Generation of sodium-rich magmas from newly underplated basaltic crust

  title={Generation of sodium-rich magmas from newly underplated basaltic crust},
  author={Michael P. Atherton and Nick Petford},
SODIUM-RICH rocks of trondhjemite–tonalite–dacite (TTD) or –granodiorite (TTG) suites form much of Precambrian continental crust1. They are thought to have formed by partial melting of subducted oceanic crust2,3—a process that would have been much more widespread early in Earth history than at present, owing to the higher thermal gradients prevailing at that time4. Phanerozoic TTD suites do exist, however, and seem also to relate to subduction zones5. Defant and Drummond6 proposed that these… 
Petrogenesis of slab-derived trondhjemite–tonalite-dacite/adakite magmas
The prospect of partial melting of the subducted oceanic crust to produce arc magmatism has been debated for over 30 years. Debate has centred on the physical conditions of slab melting and the lack
Evidence for mantle metasomatism by hydrous silicic melts derived from subducted oceanic crust
It is shown that the melting of basalt under both H2O-added and low-temperature conditions can yield extremely alkali-rich silicic liquids, the alkali content of which increases with pressure, suggesting that mantle metasomatism by slab-derived melt is a more common process than previously thought.
The Cretaceous Separation Point batholith, New Zealand: granitoid magmas formed by melting of mafic lithosphere
The Early Cretaceous Separation Point batholith of the South Island, New Zealand, represents the final magmatic stage of an extensive arc system located on the SW Pacific margin of Gondwana during
Lithospheric Removal as a Trigger for Flood Basalt Magmatism in the Trans-Mexican Volcanic Belt
The voluminous succession of tholeiitic basalts, calc-alkaline andesites and minor high-K basalts that form the Late Miocene Altos de Jalisco mafic province of the western Trans-Mexican Volcanic Belt
Trace element geochemistry of orogenic igneous rocks and crustal growth models
Some of the more important constraints on crustal growth mechanisms are reviewed in relation to the trace element composition of orogenic igneous rocks, with specific reference to granitoids, and in


Effect of steeper Archean geothermal gradient on geochemistry of subduction-zone magmas
The comparative study of Archean and post-Archean granitic rocks shows significant changes with time. The high rare-earth element fractionation and the low Yb content of the Archean granitoids
Derivation of some modern arc magmas by melting of young subducted lithosphere
MOST volcanic rocks in modern island and continental arcs are probably derived from melting of the mantle wedge, induced by hydrous fluids released during dehydration reactions in the subducted
A model for Trondhjemite‐Tonalite‐Dacite Genesis and crustal growth via slab melting: Archean to modern comparisons
The petrogenesis of trondhjemite-tonalite-dacite (TTD) involves all major petrologic models in various tectonic settings. A specific subtype of TTD, high-Al type, is the one most commonly associated
Density constraints on the formation of the continental Moho and crust
The densities of mantle magmas such as MORB-like tholeiites, picrites, and komatiites at 10 kilobars are greater than densities for diorites, quartz diorites, granodiorites, and granites which
Isotope and Trace Element Data for Orogenic Andesites from the Austral Andes
The Austral Volcanic Zone of the Andes (AVZ, 49–55°S) consists of six Pleistocene to Recent volcanic centres resulting from the subduction of the Antarctic plate beneath southernmost South America.
Geochemical characteristics of central Chile (33 °–34 °S) granitoids
Seventeen granitoid samples from batholiths in central Chile (33 °–34 ° S) have been analyzed for trace element content. The samples range in age from Paleozoic to Tertiary, and in rock type from
Generation of trondhjemitic-tonalitic liquids and Archean bimodal trondhjemite-basalt suites
Trondhjemitic and tonalitic liquids may form either by igneous differentiation of less silicic, more mafic liquids or by partial melting of rocks of basaltic composition. Low-Al 2 O 3