Sedimentology, Ichnology, and Depositional History of the Contact Between the Triassic Montney and Doig Formations in
LaMothe, Jon T.1,
M.K. Gingras1, S.G. Pemberton1 (1)
In most locations the boundary between
the lower and middle Triassic Montney and Doig formations of
Detailed analysis reveals that the lower
unconformity bound wedge (E1-E2) contains sandy silts relating to deeper water facies, while the overlying sandy unconformity bound wedge
(E2-E3) contains heavily bioturbated offshore to
delta front facies. Sedimentary structures and ichnology help with interpretation of the Moig Siltstone Unit while only ichnology
can be used on the Moig Sandstone Unit due to the
high abundance of trace makers eradicating any previous structures. Mapping of
the Moig Sandstone Unit shows numerous semicircular
sand lobes. This is due to original depositional characteristics being planed
off by the overlying erosive submarine event (E3), which was followed by a
period of non-deposition creating phosphates. Since mapping of this unit shows
no paleo-depositional history, core analysis is the
main method of arriving at a depositional model. Through this analysis there is
the recognition of offshore to delta front traces. This study concludes that a
relatively shallow marine setting was present for the upper portion of the Moig Sandstone Unit when compared to other shallow marine ichnology models.
AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California