Title

The A-type Mount Scott Granite Sheet: Importance of Crustal Magma Traps

Abstract

The presence of rapakivi feldspar and of distinctive porphyritic texture of Mount Scott Granite indicates a period of crystallization prior to final emplacement beneath an extensive penecontemporaneous rhyolite volcanic pile provides pressure estimates which are interpreted as plumbing the depth of a temporary storage chamber at ~ 7-8 km. Based on magmastatic calculations, it is suggested that horizontal anisotropies become crustal magma traps where the magma driving pressure exceeds the lithostatic load when the anisotropy is encountered. During rifting, initial large influxes of magma may proceed passed crustal anisotropies but have the effect of increasing the relative magma driving pressure through reducing horizontal stress. Thus, magma driving pressure may eventually exceed the lithostatic load at the depth of the brittle-ductile transition thereby activating this crustal magma trap.

Department(s)

Geosciences and Geological and Petroleum Engineering

Keywords and Phrases

Brittle/ductile Transition; Granite; Magma Ascent; Magma Trap; Petrogenesis

International Standard Serial Number (ISSN)

1480227

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 1995 Wiley-Blackwell, All rights reserved.

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