Iron on the Surface of Mercury: From Contradiction to Convergence? (Invited)

Details Iron on the Surface of Mercury: From Contradiction to Convergence? (Invited) Iron on the Surface of Mercury: From Contradiction to Convergence? (Invited)

Dec 2009

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009agufm.p23d..08b&link_type=abstract

American Geophysical Union, Fall Meeting 2009, abstract #P23D-08

Mathematics

Logic

[5410] Planetary Sciences: Solid Surface Planets / Composition, [5464] Planetary Sciences: Solid Surface Planets / Remote Sensing, [6235] Planetary Sciences: Solar System Objects / Mercury

Scientific paper

This contribution surveys the various Earth-based and spacecraft remote-sensing methods employed to provide data for estimating the Fe content of Mercury's surface. Iron is a major element that is important for understanding planetary formation and subsequent geochemical and petrological evolution. The innermost planet has a high average density and an iron-rich core inferred to make up at least 60% of its mass, the highest fraction among the terrestrial planets. In contrast to its high bulk Fe content, the results of middle-ultraviolet and near-infrared reflectance spectroscopy, which are sensitive to ferrous iron in silicates, suggest that Mercury's surface FeO abundance is low compared with many lunar samples. Measurements of mid-infrared emission spectroscopy, microwave opacity and extreme-ultraviolet albedo have also been interpreted to indicate surface Fe abundance on Mercury equivalent to a few wt.% FeO, similar to or lower than typical lunar highlands. For comparison, the silicate portions of Venus, Earth, Mars, and the eucrite parent body are thought to have FeO abundances of about 8, 8, 18, and 20 wt.%, respectively. However, the planet's visible albedo, color relationships among geological units, and data returned by MESSENGER's Gamma-Ray and Neutron Spectrometer are consistent with higher surface abundances of Fe on Mercury. For example, the thermal neutron absorption (which is dominated by Fe, Ti, Sm, and Gd depending on their concentrations) measured during the first two Mercury flybys is similar to that of soils from Luna 16 and 24, and is sufficiently high to require as much as 18 wt.% FeO and a few wt.% TiO2, or 11 to 21 wt.% ilmenite. Consideration of the form of Fe sensed by the various techniques can lead to partial resolution of the apparent contradictions: reflectance spectroscopy cannot unambiguously determine the amount of ferrous iron in opaque oxides, whereas neutron spectroscopy can measure Fe in any chemical state, but only if the other neutron absorbers are known to yield low absorption compared to Fe. Data to be obtained by MESSENGER from orbit about Mercury, when gamma- and X-ray spectra will have sufficient counting statistics to yield strong abundance bounds, will allow for much more accurate Fe abundance estimates.

Affiliated with

Also associated with

No associations

Rating

Iron on the Surface of Mercury: From Contradiction to Convergence? (Invited) 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 Iron on the Surface of Mercury: From Contradiction to Convergence? (Invited), we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Iron on the Surface of Mercury: From Contradiction to Convergence? (Invited) will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1769991