The Munsungun area of northern Maine is an early Paleozoic terrane within the Central Mobile Belt (CMB) of the northern Appalachians. The Bluffer Pond Formation of the Munsungun Terrane is composed primarily of pillow basalt and gabbro with minor intercalated sediments and has a maximum thickness of 1230 m. This unit is of early-Late Ordovician (Caradocian) age, based on paleontological data, and folding most likely occurred during the Devonian (Acadian Orogeny). This region has been metamorphosed to subgreenschist facies. Samples for paleomagnetic study have been obtained from 15 sites of pillow basalt and seven sites of gabbro within the Bluffer Pond Formation. Natural remanent magnetization (NRM) directions are similar to the expected present-day field direction and are interpreted to be strongly affected by a viscous overprint. Detailed stepwise thermal demagnetization fails to adequately resolve a partial overprint direction with intermediate blocking temperature, but stable endpoints combined with great circles do isolate a characteristic high-temperature component carried by magnetite as indicated by unblocking temperatures and rock magnetic experiments.

After tilt correction the formation mean calculated from pillow basalt sites only is D=339¿, I=-33¿ (k=12, α95=14¿, n=11), with a corresponding paleopole of 23¿N, 133¿E (Δp=9¿, Δm=16¿), calculated for an average site location of 46.5¿N, 291¿E. When both pillow basalt and gabbro sites are used to calculate a tilt-corrected formation mean, the result is D=339¿, I=-28¿ (k=12, α95=12¿, n=24), and this characteristic component passes a tectonic tilt test. The calculated paleopole (26¿N, 134¿E; Δp=7¿, Δm=13¿) from pillows and gabbros falls near (but not on) the Ordovician apparent polar wander path segment for North America and yields a paleolatitude (18¿¿9¿S) similar to that of the Lunksoos Terrane which is located farther to the southeast within the CMB of Maine. The Laurentian margin at this time was located at paleolatitudes of 15--20¿S. The paleogeographic implication of this result is that the Munsungun Terrane was located near the Laurentian margin within the Iapetus Ocean and this near-continent location is consistent with a marginal or back arc basin tectonic environment for the extrusion of the Bluffer Pond volcanics. ¿ American Geophysical Union 1993