Ascent rates of the Egersund dikes
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Date
1992-12
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The Ohio State University
Abstract
Continental flood basalts are well studied examples of geologies processes that produce enormous amounts of rock in only a short time. However, the feeder dikes for these CFB's are less well studied in that their ascent rates and flow are unknown. The Egersund dikes of SW Norway are possible CFB feeder dikes associated with the opening of the Iapetus Ocean. For this paper, a program utilizing physical properties and magma composition has calculated ascent rates and volumetric flow for two samples of the Egersund dikes. The data produced by the program indicates ascent rates up to 9 m/sec and volumetric flow of over a kmĀ³ per day. The ascent rates are controlled by viscosity, higher values giving slower flow and vice versa. The viscosity in turn is controlled by magma composition or more specifically the amount of Si02 and Al203. Higher amounts of the framework oxides increase the viscosity and decrease flow velocity. Water content decreases viscosity and incerases flow velocity. Most of the data produced is useless, however, because turbulent flow of the magma makes calculations used unreliable. Further study using calculations compatible with turbulent is needed.