Images Transferred Today

More images of Nomad on the ice:
Nomad's spare generator sled Nomad pulling the generator sled (and Matt Deans)
Nomad after a blizzard

More images from the ice:
Temperature experiment to study the sinking of dark rocks into the ice The Pirrit Hills Meteorite cut in the field A rock sample with thermistors to measure the temperatures facing the Sun and ice A regelation porthole with thermistors
The Pirrit Hills Meteorite Pascal Lee's petrography equipment Rock cutting in the field Another photo of rock cutting
The Inmarsat antenna used for satellite communications The radar experiment during bad weather conditions A clearer image of the radar experiment The terrible weather snowed in some tents
The Chilean camp crew A blue ice field

Finally, these images show Nomad being transported back to Chile:
Nomad in the Herc airplane Leaving Antarctica

NASA Ames / Mars Society / CMU Field Petrography Experiment Update

The thin section image shows an area approximately 2 mm long by 1.5 mm wide. The thin section was produced in the field at Patriot Hills, Antarctica, as part of the NASA Ames / Mars Society / CMU Field Petrography Experiment.

The still image shows the section in plane-polarized light. Quartz is the dominant mineral phrase. The quartz grains appear to have been stressed and disrupted. Several grains appear to have been fractured. Kinks suggestive of shearing are visible within some grains. Planar deformation features are not evident. The dark segments are part of a network of veins criss-crossing the section and apparently distributed throughout the hand sample. The veins appear to be glassy. They contain angular to subangular clasts and give the section a fluidized texture locally. Devitrification is evident in the terminal areas of some veins.

The video (WARNING: 4.6 MB) shows the same section viewed under crossed polars and almost through a full rotation of the microscope stage. The quartz grains display interference colors of relatively high order because the section is somewhat thicker than standard (> 0.03 mm). The matrix in the dark veins is optically isotropic, consistent with glass.

Preliminary Interpretation

This quartz-dominated rock has evidently experienced significant stressing and contact with a clastic melt. The melt cooled rapidly as it quenched into a glass. Partial devitrification has occurred. A general interpretation for this rock is that it was subjected to a localized, near-surface igneous event associated with relatively high mechanical stresses. Further analyses are planned on this sample in view of its interesting petrographic features.