Index Catalog // ScholarsArchive@OSU

Creator:: Duncan, Robert A.
Abstract:: 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...
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Full Text:: Seamcunt Age Progression 9981 Corner Seamcunts 38 0 • GOSHOLD _ •Rehoboth •-----• .'•"J ALLEGHENY vog

Creator:: Miller, Robert N.
Abstract:: A series of observing system simulation experiments (OSSE) is performed on a simulated data set which was designed to mimic the wind-forced response of the tropical Pacific ocean. This data set was constructed by adding random perturbations to the FSU monthly mean pseudostress anomaly data. These perturbed pseudostress anomaly fields...
Resource Type:: Article
Full Text:: ROBERT N. MILLER College of Oceanography, Oregon State University, Corvallis A series of observing

Creator:: Duncan, Robert A.
Abstract:: 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...
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Full Text:: CAPTURED ISLAND CHAIN IN THE COAST RANGE OF OREGON AND WASHINGTON Robert A. Duncan School of

Creator:: Chauvin, Annick, Roperch, Pierrick, and Duncan, Robert A.
Abstract:: A volcanic sequence almost 700 meters thick has been sampled in the Punaruu valley on the island of Tahiti, southern central Pacific Ocean. Detailed paleomagnetic results have been obtained from 123 sites. Three reversals are recorded in this sequence. Age determinations (K-Ar) indicate that the youngest reversal corresponds to the...
Resource Type:: Article
Full Text:: , Universitd de Rennes I, Rennes, France ROBERT A. DUNCAN College of Oceanography, Oregon State University

Creator:: Pyle, D. G., Christie, David M., Mahoney, J. J., and Duncan, Robert A.
Abstract:: Within the Australian-Antarctic Discordance (AAD), a boundary exists between isotopically defined “Pacific-type” and “Indian-type” mid-ocean ridge basalt (MORB) erupted along the Southeast Indian Ridge (SEIR). This boundary has migrated westward beneath the easternmost AAD spreading segment at a minimum rate of 25 mm/yr since 4 Ma; however, its long-term history...
Resource Type:: Article
Full Text:: University, Corvallis J. J. Mahoney Department of Geology and Geophysics, Woods Hole Oceanographic

Creator:: Puleo, J. A., Beach, R. A., Holman, Robert A., and Allen, J. S.
Abstract:: A study of swash zone sediment transport was conducted at Gleneden Beach, Oregon during February 25-28, 1994. The data collected included suspended sediment concentration (SSC), sea surface elevation, and velocity (initially 4 and 8 cm above the bed) at three cross-shore locations within the swash zone spanning high tides. Ensemble...
Resource Type:: Article

Creator:: Duncan, Robert A., Hooper, P. R., Rehacek, J., Marsh, J. S., and Duncan, A. R.
Abstract:: 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...
Resource Type:: Article
Full Text:: timing and duration of the Karoo igneous event, southern Gondwana R.A. Duncan, • P.R. Hooper,: J

Creator:: Kruse, Sarah E., Liu, Zhengrong J., Naar, David F., and Duncan, Robert A.
Abstract:: Bathymetry and gravity data collected during Legs 5, 6, and 7 of the 1993 GLORIA Expedition and the recently released 2-min altimetry-derived global gravity grid are used to determine the effective elastic thickness of the lithosphere along the Easter Seamount Chain (ESC). Forward modeling, admittance, and coherence methods yield consistent...
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Full Text:: Department, University of South Florida, Tampa Zhengrong J. Liu • and David F. Naar Marine Science

Creator:: Beardsley, Robert C., Denver, Edward P., Lentz, Steven J., and Dean, Jerome P.
Abstract:: Surface heat flux components are estimated at a midshelf site over the northern California shelf using moored measurements from the 1981-1982 Coastal Ocean Dynamics Experiment (CODE) and the 1988-1989 Shelf Mixed Layer Experiment (SMILE). Time series of estimated fluxes extend from early winter through summer upwelling conditions, allowing examination of...
Resource Type:: Article
Full Text:: Surface heat flux variability over the northern California shelf Robert C. Beardsley Department of

Creator:: Foster, D. L., Bowen, A. J., Holman, Robert A., and Natoo, P.
Abstract:: Recently, models for the onshore migration of nearshore sandbars were improved by including an empirical acceleration term in the sediment transport formulation (Hoefel and Elgar, 2003). Here, field observations of the fluid-sediment interface suggest that the success of this empirical parameter may result from unsteady forcing of sediment beds by...
Resource Type:: Article
Full Text:: incipient motion D. L. Foster,1 A. J. Bowen,2 R. A. Holman,3 and P. Natoo1 Received 31 December 2004

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