ABSTRACT
Sea-level changes have direct consequences for mankind; they profoundly
affect shallow-water deposition and erosion, nearshore ecosystems,
particle and nutrient transfer to the deep sea, and, at timescales of
decades to centuries, the evolution of coastal civilization. Determining
the timing, amplitudes, and causal mechanisms of sea-level variations, as
well as their relation to the resulting stratigraphic record, continues to
be a fundamental goal of the Ocean Drilling Program. Leg 174A will sample
as many as six locations along the New Jersey shelf and upper slope as
part of a long term initiative to investigate the Oligocene-Holocene
history of sea-level change in a transect across the continental margin
from the continental rise to the coastal plain. This initiative, the New
Jersey Mid-Atlantic Sea-Level Transect (MAT), combines the resources of
the Ocean Drilling Program, the National Science Foundation, and U.S. and
State of New Jersey geological surveys.
The primary goals of the transect are to (1) date unconformities (sequence
boundaries) of Oligocene to Holocene age and to compare this stratigraphic
record with the timing of glacial eustatic changes inferred from deep-sea
d18O variations, (2) place constraints on the amplitudes and rates of
sea-level change that may have been responsible for unconformity
development, (3) assess the relationships between depositional facies and
sequence architecture, and (4) to provide a baseline for future scientific
ocean drilling that will address the effects and timing of sea-level
changes on this and other passive margins. An additional objective for Leg
174A is technical. The leg represents the first attempt by the Ocean
Drilling Program to sample a thickly-sedimented continental margin in
water <200 m deep.
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