Date Available
10-10-2017
Year of Publication
2017
Document Type
Master's Thesis
Degree Name
Master of Science (MS)
College
Arts and Sciences
Department/School/Program
Earth and Environmental Sciences (Geology)
Advisor
Dr. Dhananjay Ravat
Abstract
A zone of high magnetization along the SE margin of Paleoproterozoic Laurentia in the United States is indicated by magnetic anomaly data. The SE edge corresponds to the geochemical Neodymium mantle derivation model age (TDM) boundary and the entire anomaly overlies the Paleoproterozoic Mazatzal Province. Two-dimensional gravity and magnetic models across the Nd boundary are created with Moho constrained from receiver functions with gravity, sedimentary thickness and the base of the crustal magnetization. Upper crustal magnetization does not show strong variation across this boundary and much of the strong magnetization appears to lie in the middle crust. Using magnetic modeling of several potential geologic scenarios, we estimate magnetization, depth extent, and width of this zone of high magnetization. The anomaly has variable width (~ 300 km) with amplitude of approximately 200 nT. Pre-1.55Ga Paleoproterozoic mid crustal blocks have significantly higher average effective susceptibility (0.06 SI) than those of the post-1.55Ga Mesoproterozoic (0.01 SI). In two of the three profiles, the Paleoproterozoic zone of high magnetization has the highest average susceptibility indicating the Mazatzal province is innately highly magnetic. The zone may have formed either by magmatism associated with westward subduction or from highly magnetic terranes wedging between accreting island arcs.
Digital Object Identifier (DOI)
https://doi.org/10.13023/ETD.2017.412
Recommended Citation
Durham, Rachel Lauren, "POTENTIAL FIELD MODELING ACROSS THE NEODYMIUM LINE DEFINING THE PALEOPROTEROZOIC-MESOPROTEROZOIC BOUNDARY OF THE SOUTHEASTERN MARGIN OF LAURENTIA" (2017). Theses and Dissertations--Earth and Environmental Sciences. 53.
https://uknowledge.uky.edu/ees_etds/53
