The amphiboles of the REE-rich A-type peralkaline Strange Lake pluton – fingerprints of magma evolution

Abstract

(2017) The amphiboles of the REE-rich A-type peralkaline Strange Lake plutonfingerprints of magma evolution. Lithos 288:156-174.

Alkali pyroxenes and amphiboles: a window on rare earth elements and other high field strength elements behavior through the magmatic-hydrothermal transition of peralkaline granitic systems

“…The Strange Lake complex consists of a hypersolvus granite, while a younger, largely metasomatized transsolvus granite (rare perthite plus two distinct feldspars, previously classified as subsolvus, e.g. Boily and Williams Jones, 1994) surrounds it, forming the majority of the complex (Gysi et al 2016;Siegel et al 2017b). These plutons are partially bounded by an outwardly-dipping fracture associated with fluorite and hematite breccia.…”

“…This last substitution increases the size of the C site, leaving more space to incorporate LREE. Similarly, the coupled substitution (Mg, Fe 2+ )  Fe 3+ occurring in the C site of amphiboles enhances HREE incorporation (Bottazzi et al 1999;Siegel et al 2017b). Amphibole chondrite-normalized REE patterns are systematically enriched in HREE relative to LREE, with a depression in medium REE (MREE, from…”

“…Their variation in trace element composition is directly linked to the environment they grew in, a highly evolved melt, enriched in incompatible elements. Among incompatible elements are the REE, which are known to be preferentially incorporated in alkaline amphiboles along with Na for LREE and Fe 3+ for HREE (Bottazzi et al 1999;Siegel et al 2017b). Due to this crystallo-chemical control, amphiboles can incorporate a lot of REE at the magmatic stage, with a preference for HREE.…”

Compositional Variation of Amphiboles During Magma Mixing: A Case Study of Huangyangshan A-Type Granite in Kalamaili Metallogenic Belt, East Junggar, China

“…This complexity gives rise to a complicated classification for amphiboles (Hawthorne et al, 2012). Owing to the complexity, amphiboles are capable of accommodating a variety of elements with variable ionic charges and radii, including alkali elements, rare earth elements (REE), high field strength elements (HFSE), and large ion lithophile elements (LILE) (Siegel et al, 2017). Therefore, amphiboles are sensitive to chemical compositions of the crystallizing melts and may record some processes during magma evolution.…”

An Isotope Study of the Dzhida Mo–W Ore Field (Western Transbaikalia, Russia)

“…Researchers consider that mineralization could be formed by several mechanisms. In one case, it occurs due to the intensive differentiation of a standard granite melt [11][12][13], while in another case it is expected to occur due to the transport of elements to the apical part of a magmatic chamber [14], or as a result of special melting conditions and the involvement of special sources of fluids [15,16]. Some researchers have proposed that metasomatic processes caused a redistribution of rare metals [17,18].…”