Strain analysis & geochronology of Neoproterozoic rocks, Ghubrah Bowl, Oman

Glacially deposited Neoproterozoic rocks (~700 million years old) crop out in the Sultanate of Oman and provide critical information regarding the Earth’s paleoclimate history. The depositional environment of these ancient sandstones and conglomerates within the Ghubrah Formation of the Jabal Akhdar Mountains has been well-researched, yet these are deformed rocks with a well-developed tectonic fabric that is poorly understood in the research community.

In order to fully understand the paleoclimate inferred from the interpreted depositional setting of the Ghubrah Formation, we must also quantify the amount of deformation that occurred after deposition.  My project is motivated by two primary questions: how much deformation did these glaciogenic rocks experience, and when was the Ghubrah Formation deformed? My research will use two principal approaches to satisfy those questions. I will quantify the amount of deformation experienced by the Ghubrah Formation by conducting a finite strain analysis of the clast assemblage within the glacial diamictite. Additionally, my research will determine when deformation occurred by isotopically dating syn-kinematic sericite using 40Ar-39Ar geochronology. I expect my results to illustrate that mud-stone clasts within the Ghubrah Formation diamictite most accurately record the bulk-rock strain in these heterogenous rocks. I predict that sericite formed during regional deformation that occurred during late Paleozoic Hercynian Orogeny, and that 40Ar-39Ar dating of sericite will record the growth of this mineral during deformation.

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