Used as Mount Mineral Formation of Proterozoic Z age. Probably correlates with Poplar Mountain Gneiss, but is more aluminous.

Source: GNU records (USGS DDS-6; Reston GNULEX).

Mount Mineral Formation was named by Robinson and others (1973) in the Shutesbury 7.5-min quad, and appears on the State geologic map by Zen (1983). Most of the formation is exposed on Mount Mineral near Shutesbury. Contains aluminous schist, amphibolite, and quartzite; can be differentiated in some areas. Because Mount Mineral Formation probably correlates with Poplar Mountain Gneiss, age is considered to be Late Proterozoic.

Source: GNU records (USGS DDS-6; Reston GNULEX).

Single detrital zircon analyses from the muscovite-garnet bearing upper quartzite member of the Mount Mineral Formation yield ages of 459-439 Ma, indicating that the quartzite is younger than earliest Silurian and may correspond to the Clough Quartzite. Older grains include 1000 Ma, 900 Ma, and 600 Ma groups. Authors state that "drastic rethinking" is required if the rocks of the upper quartzite member of the Mount Mineral, which lie beneath 200 m of Ordovician plutonic rock, are actually Silurian, rather than Proterozoic. The middle mica schist and amphibolite member is shown as Ordovician(?) and the basal quartzite member as Proterozoic(?). The Mount Mineral overlies the Proterozoic Poplar Mountain Gneiss.

Source: GNU records (USGS DDS-6; Reston GNULEX).