Fig. 1. Alkali (Na₂O + K₂O) versus SiO₂ classification diagram for volcanic rocks modified after Agee et al.

(4) and McSween et al. (19). The NWA 7533 clasts in this study (the red solid circles), whole-rock NWA 7034 meteorite in Agee et al. (4) (the green solid circle), and SNC meteorites (25, 26) (the orange field) are compared with the gamma-ray spectrometer (GRS) data of the Mars Odyssey orbiter (19, 20) and those of rocks and soils in Gusev Crater (the gray dots) from the alpha particle x-ray spectrometer (APXS) on the Spirit Rover (21, 22) and in Gale Crater (the grey crosses) from APXS (23) and laser-induced breakdown spectrometer (ChemCam) (24) on the Curiosity Rover. Note that clast C4 is plotting outside the figure due to its high alkali content (data file S1).