The beautiful Holden Crater

This HiRISE image covers a portion of the floor of Holden Crater situated in southwest Margaritifer Terra. Holden crater has likely experienced extensive modification by running water, which is supported by observations of drainage and deposition into the crater from a large channel breaching Holden's rim and the alluvial fans that built out along the floor of the crater. The HiRISE sub-image shows relatively bright finely layered deposits that are capped by relatively darker materials. Unlike previous images, the HiRISE image shows that the thickness of some of the individual layers are on the order of a meter or even less in thickness and are laterally uniform and continuous over the extent of the imaged outcrop. Some of the layers in the outcrop display an orthogonal pattern or what may be fractures or joints. The "layer-cake" appearance of these layers suggests that they may have been deposited into a lake that once occupied the crater floor and have seen little in the way of deformation since that time. By contrast, the darker materials overlying the layers are younger and may have been sediments deposited off the nearby alluvial fans. Alternatively, they may represent wind-blown deposits lain down during a later much drier period similar to the conditions that currently exist at the surface today. In some locations, the darker materials have been stripped and expose the lighter finely layered sediments underneath, thereby implying the finely layered materials extend much farther than what is visible along the large outcrop.