Environmental magnetic techniques have been used to discriminate sources of sediments from a variety of natural and anthropogenic sources. In many studies, magnetic properties such as susceptibility, have served as a proxy for heavy metal concentrations. In these cases, there tends to be enhancement of magnetic minerals. The study presented...
Sedimentary records from the North Atlantic, instrumental in the development of modern paleo-geomagnetic concepts, show a highly variable field even during times of constant polarity. Yet, our understanding of how the magnetization is acquired in the sediments is poorly understood. Primary magnetizations preserved in deep-sea sediments are known to be...
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Joseph S. Stoner
Sedimentary records from the North Atlantic, instrumental in the
Burial Lake sediments from the Noatak Basin in the northwest Brooks Range of Arctic Alaska (68.43°N, 159.17°W, 21.5 m water depth) provide the oldest continuous lacustrine record of paleo-environmental change and paleomagnetic secular variation (PSV) in eastern Beringia. A precise radiocarbon chronology, determined through accelerator mass spectrometry (AMS) allows us...
This research presents a u-channel based study of the natural remanent magnetization (NRM), the laboratory magnetization, Anhysteretic Remanent Magnetization (ARM), and magnetic susceptibility (k), from the upper 100 m of International Ocean Discovery Program (IODP) Expedition 383 Site U1543 in the eastern South Pacific sector of the Southern Ocean. Alternating...
Stratigraphy and chronology are essential to sedimentological study of Earth system histories. And, stratigraphy and chronology are often challenging and interesting problems themselves. The Quaternary (2.588 Ma - present) experienced paleoenvironmental and paleo-geomagnetic variability well outside the range of the recent instrumental record, providing the opportunity to place recent observations...
Disentangling sediment source from sediment transport is a fundamental marine geologic challenge critical to the interpretation of any sedimentary record. The Eirik Ridge, a sediment drift south of Greenland, receives terrigenous sediment primarily from subglacial erosion of south Greenland’s Precambrian bedrock and Paleogene volcanics that outcrop in east Greenland and...
Aerobic organisms have evolved many sensory mechanisms that allow
response to oxidants in the environment. One area of interest is the relationship
between the activity of the tumor suppressor protein p53 and the redox state of
thioredoxin. Human p53 activity is severely compromised in budding yeast lacking
thioredoxin reductase. Evidence...
An apparatus and procedure are described for investigating
selective adsorption from a binary vapor mixture as a function of
pressure. The technique measures both total mass adsorption and
adsorbed-phase composition.
Development of the method is outlined. Possible sources of
error are analyzed and are found to be either nonexistent or...
The Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM) requires that Final Status Surveys be performed on materials and surfaces that vary in surface smoothness and/or uniformity. To obtain accurate survey data, it may be necessary to adjust detector response for these surface variations. NUREG-1507 refers to such surface efficiency...