the weld interface. During the joining process, one of the materials to be joined acts as the anode and the other acts as the cathode. The anode and cathode are brought together with a concomitant discharge of a capacitor bank, creating an arc which melts the materials at the joining surfaces and welds them together (Fig. 1). As the electrodes impact, the arc is extinguished, and the molten interface cools at rates that can exceed 106 K/s. This process results in reduced porosity in the fusion zone, a fine-grained weldment, and a reduced tendency for hot cracking.At the U.S. Bureau of Mines, we are currently examining the possibilities of using capacitor discharge welding to join dissimilar metals, metals to intermetallics, and metals to conductive ceramics. In this particular study, we will examine the microstructural characteristics of iron-aluminum welds in detail, focussing our attention primarily on interfaces produced during the rapid solidification process.

TEM/AEM characterization of fine-grained clay minerals in very-low-grade rocks: Evaluation of contamination by empa involving celadonite family minerals

1996 ◽  
Vol 54 ◽  
pp. 694-695
Author(s):  
Gejing Li ◽  
D. R. Peacor ◽  
D. S. Coombs ◽  
Y. Kawachi
Keyword(s):  
Electron Microscopy ◽  
Volcanic Rocks ◽  
Analytical Electron Microscopy ◽  
Metamorphic Rocks ◽  
New Mineral ◽  
Chemical Compositions ◽  
Low Grade ◽  
Fine Grained ◽  
Depth Analysis ◽  
Mineral Aggregates

Recent advances in transmission electron microscopy (TEM) and analytical electron microscopy (AEM) have led to many new insights into the structural and chemical characteristics of very finegrained, optically homogeneous mineral aggregates in sedimentary and very low-grade metamorphic rocks. Chemical compositions obtained by electron microprobe analysis (EMPA) on such materials have been shown by TEM/AEM to result from beam overlap on contaminant phases on a scale below resolution of EMPA, which in turn can lead to errors in interpretation and determination of formation conditions. Here we present an in-depth analysis of the relation between AEM and EMPA data, which leads also to the definition of new mineral phases, and demonstrate the resolution power of AEM relative to EMPA in investigations of very fine-grained mineral aggregates in sedimentary and very low-grade metamorphic rocks.Celadonite, having end-member composition KMgFe3+Si4O10(OH)2, and with minor substitution of Fe2+ for Mg and Al for Fe3+ on octahedral sites, is a fine-grained mica widespread in volcanic rocks and volcaniclastic sediments which have undergone low-temperature alteration in the oceanic crust and in burial metamorphic sequences.

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