FIG. 3.

Nodular opaline silica with digitate structures. (A) An example known as Milltown-Malbay shows some of the characteristics of the opaline silica outcrops adjacent to Home Plate (see Fig. 2 for context) in this Pancam approximate true color image (sol 778, P2388), which spans ∼1 m at its base. Halley class buff-colored platy bedrock is present at the bottom of the scene (above the rover hardware). (B) An example of opaline silica sinter deposited in an active discharge channel of a hot spring at Tuja, Chile with similar characteristics. Scene spans ∼1 m at its base.