Publications

Petrologic and sulfur isotopic studies have been carried out on drill core samples from a roll-type uranium deposit in the mid-Tertiary Catahoula Tuff, Webb County, south Texas. Epigenetic iron disulfide minerals formed in two distinct stages. The first stage involved sulfidization of the host rock by sulfide (H 2 S, HS-)-bearing solutions that emanated from a fault about 1.5 km downdip...

Paleomagnetic results from 17 magnetically stable units of Upper Cretaceous (‘Andean’) plutons and dikes of the Lassiter Coast, on the southern Antarctic Peninsula, define a mean paleomagnetic pole at 87°S, 131°W (α95 = 11.5°). This indicates that little latitudinal movement of the southern Antarctic Peninsula has occurred during the past 100 m.y. All magnetically stable intrusives are...

Oneida Lake is a large, shallow, eutrophic lake situated in the Ontario lowlands of central New York State. It contains the most concentrated deposit of freshwater ferromanganese nodules (in terms of amount per unit area) yet reported in the literature. The mineralogy and bulk chemistry of these saucer-shaped nodules are similar to the mineralogy and bulk chemistry of deep-sea...

Two of the three ash flow tuffs of the Yellowstone Group are stably magnetized throughout their extent: the Lava Creek tuff (0.60 m.y.) in a normal direction and the Mesa Falls tuff (1.22 m.y.) in a reversed direction. In contrast, much of the Huckleberry Ridge tuff, which was erupted during a polarity transition or field excursion 1.92 m.y. ago and initially magnetized in an...

Interdisciplinary field studies and remote sensing techniques were used to delineate mountain areas in Colorado subject to such natural hazards as snow avalanches, mudflows, rockfalls, and landslides. The old mining townsite of Ophir in the northwestern San Juan Mountains was used as a case study. Its serious snow avalanche hazard has been made even more critical with prospects of new...

Radiocarbon dates and stratigraphic cores from bogs, kettle ponds, and former ice-marginal lakes on the east and west sides of the Front Range, Colo., between lat 40°00' and 40°24' N. suggest that (1) valley glaciers of Pinedale age began to recede from their terminal positions between about 14,600 and 13,000 yr ago, (2) revegetation of glaciated areas at altitudes of 2,600-2,900 m (8...