Date of Award

Spring 5-22-2021

Degree Type


Degree Name

Doctor of Philosophy (PhD)


Earth Sciences


Scott D. Samson


Grenville, Hf, O, Ti-in-zircon, U-Pb, Zircon

Subject Categories

Earth Sciences | Geochemistry | Geology | Physical Sciences and Mathematics


The Mesoproterozoic (1.4-0.9 Ga) Grenville Orogeny led to the formation of the supercontinent Rodinia. One unique characteristic of the Grenville Orogeny is that it produced a volumetrically significant amount of zirconium- (Zr) enriched granitoids, evidently more than any period both prior to and after the Grenville. To investigate this further, Mesoproterozoic basement rocks were sampled along the axis of the current Appalachian Mountains from western North Carolina north to southern New York, as well as from the northern Andes in southern Colombia. Zircon was extracted from these rocks to exploit its propensity to incorporate several isotopic tracers useful in determining age, petrogenesis, and thermal conditions during crystallization. These include Uranium-Lead (U-Pb), Hafnium (Hf), the rare earth elements (REE), stable isotopes of Oxygen (O), and Titanium (Ti). Using these isotope systems together, the main goal of the research presented here is to better our understanding of the tectonic history of southeastern Laurentia during the Mesoproterozoic (Chapter 1), to investigate the potential link between Laurentia and Amazonia during the formation of Rodinia (Chapter 2), and to elucidate the tectonic processes responsible for creating Zr-enriched magmas (Chapter 3).


Open Access