Publications

The documented presence of two large (~100-km diameter), possibly coeval impact craters of late Eocene age, requires modification of the impact-kill curve proposed by David M. Raup. Though the estimated meteorite size for each crater alone is large enough to have produced considerable global environmental stress, no horizons of mass mortality or pulsed extinction are known to be...

Siliceous microfossil assemblage succession was analyzed in a 100 m sediment core from Lake Baikal, Siberia. The core was recovered from the lake's central basin at a water depth of 365 m. Microfossil abundance varied greatly within the intervals sampled, ranging from samples devoid of siliceous microfossils to samples with up to 3.49 x 1011 microfossils g-1 sediment. Fluctuations in...

This paper summarizes the results of a comparative bathymetric study encompassing 150 km of the Louisiana barrier-island coast. Bathymetric data surrounding the islands and extending to 12 m water depth were processed from three survey periods: the 1880s, the 1930s, and the 1980s. Digital comparisons between surveys show large-scale, coherent patterns of sea-floor erosion and accretion...

Time series measurements of current velocity, depth and suspended-solids concentration (SSC) were used to obtain suspended-solids fluxes (SSF) during the fall at central Honker Bay and Spoonbill Creek. A wind-induced shear stress increases SSF out of Honker Bay through Spoonbill Creek by combining two effects: (1) wind-wave resuspension of bed sediments, and (2) wind shear raises the...

The activities of modern civilization have released to the oceans a wide variety of both mobilized natural compounds and synthetic compounds not found prior to modern times. Many of these compounds provide a means of identifying sources of inputs and pathways of movement of chemicals through oceanic ecosystems and serve as molecular markers of human activities. A coastal ocean (Tokyo Bay...

Massachusetts Bay is a shallow (35 m average depth) semienclosed embayment, roughly 100 ?? 50 km, which opens into the Gulf of Maine at its eastern boundary. Surface waves associated with winter storm winds from the northeast cause large sediment resuspension events, and wave and circulation fields during these events have a quasi-steady response to the wind stress. Coupled wave...

This study addresses ongoing concerns ever the effects of mobile fishing gear on benthic communities. Using side-scan sonar, bottom photographs and fishing records, we identified a set of disturbed and undisturbed sites on the gravel pavement area of northern Georges Bank in the northwest Atlantic. Replicate samples of the megofauna were collected with a 1 m Naturalists' dredge on 2...

Sediments from three cores obtained from distinct depositional environments in Lake Baikal, Siberia were analyzed for organic carbon, total nitrogen and lignin phenol concentration and composition. Results were used to examine changes in paleoenvironmental conditions during climatic cycles of the late Quaternary ( 125 ka). Average organic carbon, and total nitrogen concentrations, atomic...

High-resolution seismic, sidescan-sonar, multibeam bathymetry, and sediment sampling techniques were used to map the surficial geology and shallow subbottom stratigraphy of a segment of the inner shelf and nearshore region of New York-New Jersey metropolitan area. Preliminary analyses of these data provide a sedimentologic framework for addressing a wide range of science and management...

Until recently, Cenozoic evolution of the Atlantic Coastal Plain has been viewed as a subcyclical continuum of deposition and erosion. Marine transgressions alternated with regressions on a slowly subsiding passive continental margin, their orderly succession modified mainly by isostatic adjustments, occasional Appalachian tectonism, and paleoclimatic change. This passive scenario was...

Vatnajökull, Iceland, is the Earth’s most studied ice cap and represents a classical glaciological field site on the basis of S. Pálsson’s seminal glaciological field research in the late 18th century. Since the 19th century, Vatnajökull has been the focus of an array of glaciological studies by scientists from many nations, including many remote-sensing investigations since 1951...

A modeling study was undertaken to simulate the bottom tidal-, wave-, and wind-driven currents in Long Island Sound in order to provide a general physical oceanographic framework for understanding the characteristics and distribution of seafloor sedimentary environments. Tidal currents are important in the funnel-shaped eastern part of the Sound, where a strong gradient of tidal-current...