A. K. Baird

TL;DR: Elemental analyses of fines in the Martian regolith at two widely separated landing sites, Chryse Planitia and Utopia Planitia, produced remarkably similar results.

TL;DR: In this paper, the X ray fluorescence spectrometers of the Viking lander were used to determine absolute elemental concentrations of the Martian regolith, which required gain drift adjustments, subtraction of background components and use of a mathematical response model with adjustable parameters set by prelaunch measurements on selected rock standards.

TL;DR: The mafic nature of the present martian fines (distributed globally) and their probable source rocks seems to preclude large-scale planetary differentiation of a terrestrial nature as discussed by the authors, and a mineralogic model, derived from computer mixing studies and laboratory analog preparations, suggests that Mars fines could be an intimate mixture of about 80 percent iron-rich clay, about 10 percent magnesium sulfate (kieserite?), about 5 percent carbonate (calcite), and about five percent iron oxides (hematite, magnetite, maghemite, goethite?).

TL;DR: Several models have been proposed to explain the abundance of sulfur and chlorine-containing compounds in the Martian fine as mentioned in this paper, including remnant primitive lithosphere, a primitive component in the regolith, and trapping of volcanic gases.

TL;DR: The composition of the silicate portion of Martian regolith fines indicates derivation of the fines from mafic to ultramafic rocks, probably rich in pyroxene as mentioned in this paper.