Outgassing and eruption of basaltic magmas: The effect of conduit geometry

Geology ◽  
2017 ◽  
pp. G38787.1 ◽  
Author(s):  
L. Pioli ◽  
B.J. Azzopardi ◽  
C. Bonadonna ◽  
M. Brunet ◽  
A.K. Kurokawa
Keyword(s):  
Basaltic Magmas

Re-Os isotope characteristics of postorogenic lavas: Implications for the nature of young lithospheric mantle and its contribution to basaltic magmas

Geology ◽  
2000 ◽  
Vol 28 (6) ◽  
pp. 563-566 ◽  
Author(s):  
Bruce F. Schaefer ◽  
Simon P. Turner ◽  
Nick W. Rogers ◽  
Chris J. Hawkesworth ◽  
Helen M. Williams ◽  
...  
Keyword(s):  
Lithospheric Mantle ◽  
Basaltic Magmas ◽  
Os Isotope

Anorthite megacrysts from island arc basalts

1995 ◽  
Vol 59 (394) ◽  
pp. 1-14 ◽  
Author(s):  
Mitsuyoshi Kimata ◽  
Norimasa Nishida ◽  
Masahiro Shimizu ◽  
Shizuo Saito ◽  
Tomoaki Matsui ◽  
...  
Keyword(s):  
Planetary Nebula ◽  
Isotope Ratio ◽  
Island Arc ◽  
Japanese Island ◽  
Sr Isotope ◽  
Native Copper ◽  
Chemical Zoning ◽  
Basaltic Magmas ◽  
End Members ◽  
Lateral Variations

AbstractAnorthite megacrysts are common in basalts from the Japanese Island Arc, and signally rare in other global fields. These anorthites are 1 to 3 cm in size and often contain several corroded Mg-olivine inclusions. The megacrysts generally range from An94Ab4Ot2 to An89Ab6Ot5 (Ot: other minor end-members, including CaFeSi3O8, CaMgSi3O8, AlAl3SiO8, □Si4O8) and show no chemical zoning. They often show parting. Redclouded megacrysts contain microcrystals of native copper with a distribution reminiscent of the shape of a planetary nebula. Hydrocarbons are also present, both in the anorthite megacrysts and in the olivines included within them. Implications of lateral variations in the Fe/Mg ratio of the included olivines, in Sr-content and in Sr-isotope ratio of the anorthite megacrysts with respect to the Japanese island arc, relate to mixing of crustal components and subducted slab-sediments into the basaltic magmas.

scholarly journals Equilibrium, Disequilibrium, and Crystal Growth in Basaltic Magmas

2020 ◽  
Author(s):  
Margaret E. Hartley ◽  
Fabio Arzilli ◽  
Margherita Polacci ◽  
Giuseppe La Spina ◽  
Mike R. Burton ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Basaltic Magmas

Origin and evolution of Neogene alkali-basaltic magmas in the southwestern flank of the Baikal rift system (Heven lava plateau, northern Mongolia)

2014 ◽  
Vol 55 (2) ◽  
pp. 190-215 ◽  
Author(s):  
S.S. Tsypukova ◽  
A.B. Perepelov ◽  
E.I. Demonterova ◽  
L.A. Pavlova ◽  
A.V. Travin ◽  
...  
Keyword(s):  
Rift System ◽  
Origin And Evolution ◽  
Baikal Rift System ◽  
Northern Mongolia ◽  
Basaltic Magmas

scholarly journals What lies beneath? Reconstructing the primitive magmas fueling voluminous silicic volcanism using olivine-hosted melt inclusions

Geology ◽  
2020 ◽  
Vol 48 (5) ◽  
pp. 504-508 ◽  
Author(s):  
Simon J. Barker ◽  
Michael C. Rowe ◽  
Colin J.N. Wilson ◽  
John A. Gamble ◽  
Shane M. Rooyakkers ◽  
...  
Keyword(s):  
Melt Inclusions ◽  
Melt Inclusion ◽  
Taupo Volcanic Zone ◽  
Mantle Dynamics ◽  
Silicic Volcanism ◽  
Depleted Mantle ◽  
Basaltic Magmas ◽  
Show Evidence ◽  
Basaltic Melts ◽  
Eruptive Centers

Abstract Understanding the origins of the mantle melts that drive voluminous silicic volcanism is challenging because primitive magmas are generally trapped at depth. The central Taupō Volcanic Zone (TVZ; New Zealand) hosts an extraordinarily productive region of rhyolitic caldera volcanism. Accompanying and interspersed with the rhyolitic products, there are traces of basalt to andesite preserved as enclaves or pyroclasts in caldera eruption products and occurring as small monogenetic eruptive centers between calderas. These mafic materials contain MgO-rich olivines (Fo79–86) that host melt inclusions capturing the most primitive basaltic melts fueling the central TVZ. Olivine-hosted melt inclusion compositions associated with the caldera volcanoes (intracaldera samples) contrast with those from the nearby, mafic intercaldera monogenetic centers. Intracaldera melt inclusions from the modern caldera volcanoes of Taupō and Okataina have lower abundances of incompatible elements, reflecting distinct mantle melts. There is a direct link showing that caldera-related silicic volcanism is fueled by basaltic magmas that have resulted from higher degrees of partial melting of a more depleted mantle source, along with distinct subduction signatures. The locations and vigor of Taupō and Okataina are fundamentally related to the degree of melting and flux of basalt from the mantle, and intercaldera mafic eruptive products are thus not representative of the feeder magmas for the caldera volcanoes. Inherited olivines and their melt inclusions provide a unique “window” into the mantle dynamics that drive the active TVZ silicic magmatic systems and may present a useful approach at other volcanoes that show evidence for mafic recharge.

scholarly journals The system CaO-MgO-FeO-SiO2 and its bearing on the origin of ultrabasic and basic rocks

1960 ◽  
Vol 32 (249) ◽  
pp. 459-470 ◽  
Author(s):  
Peter J. Wyllie
Keyword(s):  
Experimental Data ◽  
Temperature Interval ◽  
Wide Temperature Range ◽  
Multicomponent System ◽  
Small Temperature ◽  
Experimental Procedure ◽  
Temperature Range ◽  
A Value ◽  
Basaltic Magmas ◽  
Basic Rocks

SummaryExperimental data in the system CaO-MgO-FeO-SiO2 suggest that there may be a plateau on the liquidus and solidus of the multicomponent system basalt-peridotite. If this is so, fusion of peridotite would produce only basaltie magmas over a wide temperature range; when the temperature reached a value such that the liquid crossed the threshold of the plateau, there would be a rapid increase in the amount of fusion for small temperature increases, with the formation of picritic magmas; basaltic magmas containing suspended forsteritic olivine crystals could dissolve them if the temperature rose slightly above that of the plateau threshold; a high proportion of a picritic magma would crystallize in a small temperature interval, with the precipitation of forsteritic olivine that was only slightly zoned. These possibilities are compared with current theories, and it is concluded that several petrological axioms may require critical re-examination. An experimental procedure is outlined to determine the shape of the liquidus and solidus in the basalt-peridotite system.

Trends of differentiation in basaltic magmas

1933 ◽  
Vol s5-25 (147) ◽  
pp. 239-256 ◽  
Author(s):  
W. Q. Kennedy
Keyword(s):  
Basaltic Magmas

Olivine, pyroxene, feldspar, and spinel in ultramafic nodules from Auckland, New Zealand

1969 ◽  
Vol 37 (287) ◽  
pp. 375-390 ◽  
Author(s):  
K. A. Rodgers ◽  
R. N. Brothers
Keyword(s):  
High Temperature ◽  
New Zealand ◽  
Composition Range ◽  
Lattice Structure ◽  
Element Distribution ◽  
Uppermost Mantle ◽  
X Ray ◽  
Basaltic Magmas ◽  
Primary Crystals ◽  
Large Primary

SummaryChemical, optical, and X-ray data are presented for forsteritic olivine, bronzite-enstatite, diopsidic augite, anorthite, and spinel from ultramafic nodules at seven localities in Auckland province. Olivine has a composition range from Fo79–93 for large primary crystals to Fo80–100 for smaller interstitial grains. Orthopyroxenes (En83–96) carry exsolution lamellae of clinopyroxene parallel to (100); clinopyroxenes are mainly diopsidic augites with exsolved bronzite. The plagioclase (An97) has high-temperature characteristics and a lattice structure probably transitional between primitive and body-centred anorthite. Spinels include chromite, picotite, ceylonite, hercynite, and magnetite. Element distribution indicates that the ultramafic assemblages attained equilibrium at temperatures near 1250 °C and at moderate pressures, corresponding to the melting interval of anhydrous basaltic magmas within the uppermost mantle.

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