Index Catalog // ScholarsArchive@OSU

A captured island chain in the coast range of Oregon and Washington

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...
Resource Type:: Article
Full Text:: CAPTURED ISLAND CHAIN IN THE COAST RANGE OF OREGON AND WASHINGTON Robert A. Duncan School of

Age progressive volcanism in the New England seamounts and the opening of the Central Atlantic Ocean

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...
Resource Type:: Article
Full Text:: ATLANTIC OCEAN R. A. Duncan College of Oceanography, Oregon State University, Corvallis Abstract

Spatial and temporal distribution of a C-like asthenoshpheric component in the Rano Rahi Seamount Field, East Pacific Rise, 15°-19°S

Creator:: Hall, L. S., Mahoney, J. J., Sinton, J. M., and Duncan, Robert A.
Abstract:: 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...
Resource Type:: Article
Full Text:: 2006. Hall, L. S., J. J. Mahoney, J. M. Sinton, and R. A. Duncan (2006), Spatial and temporal

The timing and duration of the Karoo igneous event, southern Gondwana

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

⁴⁰Ar-³⁹Ar chronology for the volcanic history of the Southeast Greenland rifted margin

Creator:: Tegner, Christian and Duncan, Robert A.
Abstract:: 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...
Resource Type:: Article
Full Text:: SOUTHEAST GREENLAND RIFTED MARGIN Lar sen, H.C., Duncan, R.A., Allan, J.F., Brooks, K. (Ed s.), 1999

Precise dating of the Holmatindur cooling event in eastern Iceland: Evidence for mid-Miocene bipolar glaciation

Creator:: Duncan, Robert A. and Helgason, J.
Abstract:: 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...
Resource Type:: Article
Full Text:: eastern Iceland: Evidence for mid-Miocene bipolar glaciation R. A. Duncan College of Oceanic and

Records of geomagnetic reversals from volcanic islands of French Polynesia 1. Paleomagnetic study of a polarity transition in a lava sequence from the island of Huahine

Creator:: Roperch, Pierrick and Duncan, Robert A.
Abstract:: 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...
Resource Type:: Article
Full Text:: Gdophysique Interne, Universitd de Rennes I, Rennes, France ROBERT A. DUNCAN College of Oceanography

Distribution of recent volcanism and the morphology of seamounts and ridges in the GLIMPSE study area: implications for the lithospheric cracking hypothesis for the origin of intraplate, non-hotspot volcanic chains

Creator:: Forsyth, Donald W., Harmon, Nicholas, Scheirer, Daniel S., and Duncan, Robert A.
Abstract:: Lithospheric cracking by remotely applied stresses or thermoelastic stresses has been suggested to be the mechanism responsible for the formation of intraplate volcanic ridges in the Pacific that clearly do not form above fixed hot spots. As part of the Gravity Lineations Intraplate Melting Petrology and Seismic Expedition (GLIMPSE) project...
Resource Type:: Article
Full Text:: plays at most a secondary role. Citation: Forsyth, D. W., N. Harmon, D. S. Scheirer, and R. A. Duncan

Radiometric ages for basement rocks from the Emperor Seamounts, ODP Leg 197

Creator:: Duncan, Robert A. and Keller, Randall A.
Abstract:: The Hawaiian-Emperor seamount chain is the ‘‘type’’ example of an age-progressive, hot spotgenerated intraplate volcanic lineament. However, our current knowledge of the age distribution within this province is based largely on radiometric ages determined several decades ago. Improvements in instrumentation, sample preparation methods, and new material obtained by recent drilling...
Resource Type:: Article
Full Text:: 1.1-Ga rhyolite, Geochim. Cosmochim. Acta, 64, 73–98. Pringle, M. S., and R. A. Duncan (1995

⁴⁰Ar-³⁹Ar ages of lavas from the Southeast Greenland margin, ODP leg 152, and the Rockall Plateau, DSDP leg 81

Creator:: Sinton, Christopher W. and Duncan, Robert A.
Abstract:: ⁴⁰Ar-³⁹Ar incremental heating experiments were performed on volcanic rocks recovered by drilling during Ocean Drilling Program Leg 152, southeast Greenland Margin (63°N), and Deep Sea Drilling Project Leg 81, southwest Rockall Plateau (56°N). Both of these legs drilled into thick sections of submerged lava flows, known as seaward-dipping reflector sequences,...
Resource Type:: Article
Full Text:: C.W. SINTON, R.A. DUNCAN 8 ou ) in a e s on n ar o e . - L th i p d R the ed- ial of

ScholarsArchive@OSU

A captured island chain in the coast range of Oregon and Washington

Age progressive volcanism in the New England seamounts and the opening of the Central Atlantic Ocean

Spatial and temporal distribution of a C-like asthenoshpheric component in the Rano Rahi Seamount Field, East Pacific Rise, 15°-19°S

The timing and duration of the Karoo igneous event, southern Gondwana

⁴⁰Ar-³⁹Ar chronology for the volcanic history of the Southeast Greenland rifted margin

Precise dating of the Holmatindur cooling event in eastern Iceland: Evidence for mid-Miocene bipolar glaciation

Records of geomagnetic reversals from volcanic islands of French Polynesia 1. Paleomagnetic study of a polarity transition in a lava sequence from the island of Huahine

Distribution of recent volcanism and the morphology of seamounts and ridges in the GLIMPSE study area: implications for the lithospheric cracking hypothesis for the origin of intraplate, non-hotspot volcanic chains

Radiometric ages for basement rocks from the Emperor Seamounts, ODP Leg 197

⁴⁰Ar-³⁹Ar ages of lavas from the Southeast Greenland margin, ODP leg 152, and the Rockall Plateau, DSDP leg 81

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