adakites

adakites

[′a·də‚kīts]
(geology)
Rocks formed from lavas that melted from subducting slabs associated with either volcanic arcs or arc/continent collision zones; they were first described from Adak Island in the Aleutians.
References in periodicals archive ?
10a), and higher K (~3.6 wt%), Ba (~712 ppm) and Rb (~86 ppm) contents than that of adakites. The samples have also high Sr contents and are found on the TTG area, rather than on the arc one in Fig.
12a, b, samples fall mostly in the field of adakites derived from the partial melting of the thick lower crust and metabasaltic and eclogite fields, rather than in that of adakite rocks derived from the partial melting of the delaminated lower crust.
Detailed studies have shown that the rocks are high-Si[O.sub.2] adakites (HSA) and that the parental magma was generated as a result of subduction and partial melting of an oceanic slab and its overlying sediments and have a post-collisional affinity (Kohnavard, 2015).
The samples mostly show affinity to plot near the Ghoshchi alkali gabbros (unpublished data), Suffi-abad I-type granites [21], and Eastern Pontides adakites [22] (Figure 7).
adakites, shoshonites, and boninites) are reviewed and the paper concludes with a brief overview of arc rocks in ancient settings.
Shoshonites, boninites and adakites are volumetrically small, but are nonetheless petrologically significant igneous rocks that form in specialized arc environments.
Hood andesites suggest magma formation by partial melting of subducted oceanic lithosphere (adakites), rather than by partial melting of ultramafic rock within the sub-volcanic arc mantle wedge.
Variable enrichment of Ba relative to Rb and Th of the type displayed by the Ross Island Formation andesite samples is also observed in adakites from the Austral Volcanic Zone of the Andes (Stern and Kilian 1996; Wilson 1989).