Laguna Hollow: a "breathing" depression? - Sol 46

Caption NASA originale:"This image shows the patch of soil at the bottom of the shallow depression dubbed Laguna Hollow where the MER Spirit will soon begin trenching. Scientists are intrigued by the clustering of small pebbles and the crack-like fine lines, which indicate a coherent surface that expands and contracts. A number of processes can cause materials to expand and contract, including cycles of heating and cooling; freezing and thawing and...rising and falling of salty liquids within a substance. This false-color image was created using the blue, green and infrared filters of the Rover's PanCam. Scientists chose this particular combination of filters to enhance the heterogeneity of the Martian soil".