a Rock fragment of ALH 84001, 248. The whole size is ~1.5 cm. White squares (Crb-1,2 and Crb-3,4) indicate the locations of orange-colored carbonate patches used for our XANES measurements. A silicate grain was collected from the visibly carbonate-free area, shown by a white arrow in this image (Opx-1). Enlarged images of the carbonate patches (b) and the carbonate-free silicates (c). d The carbonate grains on a silver double-sided sticky tape. Secondary electron images of the ALH carbonate (e) and silicate (f) grains. These images were taken after the SEM-FIB processing to remove surface contaminants (see “Methods”).