K-Ar and ⁴⁰Ar-³⁹Ar geochronologic
data reveal the Paleocene to Eocene eruptive
history of volcanic centers which produced the
basaltic basement rocks of the Coast Range of
Oregon and Washington. Volcanism was short
lived at each center and migrated with time from
the northern and southern ends toward the
center, near...
Radiometric ages (K-Ar and ⁴⁰Ar-
³⁹Ar methods) have been determined on dredged
volcanic rocks from seven of the New England
Seamounts, a prominent northwest-southeast trending
volcanic lineament in the northwestern
Atlantic Ocean. The ⁴⁰Ar-³⁹Ar total fusion and
incremental heating ages show an increase in
seamount construction age from southeast to...
The Consortium of Universities for the Advancement of Hydrologic Sciences, Inc. (CUAHSI) began the Hydrologic Measurement Facility (HMF) program in June 2005 to advance hydrologic measurement capability within the research community. To provide guidance for this effort, a recent survey assessed the level of need among the hydrological sciences community...
Lavas of the Rano Rahi seamount field define a Nd-Pb-Sr isotopic array that connects, and substantially
overlaps, the arrays of the nearby East Pacific Rise axis and 5.6–28 Ma lavas of the Pukapuka ridge
system, situated between the seamount field and French Polynesia. Dating of Rano Rahi samples by
⁴⁰Ar-³⁹Ar...
Biological invasion potential can be strongly influenced by abiotic factors such as temperature, water availability, and solar radiation. Invasive species that possess phenotypically plastic traits can mediate impacts from these stressors, but may be unable to recognize and respond to dangerous levels in a novel environment. Understanding potential constraints on...
A volcanic event of immense scale occurred within a relatively short period in early Jurassic time over large regions of the contiguous Gondwana supercontinent. In southern Africa, associated remnants of thick volcanic successions of lava flows and extensive dike and sill complexes of similar composition have been grouped together as...
Results of ⁴⁰Ar–³⁹Ar Ar dating constrain the age of the submerged volcanic succession, part of the seaward-dip ping reflector sequence of the Southeast Greenland volcanic rifted margin, recovered during Leg 163. At the 3°Ne 6 drilling transect, the fully normally magnetized volcanic units at Holes 989B (Unit 1) and 990A...
A succession of basaltic lavas, volcaniclastic sediments, and lignite beds in the Holmatindur region of eastern Iceland provides the means for tying magnetic reversal stratigraphy and a record of major North Atlantic cooling to a precise radiometric timescale. A prominent part of the section is the Holmatindur classic bed, which...
We report the behavior of the earth's magnetic field for a transition recorded in lavas at the volcanic island of
Huahine in French Polynesia, south-central Pacific Ocean. Detailed intermediate fields are observed that record an
apparent N-N excursion. The available K-Ar ages indicate that most volcanic rocks of the southern...
In Fall 2006, a faculty member in George Washington University's University Writing 20 (UW20) program began incorporating service learning into her theme-based first-year writing course. Along with her librarian partner, they linked two research assignments to the service work of the students. An end-of-semester survey was administrated over three semesters...