Opportunity is on the west rim of Endeavour Crater heading towards 'Marathon Valley', a location assumed to have abundant clay minerals slightly over a half mile (1 kilometer) to the south.

The rover is stopped at an interesting geologic unit and conducting in-situ (contact) measurements.

On Sol 3848 (Nov. 21, 2014), the rover began the investigation of a light-toned vein, first with a Microscopic Imager (MI) mosaic and then with the Alpha Particle X-ray Spectrometer (APXS) placed on the same for a multi-hour integration.

On the next sol, Opportunity offset the placement of the APXS for a second measurement. To investigate the rock matrix surrounding the vein, drivers used the Rock Abrasion Tool (RAT) on Sol 3850 (Nov. 26, 2014) to brush an exposed outcrop surface and then followed this with a MI mosaic and another APXS placement. The plan ahead is to perform a multi-sol APXS integration and extensive remote sensing before driving away after the Thanksgiving holiday.

As of Sol 3850 (Nov. 26, 2014), the rover is in good health with solar array energy production of 469 watt-hours, an atmospheric opacity (Tau) of 1.458 and a solar array dust factor of 0.651.

Total odometry is 25.6 miles (41.3 kilometers).