Processed to 3725 feet, drilled to 3754 feet

Today we boxed rock core to a depth of 3725 ft, 51.5 ft deeper than yesterday.  After the bit change, the drill crew has encountered a number of minor problems that have slowed down the drilling penetration rate.  In addition, some of the flows and intrusions are just more dense and take a little longer to cut through.  Overall, we're still making great progress.  A bit more core was delivered this evening, indicating that the drilling has advanced to at least 3754 ft below the surface. 

Here's a photo showing some interesting features we saw today:

The dark rock on the upper right is an intrusion.  Drilling only sampled the edge of it, but this intrusion appears to have baked the surrounding rock significantly.  All the olivine in the rock around the intrusion has been baked to black (click on the photo to see in greater detail).  In addition, there is a greenish clay(?) material that is partially filling the large, irregular vesicle located to the lower left of the intrusion.  This combination of features is just one of the many surprises we're seeing as the drilling continues to advance downward into the unknown.