Campus Only Senior Thesis
Bachelor of Arts
Jade Star Lackey
© 2016 Zoe Y. G. Dilles
The Ruby-Humboldt Range in Northeastern Nevada exposes the deepest crust in the western portion of the Sevier Hinterland. The product of unique brittle and ductile accommodations, this block of lower crustal rock is a window into the processes of continental thickening and extension. The structure of the northern tip of the Ruby-Humboldt Range core complex is dominated by a large recumbent fold nappe with a southward closeure cored by Paleoproterozoic-Archean gneissic complexes with complex interdigitated field relationships that record polyphase continental metamorphism. Amphibolite-grade metapelitic rocks within the core and Winchell Lake nappe record a wide range of zircon age dates of metamorphic events the oldest of which at ~2.5 Ga is recorded in adjacent orthogneiss as a crystallization age. At least two younger metamorphic events are recorded within this orthogneiss, most significantly at 1.7-1.8 Ga, an event previously unpublished for this region that links it to Wyoming province activity in addition to inherited component of detrital cores up to 3.7 Ga in age that is among the oldest ages reported in Nevada. The youngest overprint of cretaceous metamorphic overgrowth ranges fro 60-90 Ma in age based on zircon rims in the aforementioned units as well as three garnet amphibolites that intrude the core of the nappe and are interpreted to be metabasic bodies.
Dilles, Zoe Y G, "Geochronologic and Petrologic Context for Deep Crustal Metamorphic Core Complex Development, East Humboldt Range, Nevada" (2016). Scripps Senior Theses. 811.
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