Why are only some peraluminous granites hot?
An honours project combining an interest in chemistry and rocks to understand why some granites are so hot.
The average heat production of the continental crust is around 1 µW/m3. Hasterok and Webb (2017) estimate the average heat production rates of granites to be around 3.54 µW/m3. Generally, this anomaly is produced by the enrichment of Th and U in these rocks, usually in minerals such as zircon and monazite.
Peraluminous granites are thought to be derived from metasedimentary material which is rich in these accessory minerals. One might therefore expect all peraluminous granites to be anomalously ‘hot’, but they are not. Granites in central Australia, such as the one below, have heat production values up to 3 times higher than average granite.
This study proposes to examine large geochemical and geochronological data sets of peraluminous granites whose probable sources are identified. We propose to examine the links between tectonic setting, heat producing nature of the metasedimentary source and the heat producing nature of the resultant granitoids.
Methods include U-Pb zircon dating and trace element analysis of accessory minerals at Adelaide Microscopy, and significant data compilation and analysis. There will be no fieldwork associated with this project.
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