sgr ms thesis - University of Maine

Biotite is metamorphic in origin, and some grains show replacement by chlorite.
Pyrite and magnetite are also common and are assumed to be authogenic.
Metzger (1959) determined three different sediment sources that
produced the observed stratified rock types within the Bar Harbor Formation. The
vast majority of sediments came from Ellsworth Schist and amphibolite units that
lie just below the Bar Harbor Formation. Detrital quartzite and microcline could
only have come from the Ellsworth Schist as it is the only facies in which both
exist in abundance. Where present, microcline is often heavily altered to sericite.
Volcanic tuff layers were produced by the volcanic activity along the convergent
boundary. The volcanic lithic shards are heavily altered and rounded, implying
that they are more mature sediments from a distant source. Biotite and chlorite
are an authigenic result of weak metamorphism. Beds are often well sorted and
display micrograding, and it is believed that these sediments were deposited in a
subaqueous fan (Metzger, 1979). There are no detrital biotite or muscovite
grains, possibly suggesting very rapid, turbulent deposition (Metzger, 1959;
Metzger and Bickford, 1972).
2.4. Shatter Zone
The perimeter of the Cadillac Mountain Granite is defined by the Shatter
Zone, an aureole of fragmented country rock that varies in apparent thickness
from 450-1000 m (Chapman, 1962; Gilman et al., 1988). The rock fragments in
the eastern Shatter Zone consist of: (1) Bar Harbor Formation; (2) Devonian
diorite dikes; and (3) large, relatively rare felsic volcanic xenoliths near the
8