One step to Earth
Article Abstract:
Models for Earth accretion examine whether the Earth formed homogeneously, or through a complex heterogeneous process. Homogeneous accretion is being reconsidered as a viable alternative through new experiments involving the partitioning of iron-loving (siderophile) elements, which give important clues to the early history of Earth. Highly siderophile elements (HSE) occur in similar porportions in the mantle as in primitive Solar-System material. A study shows that homogeneous accretion can account for the HSE, although chondritic relative proportions place tight restrictions on homogeneous accretion.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1997
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Silicate regulation of new production in the equatorial Pacific upwelling
Article Abstract:
Eastern equatorial Pacific Ocean surface waters appear have apparently high plant-nutrient concentrations, but are low in phytoplankton biomass and productivity.It is thought that the high-nitrate, low-chlorophyll (HNLC) phenomenon is due to growth being limited by iron availability. The HNLC condition for the upwelling zone of the ocean region has been studied using field data and a silicon-cycle model, which predicts values of new and export production. These are in balance for biogenic silica, although new production exceeds export for nitrogen.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1998
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Seismic and geochemical evidence for large-scale mantle upwelling beneath the eastern Atlantic and western and central Europe
Article Abstract:
Isotope geochemistry, seismic tomography and regional geology research of volcanic rocks provide evidence for the presence of an extensive upwelling of the earth's mantle in the shape of an inclined sheet in the eastern Atlantic, which then bends toward northern Africa, the western Mediterranean and central Europe. This sheet-like upwelling is proposed to be the major cause for the volcanic activity in this region, as suggested by the presence of low S-wave velocity anomaly between the eastern Atlantic and the western Mediterranean.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1995
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