GRANITIC PEGMATITES AS REFLECTIONS OF THEIR SOURCES
| Authors | |
|---|---|
| Year of publication | 2012 |
| Type | Article in Periodical |
| Magazine / Source | Elements |
| MU Faculty or unit | |
| Citation | |
| Doi | http://dx.doi.org/10.2113/gselements.8.4.289 |
| Field | Geology and mineralogy |
| Keywords | pegmatite granite S-type A-type I-type assimilation contamination |
| Description | Pegmatites accentuate the trace-element signatures of their sources, and through that signature pegmatites can commonly be ascribed to origins from granites whose source characteristics are known and distinctive. Interactions with host rocks that might modify the compositions of pegmatites are limited by the rapid cooling and low heat content of pegmatite-forming magmas. Though the plutons from which most pegmatites arise may have extended histories of magma accumulation and contamination by host lithologies, the trace-element signatures of most pegmatites clearly align with those of the S-type (sedimentary source, post-collisional tectonic environment) and A-type granites (anorogenic environment, lower continental crust + mantle source). Pegmatites are not prevalent among the I-type (igneous source) granites, and the distinction between the granites that spawn pegmatites and those that do not appears to stem from the presence or absence, respectively, of fluxing components of B, P, and F at the source. |
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