Open AccessChemical heterogeneity on Mercury's surface revealed by the MESSENGER X‐Ray Spectrometer
Author(s) -
Weider Shoshana Z.,
Nittler Larry R.,
Starr Richard D.,
McCoy Timothy J.,
StockstillCahill Karen R.,
Byrne Paul K.,
Denevi Brett W.,
Head James W.,
Solomon Sean C.
Publication year - 2012
Publication title -
journal of geophysical research: planets
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2012je004153
Subject(s) - enstatite , plagioclase , mercury (programming language) , geology , mineralogy , chondrite , feldspar , volcano , geochemistry , terrain , olivine , meteorite , astrobiology , quartz , paleontology , ecology , physics , computer science , biology , programming language
We present the analysis of 205 spatially resolved measurements of the surface composition of Mercury from MESSENGER's X‐Ray Spectrometer. The surface footprints of these measurements are categorized according to geological terrain. Northern smooth plains deposits and the plains interior to the Caloris basin differ compositionally from older terrain on Mercury. The older terrain generally has higher Mg/Si, S/Si, and Ca/Si ratios, and a lower Al/Si ratio than the smooth plains. Mercury's surface mineralogy is likely dominated by high‐Mg mafic minerals (e.g., enstatite), plagioclase feldspar, and lesser amounts of Ca, Mg, and/or Fe sulfides (e.g., oldhamite). The compositional difference between the volcanic smooth plains and the older terrain reflects different abundances of these minerals and points to the crystallization of the smooth plains from a more chemically evolved magma source. High‐degree partial melts of enstatite chondrite material provide a generally good compositional and mineralogical match for much of the surface of Mercury. An exception is Fe, for which the low surface abundance on Mercury is still higher than that of melts from enstatite chondrites and may indicate an exogenous contribution from meteoroid impacts.