Constraining the chemical depth profile of a manganese-rich surface layer in Gale crater, Mars

Geochemical analyses by X-ray spectrometry and laser-induced breakdown spectroscopy (LIBS) instruments on the surface of Mars enable detailed studies of surface materials. The two techniques are utilized in concert by rovers to glean information in a complementary fashion. However, fundamental differences in how these analytical techniques function can produce perceived discrepancies in results, such as those resulting from variation in sampling volume. Here we utilize data acquired by the APXS (X-ray spectrometer) and ChemCam (LIBS) instruments on the Curiosity rover to investigate a manganese-rich surface layer, and, in the process, provide an improved chemical depth profile. We also demonstrate a method whereby current and future spacecraft capable of utilizing both techniques can potentially improve estimates of martian material near-surface density.