REFINED AGES OF PALEOZOIC ROCKS IN RHODE ISLAND AS CONSTRAINTS ON THE FORMATION OF THE APPALACHIAN HOPE VALLEY TERRANE IN SOUTHEASTERN NEW ENGLAND
Here we present revised dates for four key areas of both terranes in southern Rhode Island, namely Ten Rod granite (TRG), Hope Valley alaskite (HVA), Stepping Stone gneiss (SSG) and Scituate granite (SG). Our new preliminary CA-TIMS U-Pb analyses on single zircons allowed us to separate 4 separated magmatic events over the area: ~506 Ma (TRG), ~365 Ma (SSG), ~345 Ma (SG), and ~336 Ma (HVA). These dates are not only significantly more precise than the previously published dates, but also lie entirely outside the time span that the previous dates imply.
Our results document indicate beside a close Avalonian affinity of the Ten Rod granite, a series of closely spaced, short lived intrusive events that contributed to the development of the Hope Valley terrane. Our data also suggest a similarity, on the basis of ages of basement and geochemistry, between the Hope Valley terrane and the Putnam-Nashoba terrane to the north. The present geographical relationship of the Putnam-Nashoba terrane and Bronson Hill anticlinorium suggests that they may be reflective of similar tectonic environments may be parts of the same terrane.