Age, chemistry, and tectonic setting of Miramichi terrane (Early Paleozoic) volcanic rocks, eastern and east-central Maine, USA

Volcanic rocks in the Miramichi inlier Maine occur two areas separated by Bottle Lake plutonic complex: Danforth segment (Stetson Mountain Formation) north of complex and Greenfield to south (Olamon Stream Formation). Both suites are dominantly pyroclastic, with abundant andesite, dacite, rhyolite tuffs subordinate lavas, breccias, agglomerates. Rare basaltic a small area tuffs, agglomerates, lavas restricted segment. U–Pb zircon geochronology dates volcanism at ca. 469 Ma, Floian–Dapingian boundary between Lower Middle Ordovician. Chemical analyses reveal calc-alkaline suite erupted continental volcanic arc, either Meductic or earliest Balmoral phase Popelogan arc activity. The most likely correlative Group west-central New Brunswick. Orogen-parallel lithologic chemical variations from Brunswick east-central may result eruptions different centers. bimodal Poplar Maine–New border is 10–20 myr younger than more an early back-arc basin rifting late-stage event. Coeval Miramichi, Weeksboro–Lunksoos Lake, Munsungun Cambrian–Ordovician inliers not consistent tectonic models involving northwestward migration volcanism. This >150 km span cannot be explained single east-facing subduction zone, suggesting one zone/arc region.