Abstract Massive sulfide deposits of the Bathurst Mining Camp experienced the following M 1 metamorphic conditions in the Ashgillian to Llandoverian ages (442–430 Ma): Caribou = 350°C, 5.5 kbars; Brunswick 12 = 360°C, 5.8 kbars; Heath Steele and Stratmat = 365°C, 5.5 kbars; and Brunswick 6 = 400°C, 5.8 kbars. Some deposits underwent a Late Silurian or Early Devonian M 2 metamorphism at pressures of ˜3 to 4 kbars and temperatures locally reaching 350° to 400°C. Silicate assemblages within, and in the host rocks of, the deposits exhibit metamorphic conditions identical to those of the sulfide assemblages of the deposits, showing that the deposits were emplaced prior to peak M 1 conditions, compatible with a syngenetic origin. Sphalerite barometry provided accurate, consistent pressure estimates when applied to appropriate assemblages (sphalerite-pyrite- hexagonal pyrrhotite). Arsenopyrite and chlorite-phengite thermometry gave useful temperature estimates. The latter assemblage was calibrated by least squares fitting of 51 pairs of analyses of coexisting chlorite and white mica to a formula deduced from thermodynamic reasoning giving where T e is the temperature of equilibration, and where is the mol fraction of j in the k site. x cl , x am , and x da are the proportions of clinochlore, amesite, and daphnite in chlorite analyses reduced to these three end members plus aluminum-free chlorite. Standard deviation between temperatures estimated from chlorite-phengite thermometry and those estimated by other means is 35°C. The narrow range of P-T observed in the Bathurst camp (350°-400°C, 5.5–5.8 kbars) supports structural observations that some of the nappes containing the California Lake and Tetagouche Groups were assembled and internally deformed prior to the recorded M 1 metamorphism.

Location The Saint John district of southern New Brunswick (Fig. 1), readily reached by major highways, forms an Avalonian terrane of which the essential elements can be examined in one day by means of a road traverse. A street map of the city would be helpful in following the instructions, but the provincial road map should be adequate. Commence at the interchange at Main Street and New Brunswick 1 in downtown Saint John. Procede east on New Brunswick 1 (toward Moncton) for 2.8 mi (4.5 km) to Stop 1, a large quarry on the south side of the highway. Precede another 300 yd (275 m) on New Brunswick 1 to Stop 2. Reverse directions on New Brunswick 1 at the Rothesay interchange, 0.3 mi (0.5 km) farther east, exit from New Brunswick 1 westbound at Thurston Drive (about 0.8 mi [1 km] west of the Rothesay interchange) and follow signs to Cherry Brook Zoo (Stop 3). Proceed southwest on Sandy Point Road 1.1 mi (1.8 km) to the corner of University Avenue (Stop 4). Continue southwest on Sandy Point Road 1.0 mi ( 1.6 km) to Hazen White School, a large yellow brick building on the west side of the road (Stop 5). Continue on Sandy Point Road south to Hawthorn Avenue (0.7 mi; 1.1 km), turn left on Hawthorn Avenue, cross the Crown Street overpass over New Brunswick 1, and follow signs to Rothesay Avenue. Continue on Rothesay Avenue for 2.2 mi (3.5 km) to the intersection with Golden