Results 51 to 60 of about 7,121 (239)
Geostandards and Geoanalytical Research, EarlyView.Key Points An analytical strategy for determining boron isotope ratios in Ca‐amphiboles using LA‐MC‐ICP‐MS is presented. Accurate δ11B results can be achieved using the USGS BHVO‐2G glass as the calibrating reference material. Two proposed Ca‐amphibole RMs exhibit good homogeneity with δ11B intermediate measurement precision of 2.86‰ and 3.96 (2s). The
Enrico Cannaò +3 more
wiley +1 more source
Origin of Ophiolitic Peridotites
Journal of Geography (Chigaku Zasshi), 1989 Origin of spinel peridotites of upper mantle derivation, especially that of ophiolitic peridotites, is discussed mainly on the basis of compositional relationship between olivine (Fo content) and chromian spinel (Cr/(Cr+Al) atomic ratio=Cr* ratio). Spinel peridotites are distributed in a relatively narrow band, the olivine-spinel mantle array, on the ...
openaire +3 more sources
Geostandards and Geoanalytical Research, EarlyView.Key Points DMA‐80 analyses are inaccurate and imprecise when crystalline rocks have Hg < 10 ng g‐1. DMA‐80 cannot desorb all Hg from mafic‐ultramafic rocks. CV‐AFS analyses are more accurate and precise, even at ultra‐low Hg mass fractions (< 1 pg g‐1).
Francesco Narduzzi +10 more
wiley +1 more source
Tracking the evolution of magmas from heterogeneous mantle sources to eruption [PDF]
arXiv, 2020 This contribution reviews the effects of source heterogeneities, melt-rock reactions and intracrustal differentiation on magma chemistry across mid-ocean ridges, intraplate settings and subduction zones using experimental studies and natural data. We compare melting behaviors of pyroxenites and peridotites and their relative contributions to magmas as ...
arxiv
Evidence for Phosphate Metasomatism in an Olivine‐Rich Achondrites
Meteoritics &Planetary Science, EarlyView.Abstract Brachinites, brachinite‐like achondrites (BLA), and other similar primitive achondrites offer important constraints on differentiation processes of the earliest formed planetesimals, as they quenched amidst early differentiation processes on their parent body. Geochemical data for all major mineral phases in two previously poorly characterized
Robert W. Nicklas +5 more
wiley +1 more source
EFFECT OF WEATHERING GRADE ON MECHANICAL PROPERTIES O ROCKS FROM RANAU, SABAH [PDF]
Earth Science Malaysia, 2017 A study of effect of weathering grade on mechanical properties of rocks have been conducted on selected rock samples from Crocker Formation, Trusmadi Formation and peridotite on weathering grade II to V.
Hennie Fitria Wulandary
doaj +1 more source
Planetary Felsic Crust Formation at Shallow Depth [PDF]
arXiv, 2020 Current theories suggest that on Earth and, possibly, on other terrestrial planets early in their history, the first continental crust may has been produced by direct melting of hydrated peridotite. However, the conditions, mechanisms and necessary ingredients of such production remain elusive.
arxiv
On a Diamantiferous Peridotite, and the Genesis of the Diamond [PDF]
Scientific American, 1886 The discovery of diamonds at Kimberley, South Africa, has proved to be a matter, not only of commercial, but of much geological interest. The conditions under which diamonds here occur are unlike those of any other known locality, and are worthy of special attention.
openaire +3 more sources
Hydrous Asthenosphere Underneath the Northern Pannonian Basin
Terra Nova, EarlyView.ABSTRACT This study reveals the structural hydroxyl content in clinopyroxenes of three cumulate xenoliths from the Nógrád‐Gömör/Novohrad‐Gemer Volcanic Field (northern Pannonian Basin), with values ranging from 275 to 384 ppm. Based on these data, the water content of the equilibrium parental alkali basaltic melt was estimated to be between 1.5 and 2.1
Levente Patkó +6 more
wiley +1 more source
Frictional melting of peridotite and seismic slip
Journal of Geophysical Research: Solid Earth, 2009 The evolution of the frictional strength along a fault at seismic slip rates (about 1 m/s) is a key factor controlling earthquake mechanics. At mantle depths, friction‐induced melting and melt lubrication may influence earthquake slip and seismological data.
Del Gaudio +13 more
openaire +3 more sources