scholarly journals Peralkaline silicic extrusive rocks: magma genesis, evolution, plumbing systems and eruption

2021 ◽  
Vol 353 (S2) ◽  
pp. 1-53
Author(s):  
Ray Macdonald ◽  
John C. White ◽  
Harvey E. Belkin
Keyword(s):  
Magma Genesis ◽  
Plumbing Systems

BASALTIC MAGMA GENESIS AND MANTLE SOURCES BENEATH TWO CENOZOIC VOLCANOES, MT. EARLY AND SHERIDAN BLUFF, EAST ANTARCTICA

2020 ◽  
Author(s):  
Yuyu Li ◽  
◽  
K.S. Panter ◽  
John L. Smellie ◽  
Jerzy S. Blusztajn ◽  
...  
Keyword(s):  
Basaltic Magma ◽  
East Antarctica ◽  
Magma Genesis ◽  
Mantle Sources

scholarly journals Sunda arc mantle source δ18O value revealed by intracrystal isotope analysis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Frances M. Deegan ◽  
Martin J. Whitehouse ◽  
Valentin R. Troll ◽  
Harri Geiger ◽  
Heejin Jeon ◽  
...  
Keyword(s):  
Mantle Source ◽  
Secondary Ion Mass Spectrometry ◽  
Isotope Composition ◽  
Isotope Analysis ◽  
Sunda Arc ◽  
Mid Ocean Ridge ◽  
Plumbing Systems ◽  
Ocean Ridge ◽  
Secondary Ion ◽  
Magma Plumbing

AbstractMagma plumbing systems underlying subduction zone volcanoes extend from the mantle through the overlying crust and facilitate protracted fractional crystallisation, assimilation, and mixing, which frequently obscures a clear view of mantle source compositions. In order to see through this crustal noise, we present intracrystal Secondary Ion Mass Spectrometry (SIMS) δ18O values in clinopyroxene from Merapi, Kelut, Batur, and Agung volcanoes in the Sunda arc, Indonesia, under which the thickness of the crust decreases from ca. 30 km at Merapi to ≤20 km at Agung. Here we show that mean clinopyroxene δ18O values decrease concomitantly with crustal thickness and that lavas from Agung possess mantle-like He-Sr-Nd-Pb isotope ratios and clinopyroxene mean equilibrium melt δ18O values of 5.7 ‰ (±0.2 1 SD) indistinguishable from the δ18O range for Mid Ocean Ridge Basalt (MORB). The oxygen isotope composition of the mantle underlying the East Sunda Arc is therefore largely unaffected by subduction-driven metasomatism and may thus represent a sediment-poor arc end-member.

Magma genesis in an ongoing rifting zone: The Tadjoura Gulf (Afar area)

1993 ◽  
Vol 57 (10) ◽  
pp. 2291-2302 ◽  
Author(s):  
J.A Barrat ◽  
B.M Jahn ◽  
S Fourcade ◽  
J.L Joron
Keyword(s):  
Magma Genesis
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