AN INTEGRATED MAGNETOSTRATIGRAPHIC AND
PALEOLATITUDINAL FRAMEWORK FOR THE LATE
TRIASSIC NEWARK SUPERGROUP
KENT, Dennis V., and OLSEN, Paul E., Lamont-Doherty
Earth Observatory, Columbia University, Palisades,
NY, 10964
An astronomically calibrated geomagnetic polarity time scale and
paleolatitudinal record have been developed from a complete section
obtained by scientific coring in the Newark Basin. The paleomagnetic
data from the Newark section show 59 polarity intervals and
northward motion of about 7° (2.5° to 9.5° North) over 30 million
years, providing a spatiotemporal framework for high resolution
correlation and paleogeographic analysis in the Late Triassic.
We illustrate the utility of this integrated reference sequence in
studies of several other Newark rift basins, including a ~3000 meter
exposed section of the Leakesville Formation of mainly Carnian age
from the Dan River/Danville Basin, and in preliminary results from a
~300 m cored section of the Blomidon Formation of Norian-
ēRhaetianē age from the Fundy Basin. There is a very close match in
polarity stratigraphies between the Dan River/Danville and Newark
Basins, confirming the general age-equivalence of the thick upper
Cow Branch Member of the Leakesville Formation and the Lockatong
Formation. Paleopoles from the coeval intervals also agree, indicating
that there has been no significant vertical-axis tectonic rotations
between these distant basins. The preliminary magnetostratigraphic
data from the Blomidon Formation suggest that this unit encompasses
the age-equivalent of the upper half of the Passaic Formation,
implying that the average sedimentation accumulation rate in this part
of the Fundy section (~30 m/m.y.) was considerably lower than in the
Newark section (~200 m/m.y.). These and related results that
combine magnetostratigraphic correlation and cycle stratigraphy in a
paleolatitudinal context are providing a powerful means to chart the
development of continental lithofacies in terms of paleoclimate and
local tectonic controls, and to improve paleogeographic
reconstructions of Pangea in general.
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