Time: approximately 2:30pm to 4:30pm

General direction: SSE of the HAB

Distance: Approximately 2.5 miles

Goals: general reconnaissance of the geology, collect rock samples, collect biological samples

Narrative: Initially we had planned on conducting a long EVA today by returning to the Barsoom Outcrops for a more detailed analysis of this geologically and biologically rich site. However, because of today’s crew changeover (Robert Zubrin and Frank Schubert departed and Andy De Wet and Tony Muscatello arrived to join Jen Heldmann, Troy Wegman, Heather Schluda, and Steve McDaniel), various Hab maintenance activities caused a late start for the EVA. Therefore, the crew decided to conduct a shorter reconnaissance EVA towards the south of the Hab, an area that to date had not been explored by an MDRS EVA. Therefore Jennifer, Heather, and Andy set out on the ATVs and marked observation waypoints as well as conducted more detailed studies of several of the sites. Findings are described below.

Waypoint 48: 4249.79 km N, 518.20 km E, Observation Point - Elevation: 4498 km.
Quick stop on the road from the HAB to Route 24 West. Here the road crosses a broad flat valley. The ground is covered in small pebbles comprising a wide variety of rock types. A small gully crosses the road here. The gully bed comprises sand with few pebbles or boulders. From this vantage point, the top of the HAB ridge could be observed. A resistant layer several meters thick defines the ridge. A 10 to 20 meter thick less resistant (Clay?) gray layer occurs below the ridge. Below this occurs a thick (50 to 100 meters) sequence of alternating red and white layers. Observation images facing north, south, east, and west were taken at this point.

Waypoint 49: 4248.75 km N, 519.09 km E, Low Stratigraphic point – Elevation: 4482 ft.
Broad flat plain to the west and small irregular gullies and hills to the east. The gullies cut through a sequence of medium to coarse grained cross-bedded sandstones and conglomerates. This outcrop is clearly stratigraphically below the sediments described at waypoint 48. The cross-bedding occurs in set between 20 cm and several meters thick. The clasts include a wide variety of lithotypes and minerals. The grains are well rounded but poorly sorted indicating a somewhat proximal source. The cross bedding indicates a fluvial environment. Geo Sample 49.1 of the conglomerate rock was taken here. Bio Sample 49.1 was an endolithic organism in a conglomerate rock. This site was digitally imaged.

Waypoint 50: 4249.01 km N, 519.19 km E, - Higher Stratigraphic point - Elevation: 4482 ft.
This was a small hill (18 feet high) that included red medium grained cross-bedded sandstones with a few thin discontinuous conglomeratic horizons. These rocks appeared to be stratigraphically above the rocks described at Waypoint 49. They may represent a transitional sequence between the thick cross-bedded sandstones and conglomerates below and the finer grained red and gray layers above. Geo Sample 50.1 of the red sandstone was taken here A biological sample 50.1 was an endolithic organism near the surface of a sandstone rock.

Waypoint 51: 4247.49 km N, 520.25 km E, Top of Canyon – Elevation: 4404 ft.
This stop was located between the road and a small canyon to the east. Numerous large pebbles and boulders were strewn across the landscape. The boulders seem to be concentrated in certain horizons although the boulders were not found insitu. The boulders were covered in black desert varnish but they included a wide variety of resistant lithologies including igneous rocks (diorite?), coarse-grained quartzites and chert. The boulders are all well rounded and flatten. They may represent a beach deposit because finer grained sandstones with bioturbation (feeding traces of worms?) were identified in this sequence. The bioturbation probably occurred in a shallow marine environment.

One biological sample was taken here; 51.1 was another endolithic organism found when breaking open a layer of sandstone. Geologic samples of the igneous rocks were also collected. This site was digitally imaged.

Waypoint 52: 4247.52 km N, 520.38 km E, Bottom of Canyon – Elevation: 4374 ft.
This waypoint was located in the small canyon to the east of Waypoint 50 (approximately 30 feet deep). A thick sequence of cross-bedded sandstones and conglomerates overlies an alternating sequence of thinner red and brown sandstones and siltstones. Fine grained gray-green horizons may represent shallow marine deposits. Thick-bedded coarse-grained cross-bedded sandstones occur in the lowest parts of the canyon. These rocks represent the lowest layers in the sequence we traversed during EVA7. The canyon contained flowing water.

Two biological samples were taken here. 52.1 was a sample of the frozen water. 52.2 was a sample of sandstone with black and pinkish-white lichen epilithic. When a layer of the rock was broken open a layer it revealed a small colony of brown-green endolithic organisms that were sampled. Geologic samples of the red and green coatings on the outcrop as well as a sandstone sample were collected. This site was digitally imaged.

A crude stratigraphic sequence can be developed based on these observations. This sequence will be improved with observations made on future EVA’s.