wiborgite

wiborgite

[′wī‚bȯr‚gīt]
(petrology)
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References in periodicals archive ?
Hornblende-plagioclase thermometry and aluminiumin-hornblende barometry within wiborgite record crystallization temperatures between 670 and 800 [degrees]C, at pressures of 2.5-5.4 kbar (Elliott 2001).
The analysed quartz crystallization temperatures from the Suursaari quartz porphyry are close to the lower values of wiborgite crystallization temperatures from the Wiborg and Salmi plutons (Shebanov et al.
The analysed quartz crystallization temperatures are close to lower values of wiborgite crystallization temperatures from the Wiborg (670-890 [degrees]C) and Salmi (680-780 [degrees]C) rapakivi batholiths.
The granitic rocks forming the central part of the Riga massif are mostly pink, massive, coarse-grained biotite-hornblende rapakivi granites, petrographically identical to the wiborgite and pyterlite of the Wiborg batholith (see Ramo & Haapala 1995).
1) consists of five granite types: wiborgite, pyterlite, even-grained granite, porphyry aplite, and porphyritic granite, of which wiborgite is the most common granite type (see also Simonen 1987) (Fig.
rapakivi weathering affects mostly coarse-grained rapakivi granite types, in particular wiborgite. Dark varieties of rapakivi with a higher content of amphibole and mica have a higher tendency to weather than light varieties.
The Wiborg rapakivi granite batholith consists of five granite types: wiborgite, pyterlite, even-grained granite, porphyritic granite, and porphyry aplite (Fig.
Wiborgite ("normal rapakivi") is the main rapakivi granite type in the Wiborg batholith.
The colour of wiborgite varies, sometimes on one and same outcrop.
The macroscopic fracture pattern in wiborgite is orthogonal, with fractures both open and closed (Fig.
In places, wiborgite is weathered on a single outcrop with nearly intact and weathered parts mixed randomly together.
Transition of pyterlite to wiborgite and to porphyritic rapakivi granite is observed.