| dc.description.abstract | Paleoraagnetic studies indicate the Meguma terrane's final
emplacement occurred between the Mid-Devonian and Early
Permian. Lithostratigraphic units near the boundary of the
terrane were investigated in order to provide constraints on
the timing of this compressional event.
North of the Cobequid-Chedabucto Fault (Guysborough Basin),
volcanic flows, pyroclastics and related sediments are
overlain by gravelly to sandy braided fluvial and lacustrine
lithofacies. East-southeast paleocurrents and variable (non-
Meguma) clast lithologies are typical of these units. South
of the Cobequid-Chedabucto Fault (St. Mary's Basin), coarse
cobble - rich to sandy braided fluvial lithofacies are
dominant. Paleocurrents indicate flow to the north and clast
lithologies are representative of the Meguma terrane.
Post Acadian (Late Devonian) basement fragmentation and
associated volcanism modified the area north of the Cobequid-
Chedabucto Fault. Basement block rotation, east end down,
initiated Latest Devonian through Mid-Carboniferous
sedimentation in a transtensile tectonic environment. There is no lithostratigraphic evidence to suggest the presence of
the Meguma terrane immediately south of the Guysborough Basin
during this time interval. However, the Meguma terrane was
supplying sediment to the St. Mary's Basin by the Early
Carboniferous. Collision and wrench faulting probably
initiated formation of this basin in a transtensile tectonic
environment. Subsequent dextral displacement along the
Cobequid-Chedabucto Fault and transpressive tectonic
conditions resulted in the removal of slices of both the St.
Mary's and GUysborough Basins as these two distinct
assemblages were juxtaposed. | |
