Index Catalog // ScholarsArchive@OSU

Geochemistry and geochronology of ancient southeast Indian and southwest Pacific seafloor

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:: seafloor D. G. Pyle and D. M. Christie College of Oceanic and Atmospheric Sciences, Oregon State

Five million years of compositionally diverse, episodic volcanism : construction of Davidson Seamount atop an abandoned spreading center

Creator:: Clague, D. A., Paduan, J. B., Duncan, Robert A., Huard, J. J., Davis, A. S., Castillo, P. R., Lonsdale, P., and DeVogelaere
Abstract:: Davidson Seamount, a volcano located about 80 km off the central California coast, has a volume of ~320 km³ and consists of a series of parallel ridges serrated with steep cones. Davidson was sampled and its morphology observed during 27 ROV Tiburon dives. During those dives, 286 samples of lava,...
Resource Type:: Article
Full Text:: , episodic volcanism: Construction of Davidson Seamount atop an abandoned spreading center D. A. Clague and

Erosion by rivers and transport pathways in the ocean: A provenance tool using 40Ar--39Ar incremental heating on fine-grained sediment

Creator:: VanLaningham, Sam, Duncan, Robert A., and Pisias, Nicklas G.
Abstract:: We use Ar-40-Ar-39 incremental heating to fingerprint bulk fluvial sediment entering the northeast Pacific Ocean, with the long-term intent of tracking sediment source and transport changes from the terrestrial system to the marine environment through time. We show reproducible age spectra from individual rivers accounting for the majority of sediment...
Resource Type:: Article
Full Text:: McDougall and Harrison [1999]). 40Ar loss is evidenced by ever increasing ages in the low-temperature steps

⁴⁰Ar/³⁹Ar geochronology of silicic and basic volcanic rocks on the margins of the North Atlantic

Creator:: Sinton, C. W., Hitchen, K., and Duncan, Robert A.
Abstract:: At the submerged margins of the North Atlantic, andesitic to dacitic and basaltic volcanic rocks occur together. The silicic rocks were derived by processes requiring the presence of continental crust (crustal anatexis and/or contamination of mafic magmas) while the majority of the basaltic lavas had little or no contact with...
Resource Type:: Article
Full Text:: C. W. S I N TO N, K. H I T C H E N & R. A. D U N C A N Figure 1. Schematic map of the North

High-resolution ⁴⁰Ar/³⁹Ar dating of the oldest oceanic basement basalts in the western Pacific basin

Creator:: Koppers, Anthony A. P., Staudigel, Hubert, and Duncan, Robert A.
Abstract:: 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...
Resource Type:: Article
Full Text:: ts a D ep th , m b sf S am p le T y p e S tu d y Id en ti fi er A n al y si s T y p e A g e

The Cobb-Eickelberg seamount chain : hotspot volcanism with mid-oean ridge basalt affinity

Creator:: Desonie, Dana L. and Duncan, Robert A.
Abstract:: Cobb hotspot, currently located beneath Axial seamount on the Juan de Fuca ridge, has the temporal but not the isotopic characteristics usually attributed to a mantle plume. The earlier volcanic products of the hotspot, from eight volcanoes in the Cobb-Eickelberg seamount (CES) chain, show a westward age progression away from...
Resource Type:: Article
Full Text:: PACIFIC PLATE contour interval = 400 ß /Miller Seamount athflnder •/'d•8..mount T. Horton Guyot

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:: composition of Ar released at each step [e.g., Dalrymple et al., 1981' McDougall and Harrison, 1988

Effective elastic thickness of the lithosphere along the Easter Seamount Chain

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...
Resource Type:: Article
Full Text:: convection roll [Bonani and Harrison, 1976; Bonatti et al., 1977], a "leaky fracture zone" model [Clark and

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:: the seawar d-dip ping r eflector sequence of the Southeast Gr eenland volcanic rift ed margin, r

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

Geochemistry and geochronology of ancient southeast Indian and southwest Pacific seafloor

Five million years of compositionally diverse, episodic volcanism : construction of Davidson Seamount atop an abandoned spreading center

Erosion by rivers and transport pathways in the ocean: A provenance tool using 40Ar--39Ar incremental heating on fine-grained sediment

⁴⁰Ar/³⁹Ar geochronology of silicic and basic volcanic rocks on the margins of the North Atlantic

High-resolution ⁴⁰Ar/³⁹Ar dating of the oldest oceanic basement basalts in the western Pacific basin

The Cobb-Eickelberg seamount chain : hotspot volcanism with mid-oean ridge basalt affinity

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

Effective elastic thickness of the lithosphere along the Easter Seamount Chain

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

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

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