Search results for " basalt"
showing 10 items of 42 documents
A review on basalt fibre and its composites
2015
Abstract In recent years, both industrial and academic world are focussing their attention toward the development of sustainable composites, reinforced with natural fibres. In particular, among the natural fibres (i.e. animal, vegetable or mineral) that can be used as reinforcement, the basalt ones represent the most interesting for their properties. The aim of this review is to illustrate the results of research on this topical subject. In the introduction, mechanical, thermal and chemical properties of basalt fibre have been reviewed. Moreover, its main manufacturing technologies have been described. Then, the effect of using this mineral fibre as reinforcement of different matrices as po…
Petrology and geochemistry of submarine volcanism in the Sicily Channel Rift
2006
Submarine magmatism in the Sicily Channel Rift began in the early Pliocene and lasted until almost 200 yr ago. We present here petrological and geochemical data on volcanic rocks dredged from Graham and Nameless banks and Pantelleria seamounts in the Pelagian sector of the Sicily Channel Rift. Petrological evidence suggests that the ascent of magmas to the surface was relatively rapid, probably through channels superimposed over the major tectonic discontinuities of the Rift. Major and trace element data indicate an ocean island basalt affinity for Graham and Nameless bank alkaline lavas and a depleted tholeiitic signature for one Pantelleria seamount, which had a shallower mantle source. S…
Amygdaloidal basalts: Isotopic and petrographic evidence for non-diagenetic crustal source of carbonate inclusions
1980
Even though carbonate amygdules in volcanics are generally assumed to be diagenetic in origin, the authors are of the opinion that almost all carbonate inclusions in the investigated amygdaloidal volcanic rocks from Sicily (Italy), Pindos (Greece) and Bohemia (Czechoslovakia), have a different origin. On the basis of a mineralogical, petrological and geochemical study these “amygdules” are interpreted as being remains ofmagmatic incorporation of carbonate. Therefore, the identification of carbonate globules in volcanics purely on field observations, is inadequate to distinguish true amygdules from carbonate assimilation remnants. A nomenclature of the various types of inclusions is proposed…
Transition from mildly-tholeiitic to calc-alkaline suite: the case of Chichontepec volcanic centre, El Salvador, Central America
1998
Abstract The Chichontepec volcano is a Plio-Pleistocene composite volcano that erupted lavas ranging from high-alumina basalts to dacites. It experienced a caldera-forming paroxysmal eruption during the early Pleistocene. Pre-caldera lavas are mildly tholeiitic and they evolved mainly by low pressure crystal fractionation, notwithstanding the fact that most mafic lavas (low-MgO high-alumina basalts) retain traces of polybaric evolution. Conversely, post-caldera lavas, which are mainly pyroxene andesites, are clearly calc-alkaline, having evolved by open-system crystal fractionation. Sr–Nd isotopic data and trace elements characteristics indicate that the same mantle source was involved in t…
Behavior in compression of concrete cylinders externally wrapped with basalt fibers
2015
Abstract This paper gives additional information on the use of new class of composites constituted by Basalt Fiber Reinforced Polymer (BFRP) bonded with epoxy resin to concrete specimens as an alternative confinement material for compressed concrete members with respect to carbon or glass fibers. From the experimental point of view, concrete cylinders are wrapped with continuous fibers, in the form of sheets, applying both full and partial discrete wrapping with BFRP straps, and then tested in compression. For comparison, few other concrete cylinders are wrapped with Carbon Fiber Reinforced Polymer (CFRP) sheets and tested in compression. The number and type of plies (full or partial wrappi…
On the mechanical behavior of BFRP to aluminum AA6086 mixed joints
2013
The aim of this work is to analyze the possibility to join aluminum alloy AA6086 and composite laminates reinforced with basalt fibers, an innovative material which use is growing in several applications as an alternative to glass fibers. To this goal, three joining techniques were investigated: mechanical by Self Piercing Riveting (in the next called SPR), adhesive by co-curing technique and mixed in which the joining techniques (i.e. adhesive and mechanical) were combined. Two manufacturing technologies (i.e. hand lay-up and vacuum bagging) were used both to produce composite substrates and to realize co-curing adhesion between the substrates to be joined. Mixed joints were realized by in…
δ30Si and δ29Si Determinations on USGS BHVO-1 and BHVO-2 Reference Materials with a New Configuration on a Nu Plasma Multi-Collector ICP-MS
2008
We report silicon isotopic determinations for USGS rock reference materials BHVO-1 and BHVO-2 using a Nu Plasma multi-collector (MC)-ICP-MS, upgraded with a new adjustable entrance slit, to obtain medium resolution, as well as a stronger primary pump and newly designed sampler and skimmer cones ("B" cones). These settings, combined with the use of collector slits, allowed a resolution to be reached that was sufficient to overcome the (NO)-N-14-O-16 and N-14(2) interferences overlying the Si-30 and the Si-28 peaks, respectively, in an earlier set-up. This enabled accurate measurement of both delta Si-30 and delta Si-29. The delta value is expressed in per mil variation relative to the NBS 28…
The Magmatic to Hydrothermal Evolution of the Intrusive Mont Saint-Hilaire Complex: Insights into the Late-stage Evolution of Peralkaline Rocks
2017
The Cretaceous Mont Saint-Hilaire complex (Quebec, Canada) comprises three major rock units that were emplaced in the following sequence: (I) gabbros; (II) diorites; (III) diverse partly agpaitic foid syenites. The major element compositions of the rock-forming minerals, age-corrected Nd and oxygen isotope data for mineral separates and trace element data of Fe-Mg silicates from the various lithologies imply a common source for all units. The distribution of the rare earth elements in clinopyroxene from the gabbros indicates an ocean island basalt type composition for the parental magma. Gabbros record temperatures of 1200 to 800 degrees C, variable silica activities between 0 center dot 7 …
Volatiles and trace elements content in melt inclusions from the zoned Green Tuff ignimbrite (Pantelleria, Sicily): petrological inferences
2018
International audience; The island of Pantelleria is one of the best known localities of bimodal mafic-felsic magmatism (alkali basalt and trachyte-pantellerite). Among the felsic rocks, the coexistence in a single eruption of products of both trachyte and pantellerite compositions is limited to few occurrences, the Green Tuff (GT) ignimbrite being one of these. The GT is compositionally zoned from pantellerite (70.1 wt% SiO2, mol Na+K/Al = 1.86, 1871 ppm Zr) at the base to crystal-rich (>30 vol%) comenditic trachyte (63.4 wt% SiO2, mol Na+K/Al = 1.10, 265 ppm Zr) at the top, although the pantellertic compositions dominate the erupted volume. We present here new data on melt inclusions (MIs…
Constraints on the Cretaceous thermal event in the Transantarctic Mountains from alteration processes in Ferrar flood basalts
1999
Abstract K–Ar and 40 Ar/ 39 Ar incremental-heating analyses on apophyllite formed during hydrothermal alteration of volcanic rocks from the Ferrar Supergroup in North Victoria Land, Antarctica, provide strong evidence for hydrothermal events during mid-Cretaceous time. A last event has been dated at 96.7±0.6 Ma. Variable older ages between 112 and 125 Ma are interpreted as mixed ages of hydrothermal events or may be caused by disturbances of the Ar–Ar system. The Rb–Sr isotope system of the apophyllites is not applicable to dating because a large portion of the Sr is radiogenic and because of Rb-mobility in the crystal structure. Secondary mineralogy suggests a temperature for alteration be…