AN IMBRICATE MID CRUSTAL SUTURE ZONE: THE MOJAVE-YAVAPAI PROVINCE BOUNDARY IN GRAND CANYON, ARIZONA
The Mojave and Yavapai provinces in southwestern Laurentia contain evolved and juvenile crust respectively, but the nature of their boundary remains uncertain. This paper analyzes the U-Pb-Hf isotopic composition of zircons from both the oldest plutons and metasedimentary rocks in Grand Canyon. My results show that the Vishnu Schist does not support suturing. Paradoxically, plutons east and west of the Crystal shear zone support suturing based on different U-Pb-Hf isotopic characteristics across the shear zone. I interpret the nature of this boundary to be the existence of an Archean substrate which is sampled by plutons west of the shear zone. The overlapping Vishnu Schist suggests a more complicated architecture. The Vishnu Schist was deposited across Mojave and Yavapai crust, and imbricated during the Yavapai orogeny. The ultimate architecture is a distributed boundary with slivers of plutons carrying the isotopic signature of their respective provinces imbricated within metasediments.
Grand Canyon, Hf isotopes, Mojave province, Yavapai province, Paleoproterozoic
Networked Digital Library of Theses and Dissertations