Garnet zoning: the effect of deformation induced preferential dissolution and redistribution in porphyroblasts during foliation development
Kim, Hyeong Soo (2000) Garnet zoning: the effect of deformation induced preferential dissolution and redistribution in porphyroblasts during foliation development. Geosciences Journal, 4 (Special Edition). pp. 23-28.
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[Extract] Porphyroblast growth is controlled both by deformation and by the chemical reactions that take place during metamorphism(e.g. Karabinos, 1984; Bell et al., 1986; Bell and Hayward 1991; Gibson, 1992; Spear, 1993; Williams, 1994). Bell, et al. (1986) and Bell and Hayward (1991) suggested that dissolution and solution transfer during deformation and metamorphism are controlled by the partitioning of deformation into progressive shearing and progressive shortening components. Williams (1994) suggested a metamorphic/deformation-controlled porphyroblast growth model where growthrate changes were controlled by microstructure development that can be manifested in compositional and textural zoning although the reactions affect the deformation rate. Garnet zoning patterns can be symmetrical or asymmetrical (e.g. Tracy et al., 1976; Hickmott and Spear, 1992). Duebendorfer and Frost (1988) suggested that an original zoning pattern can be modified and truncated by development of schistosity due to selective dissolution during shearing (e.g. Bell, 1985; Bell et al., 1986). Thus asymmetrical or truncated zoning patterns may provide crucial information for interpreting the growth history of porphyroblasts and the mechanism by which they develop in multiply deformed and metamorphosed rocks. This paper presents 2-D and 3-D data and interpretations of the compositional zoning in garnet porphyroblasts that was modified by the concurrent development of surrounding foliations. The development of these foliations caused local preferential dissolution and diffusional effects in zones of progressive shearing affecting the porphyroblast margins.
|Item Type:||Article (Refereed Research - C1)|
|FoR Codes:||04 EARTH SCIENCES > 0403 Geology > 040312 Structural Geology @ 100%|
|SEO Codes:||97 EXPANDING KNOWLEDGE > 970104 Expanding Knowledge in the Earth Sciences @ 100%|
|Deposited On:||07 Jan 2011 10:26|
|Last Modified:||12 Feb 2011 03:55|
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