Insight Into The Silicic Rocks of Northwestern Iceland

• Main Author: Styger, Sheena
• Format: Text
• Language: unknown
• Published: Scholarly Commons 2005
• Subjects: Iceland
• Online Access: https://scholarlycommons.pacific.edu/purcc/2005/events/21

Silicic rock origin in Iceland is linked to a combination of fractional crystallization, crustal remelting, and magma mixing. The relationships between basic and intermediate rocks in northwestern Iceland, specifically in the Tröllafell area, provide evidence for fractional crystallization. Using stratigraphic, petrographic, and geochemical data from samples collected in addition to a fractional crystallization model, magma origin for the rocks collected can be traced back to two different sources. The lower basalt unit, main intermediate unit, and upper basalt unit can all be related by fractional crystallization to the most primitive basalt sampled. Fractional crystallization modeling provides evidence that crustal remelting and magma mixing did not play a significant role in formation of the main intermediate unit. The specific source of magma for the rocks can be attributed to one magma chamber or multiple magma chambers that evolved similarly through fractional crystallization. The chemical differences between Tröllafell and the other intermediate rocks cannot be explained by fractional crystallization. The source for Tröllafell is different than the other rocks in the area. Further investigation of the field area, in addition to the surrounding area, is needed to determine the magmatic origin of Tröllafell.