Abstract:
North Amerlc8 W8S inundated by fJ major eplcontlnental sea during
ihe C:retaceo.us Period. The sOljihw6rd transgression of th.e northern Boreal
See along the ~\festern Interior Seaway resulted in a meetlng with the
northward edv6nclng waters from the GUlf of Mexico (Obradovich and
Cobban, 1975). Th1s link was 1n eXlstence by late Albien time and 6llowed
for the comm1ngl1ng of the prol1ferous Arctic and Gulf rnar1ne faunas (F1g.
1). By early Campanlan time, there was a widening of B6ffln Bay wlth a
slrnult8neous subsidence 1n the Arct1c Archlpelago and Sverdrup 6as1n
(W11liam and Stelck, 1975). Williams and Burk (1964) found 6 break 1n the
marines sedlmentatlon in the f1anltoba area, suggesting Bland corlnectlon
from the Dlstrlct of Keewatln through eastern M6fl1toba to the lake
Sl~perlor reglon, lmplying that the only dlrect connection between the
Interlor Sea with Baffln Bay, was yia the Arct1c.
This hiatus was also documented by Meek and Hayden (1861) ln the
United states between the Niobrara and Pierre Format1ons. Jeletzky (1971)
suggested that the retreat of the sea towards the east was by a serles of
strong pulses resultlng in the regression of the Campanlan and
M66str1chtlan seas. During ttle Cretaceous1 the r1s1ng Corl1111era caused the
western shoreline of the Interlor Sea to migrate eastwards and the
Cordillera'l detritus produced deltaic cornplexes from the Mackenzie Valley
to Ne\N Mexlcoo The foreland basin was continually subslding and thls
down\",arplng aided in the eastward m1gration of the western shorel1ne.
Thls also lndicates that trle water 'tIes becom1ng deeper in the central
Plains sect10n of the Seaway (Fig. 2).
