Regolith studies in the last two days has concentrated on characterizing the different regolith-terrain types at both the site scale and the map scale. The preliminary legend for the units is already been modified as new landform types and regolith materials are recognized. At the site scale a particularly important aspect for mapping is the presence of cryptogamic crusts. These slow-growing communities of fungi, algae, and other microorganisms that bind the surface soil together, especially in slightly moist areas. The PIMA continues to give useful service, identifying the clay and sulphate components of soils collected from different sites.

Palaeocurrent information has been collected and forwarded to mission support as an experiment in remote analysis. Melissa has been reviewing the stratigraphy, distribution and facies of various units in the study area for a suitable topic for her Honors Thesis, and is leaning towards comparing different sections through the Cretaceous Dakota Formation.

Aeolian processes and their products is an important feature of Mars and also of the MDRS study area. These are being studied during Expedition One by Veronica Zabala at Arizona State University using data collected by the field team. Observations so far indicate that aeolian features are best developed in areas where the White Wash Member of the Morrison Formation are exposed. The relatively friable white sand appear to be the source of the aeolian deposits. On the 19th Melissa Battler and Jonathan Clarke examined an amphitheatre south of the hab that showed a range of aeolian features especially in the wash draining it. These included small sand mounds, wind ripples, deflation lags, and wind fretted surfaces. The sand mounds formed in the lee of salt bushes or large cobbles in the floor of the wash and showed a multiphase history. Some showed two episodes of deposition separated by erosion; others had tails of wind fretted alluvial sands overlain by a tail of aeolian sand. There were two different classes of ripples, small ripples of medium sand and large ripples of coarse sand. Wind erosion had resulted in scoured and fretted surfaces of alluvial sediment or exposed Salt Wash Member. These were variably mantled by lags of small pebbles. Some lag pebbles had small sand tails behind them, where the pebble density was high in effect the sand tails formed a continuous veneer including small ripples of medium sand, large ripples of coarse sand. The day was calm, but on Sunday the area experienced blowing sand and dust, we hope to capture these phenomena at the next opportunity.

Igneous rocks from the area are being studied during Expedition One by Stacy Sklar at Northern Arizona University using data collected by the field team. So far no in situ igneous rocks have been located, however the high level study area contain a wide range of igneous rock types, including obsidian, vesicular basalt, a feldspar porphyry and a feldspar-hornblende porphyry. These gravels were probably derived from the igneous rocks to the west or south, probably during the late Cainozoic. The gravels have been dissected by later erosion and now occur as relative isolated, but still extensive sheets of gravel. Studying the rocks that compose these gravels allows insight into the geology of areas distant from the study area, a technique that would be useful on Mars where the boulders found in outwash channels may represent a wide range of surface lithologies from a large area.