Showing papers in "Earth and Planetary Science Letters in 2003"

TL;DR: The origin of mantle hotspots is a controversial topic as mentioned in this paper, and only seven (primary) out of 49 hotspots meet criteria aimed at detecting a very deep origin (three in the Pacific, four in the Indo-Atlantic hemisphere).

TL;DR: A wide range of geophysical and geological data indicate that extensive serpentinization in the forearc mantle is both expected and observed as discussed by the authors, and that large volumes of aqueous fluids must be released upwards by dehydration reactions in subducting oceanic crust and sediments.

TL;DR: In this article, a review of the implications of multiple isotope studies is presented, focusing on anomalous, but not uncommon isotopic signatures of sulfur in the geologic record.

TL;DR: In the last decade apatite (U-Th)/He thermochronometry has emerged as an important tool for quantifying the cooling history of rocks as they pass through the upper 1-3 km of the crust as discussed by the authors.

TL;DR: In this paper, the authors numerically modeled this parodoxically interesting geological phenomenon, in which rising diapiric structures, colder than the asthenosphere by 300-400°C, are driven upward by compositional buoyancy, with a high-resolution two-dimensional regional model.

TL;DR: More and more evidence is being discovered in Phanerozoic collision belts of the burial of crustal rocks to previously unsuspected (and ever increasing) depths, presently on the order of 150-200 km, and of exhumation from such depths as mentioned in this paper.

TL;DR: In this article, the authors report on laboratory experiments designed to investigate the frictional behavior of natural and synthetic clay-rich gouges, and they show that the velocity-strengthening behavior of illite shale under a wide range of conditions, do not support the hypothesis that the smectite-illite transition is responsible for the seismic-aseismic transition in subduction zones.

TL;DR: In this paper, high-precision isotope ratios of dissolved Mo in seawater from different ocean basins and depths show a homogeneous isotope composition (MOMO), as expected from its long ocean residence time (800 kyr).

TL;DR: In this article, the ages of the lowermost unit (251.7 9 0.4 Ma) and near-uppermost unit(251.1 9 0 3 Ma) of the Siberian flood-volcanic event were obtained for the Maymecha-Kotuy area, Russia.

TL;DR: In the field of volcanology, the ability to forecast is being advanced by new technology, such as broadband seismology, satellite observations of ground deformation and improved field spectrometers for volcanic gas studies, leading to improvements in data transmission, data analysis and modelling techniques.

TL;DR: In this article, the authors used both 230 Th and 231 Pa dating techniques as a test of age accuracy to date Huon Peninsula, Papua New Guinea and Barbados corals formed at times since the Last Interglacial Period.

TL;DR: In this article, a large, dynamic "gas hydrate capacitor" stores and releases 13 C-depleted carbon at rates linked to external conditions such as deep ocean temperature, and the same modeling extended over longer time demonstrates that variable CH4 fluxes to and from gas hydrates can partly explain other N 13 C excursions.

TL;DR: Hirschmann et al. as mentioned in this paper showed that a silica-deficient garnet pyroxenite, MIX1G, at 2.0-2.5 GPa can be produced by partial melting of a similar material if its residue contains significant garnet and lacks olivine.

TL;DR: In this article, a continuum theory of elastic strain and point charges in crystal lattices, that account for mismatch in ionic radius and ionic charge between the substituent trace ion and the lattice site on which it is accommodated, provide a very useful theoretical framework.

TL;DR: In this paper, a positive correlation between the average degree and pressure of mantle melting that reflects regional variations in mantle potential temperatures (Lau/Manus hotter than Mariana/Scotia) was found.

TL;DR: In this article, the authors investigated the Middle Permian Maokou Formation that immediately underlies the Emeishan flood basalts in southwest China and found that the results suggest a domal crustal thinning before the emplacement of the EMEishan large igneous province.

TL;DR: In this paper, a high-resolution composite proxy record for the Indian Ocean summer monsoon spanning around 12,000 years based on the δ13C time series of both a single plant species (Carex mulieensis) remains cellulose and the total plant assemblage cellulose in the Hongyuan peat bog from the Tibet Plateau was presented.

TL;DR: In this paper, the authors used a visco-elastoplastic model to show that a fracture zone could be converted into a self-sustaining subduction zone after approximately 100 km of convergence.

TL;DR: In this paper, a comprehensive understanding of lithium-isotope fractionation during terrestrial weathering is needed in order to use lithium isotopes to trace chemical cycles, climatic changes and igneous processes.

TL;DR: In the oceans, the effective elastic thickness of the lithosphere, Te, is the range 2-50 km and is determined mainly by plate and load age, whereas the continents, in contrast, are characterised by Te values of up to 80 km and greater as mentioned in this paper.

TL;DR: In this paper, the authors use radiometrically dated Early Permian volcanic rocks from parts of Adria that are tectonically coherent with Africa (Gondwana), integrated with published coeval data from Gondwana and Laurasia, again only from igneous rocks, fully support a Pangea ‘B’ configuration in the early permian.

TL;DR: This article measured multiple sulfur isotope ratios for sulfide sulfur in shale and carbonate lithofacies from the Hamersley Basin, Western Australia, and found a similar positive correlation between v 33 S and N 34 S. The results were explained by a combination of massindependent fractionation (MIF) in the atmosphere and biological mass-dependent fractionation in the ocean.

TL;DR: In this paper, it was shown that high electrical conductivity is unfavorable for a dynamo in a metallic core, which may explain the lack of a detectable global magnetic field on Earth.

TL;DR: In the last decade, significant progress has been made toward understanding how plate tectonics is generated from mantle dynamics as discussed by the authors, which has led to plate-like segments separated by narrow, weak and rapidly deforming boundaries.

TL;DR: In this paper, the authors investigate the kinetics of metal-silicate equilibration in order to test this model and place new constraints on processes of core formation, and show that the time scales of chemical equilibrium are two to three orders of magnitude longer than the time of cooling and crystallization of the magma ocean.

TL;DR: In this paper, the elemental and isotopic composition of belemnite calcite were studied in Pliensbachian and Toarcian sections from the Yorkshire coast, UK, and Southern Germany, to investigate oceanographic change during an interval prior to and including the Toarcians Oceanic Anoxic Event (OAE).

TL;DR: In this article, high-pressure experiments were conducted on a basalt+calcite mixture in order to constrain the fate of carbonates carried on subducted ocean floor, showing that carbonates will most likely be removed from the slab before reaching 300 km, and are unlikely to be introduced by subduction either in the transition zone or in the lower mantle.

TL;DR: A detailed magnetostratigraphic record of subsidence in the Linxia Basin, documenting a 27 Myr long sedimentary record from the northeastern edge of the Tibetan Plateau, was provided in this paper.

TL;DR: Amato et al. as mentioned in this paper reported a Lu-Hf garnet-omphacite-whole-rock isochron age of 48.8±2.1 Ma from the Zermatt-Saas ophiolite from Lago di Cignana, Italy.

TL;DR: In this article, a range of equations and their derivation is presented, which can be applied to the respective pre-transport environment of a boulder and can be used to reconstruct the frequency and magnitude of past coastal wave hazards and for differentiating between tsunami and storm wave deposited boulder fields.