Biology:

During the exploration of Hab ridge, the crew examined patches of lichen and discussed the symbiosis between fungi and algae which allows lichen to survive in extreme conditions.

The preliminary scouting of a fossilized oyster bed (WGS 84 - UTM Z12S 0517909, 4251238) resulted in a discussion on the distinction between thanatocenotic and biocenotic deposition. Biocenotic refers to a deposition that occurs while the organism is still alive, while thanatocenotic deposition is when the organisms die in another location and their bodies are carried to a new location and fossilized. Andre, the crew geologist, suggested that due to the thickened and fractured nature of the oyster fossils, they likely grew in a high energy environment and were transported to their final deposition site, indicating thanatocenotic deposition.

An Oyster Fossil

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Geology:

During the first training EVA, the general geology and stratigraphy of the Dakota Sandstones and the Morrison Shales was discussed, including the oyster beds near the upper boundary of the Dakota Sandstones (see biology report), and the concretions previously studied on Expeditions One & Beta.

Observations were made as to the nature of the contact between the two formations, noting the trough cross-bedded basal unit of the Dakota Sandstones, unconformably overlying the alternating reduced and oxidized Morrison Shales (WGS 84 - UTM Z12S 0518021 4251227). This observation indicates the depositional hiatus between the Jurassic and Cretaceous periods. The depositional environment may have changed during that time from a quiet marine setting, in which the Morrison Shales were deposited, to an energetic fluvial or aeolian environment, in which large subaqueous, or subaerial trough cross-bedded dunes were deposited.

Contact between Dakota sandstone and Morrison Formation

Concretions and minor occurrences of coal were also observed in the Dakota sandstone. These were expected from previous studies of the area, however a new, outstanding outcrop was discovered at WGS 84 - UTM Z12S 0518021 4251227 (same coordinates as unconformity mentioned above), featuring extremely well formed concretions, which look very similar to the Martian "blueberries". Most concretions were spherical, roughly 0.5 to 1 cm in diameter, and brown in colour; exactly like the concretions previously documented in Battler's thesis, and therefore likely contain calcite cement.

In addition, we discovered orange, iron-bearing concretions, (also documented in Battler's thesis, but rare around MDRS), which may contain iron oxide (possibly limonite) cement, and therefore be chemically more similar to the Martian blueberries, at WGS 84 - UTM Z12S 0517941 4251234. The locations of these concretions will be documented, and later added to a high detail map of the area (possibly by Andre during ExBeta, otherwise later as a potential RST project?).