Oceanic island-arc

Many granitic plutonic rocks throughout the world have relatively uniform 0-contents with 5 0-values between 6 and 10%c. Granitoids at the low 0 end of the normal group have been described from oceanic island - arc areas where continental crust is absent (e.g., Chivas et al. 1982). Such plutons are considered to be entirely mantle-derived. Granites at the high end of the normal 0-group may have... 

Altogether, tectonically emplaced and abyssal mantle rocks provide insights into upper mantle compositions and processes that are complementary to the information conveyed by mantle xenoliths (See Chapter 2.05). They provide coverage to vast regions of the Earth s upper mantle that are sparsely sampled by mantle xenoliths, particularly in the ocean basins and beneath passive continental margins, back-arc basins, and oceanic island arcs. 

Except for active rifts and some intra-oceanic island arcs, which exhibit the highest middle-cmst P-wave velocities (6.7 0.3 km s (Rudnick and Fountain, 1995) and... 

Suyehiro K., Takahaski N., Ariie Y., Yokoi Y., Hino R., et al. (1996) Continental crust, crustal underplating, and low-Q upper mantle beneath an oceanic island arc. Science 272, 390-392. 

Sun, S.S., 1980. Lead isotopic study of young volcanic rocks from mid-ocean ridges, ocean islands arcs. Philosophical Transactions of the Royal Society of London, 297 409-445. 

Figure SJ4 The La/Yb-Sc/Ni discriminadon diagram for andesites (after Bailey, 1981) showing the fields of Andean-type (active continental margin), continental island-arc, low-K oceanic island-arc and other oceanic island-arc andesites.

Oceanic island-arc — fore-arc or back-arc basins, adjacent to a volcanic-arc developed on oceanic or thin continental crust. 

The fields arc oceanic island-arc, continental island-arc, active continental margin and passive margin., ... 

Spider diagrams Shale-normalized spider diagrams were shown to be distinctive for shales deposited oj discriminants in oceanic island-arcs, passive continental margins and destructive margins... 

The Bowers Terrane is located east of the Wilson Terrane and is separated from it by the Lanterman fault zone which has been traced from the Bowers Mountains on the Oates Coast to the Lady Newness Bay on the Borchgrevink Coast of the Ross Sea. The Bowers Terrane appears to be a sliver of a much larger land-mass that originally included an oceanic island-arc system. It is composed of oceanic tholeiites interbed-ded with and overlain by fossiliferous sedimentary rocks that were deposited in a marine environment. The rocks were compressed by westward-directed forces that caused the rocks to be folded and faulted. However, the metamorphic grade is lowermost green-schist facies. The eastern boundary of the Bowers... 

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