peralkaline

peralkaline

[pər′al·kə‚līn]
(petrology)
Of igneous rock, having a molecular proportion of aluminum lower than that of sodium oxide and potassium oxide combined.
References in periodicals archive ?
Geological mapping and core/channel logging indicate that the host peralkaline rhyolites and trachytes (commendite and pantellerite) to the CREE mineralization at Deep Fox and Foxtrot are the same.
1): Bocabec Gabbro--greyish green, locally layered, medium-grained gabbro and minor associated granitic rocks; Utopia Granite--typically red, leucocratic, medium--to coarse-grained, equigranular, biotite granite; Welsford, Jake Lee Mountain, and Parks Brook granites--beige to pink, mediumgrained and equigranular to fine-grained and porphyritic, amphibole-bearing, peralkaline granites; Magaguadavic Granite--greyish pink, coarse-grained, megacrystic granite; John Lee Brook Granite--light grey, medium-grained, equigranular, garnetiferous, two-mica granite; and Mount Douglas Granite--light pink, medium-to-coarse-grained and equigranular to fine-grained and porphyritic, rapakivitextured, biotite granite.
They also provide a good explanation of where REEs tend to be located, from iron and carbonatite deposits to lateritic, placer, peralkaline, vein, and other deposits.
Based on published data, Jan and Karim (1990) suggested that the alkaline and peralkaline magmatism in the Peshawar plain is related with Permian-Triassic rifting of the Gondwana.
Metaluminous rhyolite obsidian (type S1) from Sacanana (42[degrees]30'S; 68[degrees]36 W) and peralkaline rhyolite obsidian (type T/SC1) from Sierra Negra (42[degrees]18'S; 66[degrees]36'W) have been described for this area (Mendez et al.
REEs can only be found in two types of rocks: carbonatite and peralkaline, one of 17 found in the periodic table.
d) plutonic rocks formed mostly by peralkaline granites, a member of rather sypecial, usually minor bodies forming worldwide occurring post-collisional A-type granitic plutonites (Whalen et al.
None of the samples show a peralkaline character as described for the Arequita Formation by Muzio et al.
The presence of ferrous clinopyroxene cores suggests xenocrysts removed from diferentiated magmas while unusual occurence of acmite in basaltic rocks emphazises their strong peralkaline evolution.
All of the prospects are located within, or proximal to, a Jurassic-aged, multiphase, peralkaline intrusive complex.