The Umbrella Hill Formation; A Detrital Zircon Study, Poster 32

As the weight of geoscientific analysis on the Vermont Appalachians greatens, an increasingly intact tectonic model of the region has come to be realized, with U-Pb zircon dating playing a major role. Within the Rowe-Hawley... [ view full abstract ]

As the weight of geoscientific analysis on the Vermont Appalachians greatens, an increasingly intact tectonic model of the region has come to be realized, with U-Pb zircon dating playing a major role. Within the Rowe-Hawley Belt of central Vermont is a major suture formed in the closing of the Early Paleozoic Iapetan Ocean. The Hawley slices within this belt include the Moretown, Cram Hill and Umbrella Hill formations. Recently, the provenances of metasediments within the Moretown and Cram Hill have been determined as Gondwanan. In continuation of this work, the proposed study focuses on the Umbrella Hill Formation, the basal conglomerate of the RHB, and the Shaw Mountain Formation. In execution of this investigation, detrital zircons were used to provide crystallization ages, and then correlated to known magmatic signatures of the constrained source terranes. Through LA-ICP-MS analysis of Umbrella Hill zircon grains and Shaw Mountain formations, a series of age peaks have been determined. The peaks produced for the Umbrella hill are centered around, 460 Ma, 600 Ma, and 1000 Ma, suggesting Shelburne Falls Arc, Peri-Gondwanan, and Peri-Laurentian provenances. A single prominent peak was produced for the Shaw Mountain, centered around 445 Ma and suggesting a Bronson Hill Arc provenance.