RT Journal Article
SR Electronic
T1 The petrogenesis of the Highlandcroft and Oliverian Plutonic Suites, New Hampshire: Implications for the structure of the Bronson Hill terrane
JF American Journal of Science
JO Am J Sci
FD American Journal of Science
SP 73
OP 99
DO 10.2475/01.2008.03
VO 308
IS 1
A1 Michael J. Dorais
A1 Jenny Workman
A1 Jugdeep Aggarwal
YR 2008
UL http://www.ajsonline.org/content/308/1/73.abstract
AB Both Laurentian and peri-Gondwanan origins for the Oliverian and Highlandcroft Plutonic Suites of New Hampshire have been proposed. A peri-Gondwanan origin places the Red Indian Line, the principle Iapetus suture, to the west of the Bronson Hill Anticlinorium and requires the plutons to be allochthonous. In contrast, a Laurentian margin emplacement setting places the Red Indian Line farther to the east in New Hampshire. The combination of εNd and 207Pb/204Pb values are most compatible with the suites representing mixtures of arc-derived magmas and Laurentian crust, indicating that both suites were derived to the west of the Red Indian Line. The tectonic setting for the arc probably was a westerly dipping subduction zone under the Laurentian margin, resulting from a polarity flip after the collision of the Shelburne Falls arc during the Taconic orogeny. Bulk-rock major and trace elements, as well as Nd, Sr, and Pb isotopic results, indicate that the Highlandcroft and Oliverian Plutonic Suites of New Hampshire are both members of the same arc complex.