We report new ⁴⁰Ar/³⁹Ar ages for the oldest Pacific oceanic floor at Ocean Drilling Program Site 801C in the Pigafetta basin and Site 1149D close to the Izu-Bonin subduction zone in the Nadezhda basin. These ages were determined by applying high-resolution incremental heating experiments (including 15–30 heating steps) to better...
Over the last three decades the first-order correlation in morphology and orientation of seamount trails
has been called upon to support the concept of a ‘‘fixed’’ Pacific hot spot frame of reference and to explain
the Hawaii-Emperor bend (HEB) by a dramatic change in Pacific plate motion. In this paper,...
A granular controlled release formulation of 2 percent MCH was applied at 4.48 kg/ha to 76.9 ha of uninfested, windthrown Douglas-fir by helicopter with a modified aerial spreader of 1.12 m capacity in May 1982. Douglas-fir beetle population reduction was 96.4 percent by late June. With one exception, treated plots...
Cooperative Forestry and Pest Management conducted a pilot control project in central Montana to determine the effectiveness of two commercial formulations of BaaiUus th,uringiensis Berliner applied at 8 billiori international units (BIU) per acre (19.8 BIU per hectare) when used under operational conditions against the western spruce budworm, Choristoneu:roa ocaidentalis...
The volcanic origin of the Samoan archipelago can be explained by one of three models, specifically, by a hot spot forming over a mantle plume, by lithospheric extension resulting from complex subduction tectonics in the region, or by a combination of these two processes, either acting sequentially or synchronously. In...
Submersible exploration of the Samoan hotspot revealed a new, 300-m-tall, volcanic cone, named Nafanua, in the summit crater of Vailulu’u seamount. Nafanua grew from the 1,000-m-deep crater floor in <4 years and could reach the sea surface within decades. Vents fill Vailulu’u crater with a thick suspension of particulates and...
