نتایج جستجو برای: acidic magma

تعداد نتایج: 41771  

Journal: :Open Chemistry 2022

Abstract Variable single and/or swarms of post-granitic dikes are widespread at Gabal Serbal, Southwestern Sinai, Egypt. The present article aims to identify and discriminate these multiphase through detailed geological, petrographical, geochemical examinations. These classified into two subphases: (1) acidic (porphyritic dacite, microgranite, granophyre, alkaline granophyre dikes); (2) basic (...

2007
Patrick J. Shamberger Michael O. Garcia

Geochemical modeling of magma mixing allows for evaluation of volumes of magma storage reservoirs and magma plumbing configurations. A new analytical expression is derived for a simple two-component box-mixing model describing the proportions of mixing components in erupted lavas as a function of time. Four versions of this model are applied to a mixing trend spanning episodes 3–31 of Kilauea V...

2000
James Brophy

Introduction In the following chapters we will find that nearly all of the varied aspects of volcanism are either directly or indirectly controlled by the chemical composition of magma and the rate at which it cools and solidifies. If you are to understand and appreciate subsequent discussions of volcanoes and related volcanic phenomena, it is essential that you have a good grasp of the basic c...

2004
LORELLA FRANCALANCI GARETH R. DAVIES WIM LUSTENHOUWER SIMONE TOMMASINI PAUL R. D. MASON SANDRO CONTICELLI

Over the last several hundred years, Stromboli has been characterized by steady-state Strombolian activity. The volcanic products are dominated by degassed and highly porphyritic (HP-magma) black scoria bombs, lapilli and lava flows of basaltic shoshonitic composition. Periodically (about one to three events per year), more energetic explosive eruptions also eject light coloured volatile-rich p...

2002
A. Barmin O. Melnik R.S.J. Sparks

Lava dome eruptions commonly display fairly regular alternations between periods of high activity and periods of low or no activity. The time scale for these alternations is typically months to several years. Here we develop a generic model of magma discharge through a conduit from an open-system magma chamber with continuous replenishment. The model takes account of the principal controls on f...

2012
Guilherme A. R. Gualda Ayla S. Pamukcu Mark S. Ghiorso Alfred T. Anderson Stephen R. Sutton Mark L. Rivers

Supereruptions violently transfer huge amounts (100 s-1000 s km(3)) of magma to the surface in a matter of days and testify to the existence of giant pools of magma at depth. The longevity of these giant magma bodies is of significant scientific and societal interest. Radiometric data on whole rocks, glasses, feldspar and zircon crystals have been used to suggest that the Bishop Tuff giant magm...

The Alvand complex (Hamedan province) comprises several bodies ranging from acidic to intermediate and basic compositions intruded in the regional metamorphic sequence of the area (the Hamedan phyllites) during various magmatic episodes in Jurassic. In northern part of the complex (the Cheshmeh-ghasaban area) there are some outcrops of hornblende gabbro and olivine gabbronorite. The olivine-gab...

Journal: :Geosciences 2021

The Tuscany Magmatic Province consists of a Miocene to Pleistocene association wide variety rock types, including peraluminous crustal anatectic granites and rhyolites, calcalkaline shoshonitic suites ultrapotassic lamproites. In addition the magma types already recognised, occurrence new, distinct type at Capraia Elba islands in mafic enclaves San Vincenzo rhyolites has been suggested by recen...

2018
Tobias Mattsson Steffi Burchardt Bjarne S. G. Almqvist Erika Ronchin

Felsic magma commonly pools within shallow mushroom-shaped magmatic intrusions, so-called laccoliths or cryptodomes, which can cause both explosive eruptions and collapse of the volcanic edifice. Deformation during laccolith emplacement is primarily considered to occur in the host rock. However, shallowly emplaced laccoliths (cryptodomes) show extensive internal deformation. While deformation o...

ملائی, حبیب ,

Mazraeh granidiorite is part of Shyvardag plutonic batholith which is located in eastern Azarbajan, 20 km north of Ahar town and 5 km north of Mazraeh Village. It is a part of Mesozoic –Tertiary igneous belt of the Sanandaj-Sirjan. From petrography and geochemical point of view, rocks are acidic to intermediate and the main part of the body is granodiorite. Texturally, the rock is mainly granul...

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