PT  - JOURNAL ARTICLE
AU  - Michael J. Dorais
AU  - Jenny Workman
AU  - Jugdeep Aggarwal
TI  - The petrogenesis of the Highlandcroft and Oliverian Plutonic Suites, New Hampshire: Implications for the structure of the Bronson Hill terrane
AID  - 10.2475/01.2008.03
DP  - 2008 Jan 01
TA  - American Journal of Science
PG  - 73--99
VI  - 308
IP  - 1
4099  - http://www.ajsonline.org/content/308/1/73.short
4100  - http://www.ajsonline.org/content/308/1/73.full
SO  - Am J Sci2008 Jan 01; 308
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.