منابع مشابه
‘ballen Silica’ in Impactites and Magmatic Rocks
Introduction and background: Ballen silica, in the modification of α-quartz (‘ballen quartz’) or α-cristobalite, has been regarded as an impactcharacterstic microscopic feature for decades. The report of ballen silica in impact melt rocks from the Mien impact structure (Sweden; the impact melt rocks were formerly considered as rhyolites) was the first description of ballen silica in impactites ...
متن کاملMicrosampling and Isotopic Analysis of Igneous Rocks: Implications for the Study of Magmatic Systems
Isotopic fingerprinting has long been used to trace magmatic processes and the components that contribute to magmas. Recent technological improvements have provided an opportunity to analyze isotopic compositions on the scale of individual crystals, and consequently to integrate isotopic and geochemical tracing with textural and petrographic observations. It has now become clear that mineral ph...
متن کاملMagmatic evolution of Panama Canal volcanic rocks: A record of arc processes and tectonic change
Volcanic rocks along the Panama Canal present a world-class opportunity to examine the relationship between arc magmatism, tectonic forcing, wet and dry magmas, and volcanic structures. Major and trace element geochemistry of Canal volcanic rocks indicate a significant petrologic transition at 21-25 Ma. Oligocene Bas Obispo Fm. rocks have large negative Nb-Ta anomalies, low HREE, fluid mobile e...
متن کاملGeochemistry of intermediate to siliceous volcanic rocks of the Rooiberg Group, Bushveld Magmatic Province, South Africa
The volcanic Rooiberg Group represents the earliest phase of Bushveld-related magmatism and comprises, in some areas, the floor and roof rocks of the mafic–ultramafic intrusive units of the Bushveld Complex. The lower to middle Dullstroom Formation is composed of two interbedded series of low Ti and high Ti volcanic strata, which are predominantly basaltic andesites. Volcanic units above these ...
متن کاملDetermination of Calcium, Magnesium and Aluminium in Magmatic Rocks after Ultrasonic Leaching by Flame AAS
A method of ultrasonic leaching has been developed for the destructive analysis of magmatic rock samples. This method was applied to determine three new elements, Ca, Mg and Al, in magmatic rock samples. The accuracy of the ultrasonic leaching method (CULM) was tested using standard reference materials (SRMs) and the recovery ratio as K1 = CULM/CSRM was defined. Another recovery ratio, K2, was ...
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ژورنال
عنوان ژورنال: Science
سال: 1902
ISSN: 0036-8075,1095-9203
DOI: 10.1126/science.15.366.32