Showing papers in "Earth and Planetary Science Letters in 1999"

TL;DR: In this paper, the authors report new Hf (and Nd) data for more than 100 sedimentary samples, recent to Archean in age, from a wide range of depositional environments.

TL;DR: Mafic to ultramafic dykes and sills in South China, dated as 828±7 Ma old, are identical in age to the 827±6 Ma Gairdner Dyke Swarm in Australia, thought to be of mantle plume origin this paper.

TL;DR: In this paper, a mixed scenario of active/passive rifting was proposed to account for these observations, and the authors found that an active component (a plume and resulting flood basalt) is a pre-requisite for the breakup of a major oceanic basin, but rifting must be allowed by plate-boundary forces and is influenced by preexisting heterogeneities in lithospheric structure.

TL;DR: In this article, a high resolution study of the oxygen and carbon isotopic composition (1500 measurement pairs) of speleothems from the Soreq cave, Israel, with chronology provided by 53 precise TIMS ages was performed.

TL;DR: In this article, the authors used tomographic imaging of the mantle under Tibet, India and the adjacent Indian Ocean to reveal several zones of relatively high P-wave velocities at various depths.

TL;DR: In this paper, the authors characterize a newly recognized mechanism of dewatering at convergent margins, where freshening of pore waters from hydrate destabilization at depth and free gas drives fluids upward.

TL;DR: In this paper, the authors investigated the influence of the Carnegie Ridge collision on the North Andean convergent margin and found that the collision has been occurring for at least 2 Ma based on the basement uplift signal along trench-parallel transects.

TL;DR: In this article, high resolution pollen, dinocyst and isotopic data for the Last Interglacial complex from marine core MD952042 (southwestern margin of the Iberian Peninsula; 37°48′N; 10°10′W; 3148 m) were presented.

TL;DR: In this article, the authors used culturing results and a core-top Neogloboquadrina pachyderma calibration to estimate glacial-interglacial changes in sea surface temperature (SST) using planktonic Mg/Ca records.

TL;DR: In this article, the age of metamorphic zircon rims from a hydrothermal vein is interpreted as dating the prograde formation of the vein at temperatures well below 550°C.

TL;DR: In this article, the authors used seasonal subsets of the global data base of temperature and isotopic measurements to represent two different climate modes and found that the relationship between mean annual temperature (MAT) and the weighted average oxygen isotope composition of yearly precipitation (δ18Opt) is uncertain.

TL;DR: The phase relationship between silicate melts and hydrous fluids was studied by direct visual observation in an externally heated diamond-anvil cell as mentioned in this paper, where complete miscibility of silicate melt and water was observed for a wide range of melt compositions, including nepheline, jadeite, dacite, haplogranite and Ca-bearing granite.

TL;DR: This article measured partition coefficients for U, Th, REE, and high field strength element for orthopyroxene-liquid (3) and garnet-liquid pairs from 2.4 to 2.8 GPa.

TL;DR: In this paper, the authors presented tomographic images of a narrow low velocity anomaly below Iceland, extending from the core-mantle boundary to the surface, and inferred a bent plume with a diameter ≤500 km, rising from a broad root zone (>1000 km) and culminating in a plume top with diameter of ∼1200 km.

TL;DR: In this article, the authors study the dynamics of melting in the Hawaiian plume using a 3D variable-viscosity convection model outfitted with a melting parameterization that permits calculation of the local melting rate and the distribution of buoyant depleted residual material.

TL;DR: In this paper, the authors present direct evidence of the rare earth elements isotopic exchange between particulate lithogenic fraction and seawater without significant mass transfer, and suggest that the partial dissolution of atmospheric fallout is probably one of the main rare earth element sources of the ocean.

TL;DR: In this paper, the authors evaluate the effects of varying prograde P-T paths on the magnitudes of devolatilization and chemical/isotopic alteration of subducting rocks.

TL;DR: In this article, the results of a clay mineralogy study combined with major element geochemistry, strontium, neodymium and oxygen isotopes, and 14C AMS stratigraphy are reported for deep-sea gravity cores located in the Bay of Bengal (MD77-180) and the Andaman Sea (MD 77-169).

TL;DR: Seawater Sr and Ca exhibit spatial gradients of 2-3% globally, with the deep ocean more enriched relative to the surface as mentioned in this paper, and the highest surface values are found at high latitudes and associated with areas of upwelling.

TL;DR: In this article, the effect of deformation regime on the development of olivine lattice-preferred orientations (LPO) and associated seismic anisotropy within continental deformation zones is investigated.

TL;DR: In this paper, Coney et al. show that the variation in exhumation patterns is controlled by a change in how convergence is accommodated within the Pyrenean double-wedge.

TL;DR: A suite of tholeiitic picrites from eight of the younger (<2 Ma) Hawaiian shield volcanoes provides new information about the compositions of primitive magmas and source components in the Hawaiian plume as mentioned in this paper.

TL;DR: For example, in this paper, the authors obtained the first estimates of the Os isotope composition of Jurassic seawater from three suites of immature, organic-rich mudrocks from Jurassic coastal outcrops in England.

TL;DR: In this article, the authors investigated the ascent rates required to maintain bubble-melt equilibrium in high-silica rhyolitic melts at 200 MPa and 825°C, and decompressed to lower pressures at constant rates of 0.025, 0.25,0.5, and 1.0 MPa s−1.

TL;DR: This paper measured the trace elements B, Mg, Sr, Ba and U in a high-latitude coral colony (Porites lobata) taken from Shirigai Bay, Japan (32°N).

TL;DR: In this article, high precision 186Os/188Os measurements for these picrites, combined with previous analyses, show that the Hawaiian plume source has 186Os and188Os that range from chondritic mantle values of ∼ 0.119834 to more radiogenic values as high as ∼0. 119848.

TL;DR: The geochemical implications of thermally driven flow of seawater through oceanic crust on the mid-ocean ridge flank have been examined on a well-studied 80 km transect across the eastern flank of the Juan de Fuca Ridge at 48-N, using porewater and basement fluid samples obtained on ODP Leg 168.

TL;DR: In this article, the authors extended Dodson's formulation to include cases with arbitrarily small amount of diffusion, and applied it to calculate TC and age profiles, which would develop in single crystals of different geometries.

TL;DR: In this article, an exceptionally well-constrained Sm−Nd isotope data from garnets in ultrahigh pressure (coesite-bearing) eclogite from the Western Alps were obtained to determine the age of peak metamorphism and exhumation rates of deeply buried oceanic crust in the Zermatt-Saas ophiolite complex.