Understanding the signature of rock coatings in laser-induced breakdown spectroscopy data

作者：Lanza Nina L a^*; Ollila Ann M b; Cousin Agnes a; Wiens Roger C a; Clegg Samuel a; Mangold Nicolas c; Bridges Nathan d; Cooper Daniel a; Schmidt Mariek e; Berger Jeffrey f; Arvidson Raymond g; Melikechi Noureddine h; Newsom Horton E b; Tokar Robert i; Hardgrove Craig j; Mezzacappa Alissa h; Jackson Ryan S b; Clark Benton k; Forni Olivier; Maurice Sylvestre m; Nachon Marion c; Anderson Ryan B n; Blank Jennifer o; Deans Matthew p; Delapp Dorothea a

来源：Icarus, 2015, 249: 62-73.

DOI：10.1016/j.icarus.2014.05.038

• Mars, surface
• Spectroscopy
• Geological processes
• Experimental techniques

Surface compositional features on rocks such as coatings and weathering rinds provide important information about past aqueous environments and water rock interactions. The search for these features represents an important aspect of the Curiosity rover mission. With its unique ability to do fine-scale chemical depth profiling, the ChemCam laser-induced breakdown spectroscopy instrument (LIBS) onboard Curiosity can be used to both identify and analyze rock surface alteration features. In this study we analyze a terrestrial manganese-rich rock varnish coating on a basalt rock in the laboratory with the ChemCam engineering model to determine the LIBS signature of a natural rock coating. Results show that there is a systematic decrease in peak heights for elements such as Mn that are abundant in the coating but not the rock. There is significant spatial variation in the relative abundance of coating elements detected by LIBS depending on where on the rock surface sampled; this is due to the variability in thickness and spatial discontinuities in the coating. Similar trends have been identified in some martian rock targets in ChemCam data, suggesting that these rocks may have coatings or weathering rinds on their surfaces.

• 出版日期2015-3-15