Results 231 to 240 of about 18,181 (272)

The Cenozoic alkaline magmatism in central-northern Madagascar: a brief overview

Periodico di Mineralogia, 2007
The Cenozoic volcanic rocks of Madagascar were emplaced as lavas, pyroclastic rocks, dykes, and plugs, and range in composition from olivine melilitites, basanites and alkali basalts, to phonolites, trachytes and rhyolites. The ultrabasic- basic lithologies are dominant, in particular basanites and tephrites, with less abundant, mildly evolved ...
MELLUSO, LEONE, MORRA, VINCENZO, BROTZU, PIETRO, FRANCIOSI, LUIGI, C. GRIFA, M. LUSTRINO, P. MORBIDELLI, H. RIZIKY, M. VINCENT   +8 more
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Transtension and alkaline magmatism of the Romanche Fracture Zone

Geotectonics, 2008
New magnetometric, petrological, and geochemical data on basalts from the central Romanche Fracture Zone (FZ) allow us to classify these rocks into two groups. The igneous rocks from the active part of the fracture zone that experienced transtension are referred to as alkaline rocks.
G. L. Kashintsev, A. A. Shreider, V. I. Maksimochkin, A. A. Bulychev, D. A. Gilod   +4 more
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SALINE DEPOSITS AND ALKALINE MAGMATISM: A GENETIC MODEL

Journal of Petroleum Geology, 1990
The temporal and spatical coincidence of saline deposits with rifting and alkaline magmatism is now widely accepted. The congruency of these three phenomena implies, logically, their trilateral genetic inter‐relationship. Conventional models for the formation of saline deposits, i.e. the “evaporation process”, cannot be properly applied to giant saline
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Tertiary alkaline magmatism in East Greenland: a review

Geological Society, London, Special Publications, 1987
SummaryThe Tertiary alkaline magmatism in E Greenland is the result of the processes related to the continental break-up of the N Atlantic in the Lower Tertiary. The alkaline rocks are divided into three groups: A, inland alkaline lavas, dykes and intrusive complexes of nephelinitic parentage; B, mildly-alkaline to nephelinitic mafic lavas and dykes ...
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Alkaline Earth Element Partitioning in Simplified Magmatic Systems

2007
Trace element distributions between mineral and melt phases have proven to be important recorders of igneous differentiation histories, but this utility depends on thorough understanding of their partitioning behavior. We propose a theory for crystal-melt trace element partitioning that considers the energetic consequences of crystal-lattice strain, of
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Baddeleyite: A promising geochronometer for alkaline and basic magmatism

Petrology, 2006
The paper is devoted to the history of the discovery, petrological and mineralogical characterization, and U-Pb dating of baddeleyite ZrO2, which was separated from various Archean, Proterozoic, and Paleozoic rocks from Fennoscandia. The morphology of this mineral and its U-Pb age values were examined in the Archean carbonatites (2613 ± 18 Ma) of ...
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Diversity of magmatism, hydrothermal processes and microbial interactions at mid-ocean ridges

Nature Reviews Earth & Environment, 2022
Gretchen Früh-Green, D S Kelley, Marvin D Lilley   +2 more
exaly  

Natural ultrabasic-alkaline magmatic glasses

International Geology Review, 1969
A.G. Zhabin, V.S. Gladkikh, N.S. Samsonova   +2 more
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Rifts, paleorifts, rifted margins, anorogenic and alkaline magmatism

2010
The term “rift” was introduced, in 1896, by Gregory for a structural graben in Africa (now the Gregory Rift), then for the entire continental system of grabens of which this was a part (the East African Rift system). Since then, until the onset of plate tectonics in 1968, “riftology” became an established branch of geotectonics and a fairly mature one ...
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Alkaline Magmatism in the Eastern Ghat Belt - A Critique

Journal Geological Society of India, 1993
Abstract Almost all the feldspaihoidal alkaline complexs of the Eastern Ghat granulite belt are virtually restricted to its western margin, arid are significantly confined to the junction zone between the catonic and mobile belt regions. The presence of subordinate amounts of quartz syenite in preponderantly nephe1ine syenite plutons is ...
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