Science Report
Feb 15, 2013
Crew 124
Purpose:
We had four stops planned of which the first two were more exploring wise, check out a gravelly alluvial fan and a clear line on the satellite that seemed like a fault plane. The second and final two stops we wanted to explore and look for endolithic samples. An inverted riverbed and a actual riverbed that appeared to be white on the aerial photos were selected for this EVA.
Narrative:
It was the first day taking the ATVs out, so we could go further away from the habitat for the first time to explore! The first stop of the day was a place where there seemed to be an alluvial fan, (based on satellite images), but at the scene it looked more like a desert paved corner in between hills. Wind that is pushed through the hills accelerates in speed and removes the dusty clays but is not able to move the gravel. The gravel on the surface had a small dry creek cutting through. Also the high rounded rolling morphology of the locations of the gravel did not conduct with the possibility of an alluvial fan. We walked up the creek, and saw some calcium/gypsum precipitation spots. We went to stop number two to seek for a possible fault plane, again interpreted from a satellite photo. We saw a large outcrop at our south east that was cut of in line of fault. We looked for more deformation structures but no actual evidence due to the soft strata could be found. We took of to the third stop, which, judging by the satellite images seemed to be an inverted river. We parked our ATVs on the side of the road and walked up to a high hill that seemed to be the elongation of the inverted riverbed. The strata consisted of sandstone and conglomerate. We saw some strange holes in the layering that looked like they were induced by secondary water-flowing processes. A picture of this is included, in case anyone knows what it actually is, please let us know. The same feature was also found at the top of the hill, all over these depositions were small and larger holes up to tens of centimeters in diameter. Ase and Tristan walked up the hill to seek for endolitic samples, they found two different ones. Then we walked 400 meters to WNW (WestNorthWest), here the inverted river bed looked like a long high stripe that lays atop of the surrounding clay deposits. Here we sought for more endoliths. We found one and took a sample of it. Also here the strange holes in the conglomerates were present.
At the next stop, a dry riverbed, we saw that the whiteness is caused by high levels of calcite/sodium of gypsum or halite precipitation. Possible from close by evaporate deposits. Some hand and drill samples were taken. We walked approximately 700 meter to the west following the riverbed up stream and crossed a clay hill with a lot of gypsum sheet crystals laying loose on the top. Here we sampled some and had a short search for desert rose crystals, but we could not find any. Approxametly 200m west we found a steep ridge of bright red clay layers with white sandstone layers that protrudes over the riverbed. The layers of more resistant sand to siltstone layers stuck out of the ridge. They had white and red colorings, non dependent on the layering of the strata. This is probably caused by ground water flows that had some parts of the sandstone oxidized, coloring it red. April drilled some samples of clay and sandstone. This was our last stop. On our drive back we observed some nice mushroom features of thin spaced red sandstone on top of white clays.
(Written by Dennis, with small additions from Åse)
coordinates of our stops:
Stop 1: Alluvial fan
Check In One E:
518787
Check In One N:
4251611
Stop 2: Possible fault
Check In East Two:
519210
Stop 3: Inverted riverbed
Check In East Three:
518763
Check In North Three:
4252172
Stop 4: White dry riverbed
Check In East Four:
518170
Check In North Four:
4253780