A ca. 15 km thick succession of volcanic and sedimentary Neoproterozoi
c rocks are exposed within the Avalon Terrane of Newfoundland. Petrolo
gic and geochemical study of volcanic suites and sedimentological anal
yses indicate that most deposition took place in ensialic rift basins
and associated continental are settings. On the Avalon Peninsula, over
7500 m of volcaniclastic strata include initial submarine fan and slo
pe deposits, which pass upward into a prograded wedge of deltaic and f
luvial deposits. This flysch-to-molasse transition, and associated fol
ding and volcanism, mark the Neoproterozoic Avalonian Orogeny. Post-or
ogenic erosion was followed by deposition of extensive Cambrian silici
clastic deposits. Recent U-Pb zircon dating of many of the Neoproteroz
oic volcanic units provides some constraints on both intra-Avalon and
global correlations. More precise dates are needed to improve correlat
ion and better constrain the geologic history of this region. Glacioge
nic diamictites of the Gaskiers Formation exposed on the Avalon Penins
ula may eventually also prove useful for global correlation. Biostrati
graphic study of the latest Neoproterozoic-Lower Cambrian deposits has
resulted in ratification of the Precambrian-Cambrian Boundary Stratot
ype in an exposure on the Burin Peninsula. Older Neoproterozoic rocks
contain well-preserved Ediacara-type fossils and a low-diversity suite
of microfossils including acritarchs and carbonaceous filaments, the
latter of which have little biostratigraphic utility. Aside from work
on the Precambrian-Cambrian boundary section, little or no chemostrati
graphic, magnetostratigraphic or sequence stratigraphic work has been
completed on the Neoproterozoic of the Newfoundland Avalon Terrane.