Objective:

Today's objective was to study and sample the Summerville formation in Candor Chasma. These rocks are known to have an abundance of bedded gypsum and gypsum nodules and are well exposed outcrops in cross-section along the river bed.

Operations and Data Collected:

A short stratigraphic column was measured at outcrops 1, 2 and 4; outcrop-scale and in situ photos were taken at each site.

1: UTM 12 S 0520166 4251418
About 2.5 m high of discernable outcrop, this site consisted of interbedded fluvial deposits and bedded pale green gypsum. As the gypsum erodes, it makes a white powder that is drizzled over the outcrop. Sample CC01 taken.

2: UTM 12 S 0520241 4251381
This amazing outcrop has a large pink gypsum nodule, over a meter in diameter at the base. The beds consist of interlayered gypsum, sandstone, siltstone and smaller gypsum nodules and secondary gypsum veins. Sample CC02 and CC03

3: UTM 12 S 0520296 4251170
This outcrop consists of all three types of gypsum (nodules, veins and beds) and interbedded with sandstone. It was photographed and documented.

4: UTM 12 S 0520711 4251122
This outcrop was too tall to complete a full stratigraphic column; the lower portion consists of interbedded gypsum, sandstone and green siltstone. The green siltstone, the bedded gypsum and the veined gypsum was sampled.

Discussion:

Today was a great success. All different forms of gypsum were sampled and observed in outcrop, and can now be prepared for laboratory work. This was an excellent location to use ATVs as transportation. The ATVs made the sample transportation easy and efficient back to the Hab. The mirrors attached to the driver's forearms need some rethinking.

The next geology EVA will be concentrating on further sampling and comparison with previous outcrops.