Results 261 to 270 of about 457,724 (300)

Seismic Structure of the Southern East Pacific Rise

Science, 1993
Seismic data from the ultrafast-spreading (150 to 162 millimeters per year) southern East Pacific Rise show that the rise axis is underlain by a thin (less than 200 meters thick) extrusive volcanic layer (seismic layer 2A) that thickens rapidly off axis.
R S, Detrick, A J, Harding, G M, Kent, J A, Orcutt, J C, Mutter, P, Buhl   +5 more
openaire   +2 more sources

East Pacific Rise Crest: A Near-Bottom Geophysical Profile

Science, 1969
A deep-towed magnetometer profile made across the East Pacific Rise crest shows many anomalies with about 1000-gamma amplitudes and 500-meter wavelengths and has larger amplitude changes corresponding to magnetic field reversals. This profile across contacts between normal and reversely magnetized crustal blocks is interpreted to place an upper limit ...
R L, Larson, F N, Spiess
openaire   +2 more sources

On the spreading of the East Pacific Rise

Tectonophysics, 1990
Abstract We analyze through statistical methods the mechanics of the East Pacific Rise by considering the relative angular velocities of spreading of the Pacific-Nazca, Pacifie-Cocos and Pacific-Rivera margins. We focus our attention on verifying the validity of some issues such as the constancy of the velocity of spreading, the symmetry of the ...
Marzocchi, W., Mulargia, F.
openaire   +2 more sources

Uranium Rich Sediments on the East Pacific Rise

Nature, 1969
SEDIMENTS on mid-ocean ridges associated with ocean floor spreading and high heat flow are poor in Al, Ti, Si, Cu, Co, Ni and rare earth elements, and enriched in Fe, Mn, V, Cd, Hg, As, B, Cr, Ba and P, compared with other pelagic sediments. The origin of these distribution patterns is not fully understood but is most likely the result of volcanic ...
DAVID E. FISHER, KURT BOSTROM
openaire   +1 more source

A226Ra section across the East Pacific Rise

Earth and Planetary Science Letters, 1980
Abstract Four vertical Ra profiles have been measured across the East Pacific Rise (EPR) from Callao to Tahiti. These profiles show that Ra in the deep water (below 2 km depth) increases toward the EPR. However, this increase does not necessarily indicate a Ra source on the EPR.
openaire   +1 more source

Late Tertiary date from the East Pacific Rise

Journal of Geophysical Research, 1967
A potassium-argon date from a basalt boulder dredged from a seamount near the crest of the northern extension of the East Pacific rise is 27±6 m.y. This note presents evidence for the association of Cobb seamount and its geologic age with the axial zone of the East Pacific rise.
Thomas F. Budinger, Betty J. Enbysk
openaire   +1 more source

Stauromedusae on the East Pacific Rise

2006
Dense aggregations of the large stauromedusae Lucernaria janetae Collins & Daly, 2005 are known from four sites near East Pacific Rise hydrothermal vents, but as is typical of circum-vent animals, their biology remains virtually unstudied. Observations of stauromedusae from near 8°36'N find that they are consistently near fissures from which warm,
openaire   +1 more source

Sea-floor lava fields on the East Pacific Rise

Deep Sea Research Part B. Oceanographic Literature Review, 1985
A SeaBeam and SeaMARC I survey of a seamount group located several kilometres west of the axis of the East Pacific Rise (EPR) at lat 9°53′N defines the existence of a large submarine lava field at the base of one of the volcanoes (MIB). The field must be relatively young with respect to the surrounding terrain because lavas lap up against the base of ...
Daniel J. Fornari, William B. F. Ryan, Paul J. Fox   +2 more
openaire   +2 more sources

Metal accumulation rates in East Pacific Rise metalliferous sediments

Marine Geology, 1983
Abstract Metal accumulation rates at a number of stations on the East Pacific Rise fracture zone at 9°S are determined and their areal variations are examined. The accumulation rates of Mn, Fe, Cu, Zn and Ni show their highest values at the Rise crest—fracture zone intersection with zones of lower accumulation rates around this site.
S.P. Varnavas, J. Papaioannou
openaire   +1 more source

Small off-axis volcanoes on the East Pacific Rise

Earth and Planetary Science Letters, 1996
Abstract A study of Sea Beam bathymetry and SeaMARC II side-scan sonar data allows a quantitative measure of the contribution of off-axis volcanism to the creation of abyssal hill topography on the East Pacific Rise (EPR) 9°15′N–9°50′N. In order to assess the role of off-axis volcanism, the distribution of volcanic edifices within 35 km of the ridge ...
Russ T. Alexander, Ken C. Macdonald
openaire   +1 more source