Geochemical modeling of the Martian mantle reservoir: Upwelling plume origin for SNC meteorites

Details Geochemical modeling of the Martian mantle reservoir: Upwelling plume origin for SNC meteorites Geochemical modeling of the Martian mantle reservoir: Upwelling plume origin for SNC meteorites

Dec 2003

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2003agufm.p12b1066s&link_type=abstract

American Geophysical Union, Fall Meeting 2003, abstract #P12B-1066

Physics

1060 Planetary Geochemistry (5405, 5410, 5704, 5709, 6005, 6008), 5455 Origin And Evolution, 5480 Volcanism (8450), 6225 Mars

Scientific paper

SNC meteorites (shergottites, nakhlites and chassignite) are widely accepted as their origin from Mars. Although individual SNC meteorites have been studied intensively to understand their petrogenesis, a question of how the parental magma was generated in Martian mantle has never been answered. Considering the absence of plate tectonics in Martian mantle, upwelling plume could be the only way to generate magma in Martian mantle. In addition, SNC meteorites have initial 143Nd/144Nd and 87Sr/86Sr ratios of which range is wider than all terrestrial basalts. Their strongly depleted and enriched isotopic compositions suggest the existence of terrestrial-mantle like depleted reservoir and crust-like enriched reservoir in Mars. In this study, we propose a new geochemical model involving upwelling plume from the deep Martian mantle, based on the results of high-pressure experiments and the geochemical analyses from the literatures. Our model successfully explains the early evolution of Martian mantle reservoirs in relation to the isotopic and trace element characteristics of later generated SNC source magmas. Our model assumes basically three steps, (1) the early mantle differentiation by magma ocean (~4.5Ga) to produce the deep mantle reservoir, (2) the first stage melting of a plume to produce nakhlites magma (~1.3Ga), and (3) the second stage melting of the same plume to produce shergottites magma (<600Ma). We examine plausible physical and chemical conditions (pressure, temperature, mineral assemblages and melting degree) at each step to estimate rare earth element (REE) compositions of magmas. These estimated REE compositions are well agreement with the parental magma compositions of nakhlites and shergottites which are estimated from the pyroxene core compositions. For the further examination of this model, initial 143Nd/144Nd and 87Sr/86Sr ratios of the nakhlite and shergottite are calculated with our model assuming the bulk-silicate Mars initial 143Nd/144Nd and 87Sr/86Sr ratios equal to 0.506726 (CHUR at 4.53 Ga) and 0.698840 (ADOR), respectively. The calculated isotopic compositions are in accordance with measured SNC initial isotopic compositions. It is therefore concluded that the majorite fractionation during the early differentiation of Mars would play a key role to produce mantle reservoir in deep Martian mantle and that the two-stage melting of single plume from the lowermost mantle can produced SNC magmas.

Affiliated with

Also associated with

No associations

Rating

Geochemical modeling of the Martian mantle reservoir: Upwelling plume origin for SNC meteorites does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Geochemical modeling of the Martian mantle reservoir: Upwelling plume origin for SNC meteorites, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Geochemical modeling of the Martian mantle reservoir: Upwelling plume origin for SNC meteorites will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1424999