Petrogenesis of the Colombian arc volcanoes: a regional study

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Cavell, David Edward ORCID: https://orcid.org/0000-0001-9927-114X (2020). Petrogenesis of the Colombian arc volcanoes: a regional study. University of Birmingham. Ph.D.

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Abstract

The petrogenesis of intermediate silica magmas in continental arc settings remains heavily debated. Contention focuses on the importance of slab components (subducted sediments and altered oceanic crust) compared to processes within the overlying plate to imparting the distinctive geochemical signature of intermediate arc lavas. The Colombian Andes are an understudied region compared to other continental arc settings. The region has several compelling features, including a moderate crustal thickness for continental arcs and geochemically well characterised mid and lower crustal basement. This study utilises high quality geochemistry of major and trace elements and isotopes as petrogenetic tracers of the different components and processes within the Colombian Volcanic Arc, demonstrating that mantle derived melts undergo magma mixing and assimilation processes during ascent through the crust, promoting a diversity of geochemical signatures mainly dependent on pathway through the crust and assimilation of specific crustal components. A developing idea is that crustal thickness may act as a control on some arc parameters, and it is clear that magmatism is strongly controlled by crustal features from previous orogenic events, allowing for primitive compositions to be emplaced in contrast to highly fractionated compositions.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

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