GEOLOGY OF THE CANDIA QUADRANGLE, SE NEW HAMPSHIRE: NEW FINDINGS

Recent mapping of the Candia New Hampshire 7.5 minute quadrangle, funded by the USGS EDMAP program, shows that subdivision of Massabesic Gneiss Complex migmatites using foliation spacing index (Kerwin, NEGSA 1999, for areas southwest of the Candia quadrangle) is equally applicable here. Type 1 migmatites (continuous biotite foliation with discontinuous felsic lenses) are best represented within a belt that represents the southwestern extension of a transition zone mapped in the Mt. Pawtuckaway quadrangle by Allard (1998). Type 2 migmatites (continuous biotite foliation and continuous felsic layers) is mapped as a lens that closes northeasterly and Type 3 migmatites (continuous felsic layers with discontinuous to swirly biotite foliation) occupies the central region of the MGC with chaotic migmatitic structures. Also noted are granitic sills of unknown age and affinity and extensive granites, of probable Devonian age. The Campbell Hill-Hall Mountain-Nonesuch River Fault zone (CHHMFZ) is interpreted as a bounding fault between the Central Maine Terrane (CMT), and Merrimack Group (MG), (Lyons et al., 1997). However, abundant quartzites and pelitic schists south and east of the CHHMFZ have been identified that are more likely equivalent to units of the CMT (lower Rangeley, Perry Mountain Smalls Falls and Madrid formations) than they are with units of the MG (Berwick Formation) as presently shown on the state map. Between the MGC and the Flint Hill fault, pelitic schists and quartzites, some of which preserve primary structures, also lie within Allards' transition zone. These findings exemplify the importance of the continued mapping effort in New Hamsphire to resolve the boundary conditions between the MGC and adjacent units.