Preliminary geologic map of the Blandford Quadrangle, Hampden ad Hampshire counties, Massachusetts

The bedrock geology of Massachusetts

“…F 4 folds from the northern part of the Rowe-Hawley zone and Connecticut Valley belt have steeply dipping north-trending axial surfaces and subhorizontal or gently northplunging hinges; they are locally associated with a well-developed axial plane slip cleavage ( fig. 9; Hatch and others, 1967;Osberg and others, 1971;Hatch, 1969Hatch, , 1975Hatch and Warren, 1981).…”

“…Available data are insufficient to determine whether this quartzite exposure is part of a feather edge or tiny remnant of the Silurian Russell Mountain Formation or Clough Quartzite or is simply a local and unique lens of very sandy material in the base of the overlying Lower Devonian Goshen Formation. No other exposures of comparable rocks have been reported in any of the previous studies of the Shelburne Falls dome (Balk, 1946;Segerstrom, 1956b;Hatch and Hartshorn, 1968;Leo M. Hall, written commun., 1977;Hatch, 1981). Furthermore, no comparable rocks have been reported from the margins of either the Goshen (Hatch and Warren, 1982) or Woronoco domes.…”

“…A, this volume) and is everywhere overlain by rocks of the Goshen Formation. Hatch (1981) described an "exposure of biotitic quartzite too small to be shown on this map at the contact between the amphibolites of the [pre-Silurian] dome sequence and the Goshen schists 160 m S. 35° E. of the summit of Goodnow Hill" on the southwest flank of the southeast lobe of the Shelburne Falls dome (figs. 3, 4), about 2 km north of Moonstone Hill (see State map).…”

“…Member Dgl, which appears to occupy a stratigraphic interval around the Shelburne Falls dome either at the upper part of member Dg or possibly equivalent to the interval occupied by member Dgq to the south, clearly pinches out near the Vermont State line and south of Ashfield ( fig. 3) (Hatch, 1981). Member Dgc, which forms the base of the Goshen around the Woronoco dome, is not present around the Goshen dome to the north, or at the base of the Goshen to the west, and thus must pinch out or undergo a facies change both north and west of the Woronoco dome.…”

“…In this area, F 4 is thought to be responsible for deflections of S 3 cleavage on a map scale (Hatch, 1981;Hatch and Warren, 1981) and for folds in beds and in S2 schistosity, but only rarely can it be demonstrated to deform S 3 structures in outcrop (see, for example, Osberg and others, 1971, fig. 2).…”