7-29-2010: New (uprighted) video loaded on "Nitty Gritty" :)

Sunday, August 1, 2010

That's Hard Core!

Early this morning (~0530), our first core section arrived on deck (on the left). We core in 10 meter sections at a time and at a drilling rate of ~2.5-3m/hour, we're getting new sections every ~4 hours or so. Really exciting stuff! The cores don't look like much but to a petrologist or a microbiologist, they're the second most beautiful thing we've seen all cruise (second only to the unexpected pebbles of upper oceanic crust we got awhile ago.)

The bummer about coring out here in the crust is that our recovery is iffy, meaning that we could run the drill core down 10 meters but only recover one meter's worth of rock. Other times, we will recover closer to 8 or 9 meters. This is because the material down there can get chewed up and washed away during coring. We never know what we're going to get but any pieces are good pieces to us! :)

When choosing our samples for microbiology, we are looking for surfaces on the rock that are likely to host bugs. (Go figure, huh?) Such surfaces are those that have been in contact with seawater long enough to alter. (Explanation: Where the ocean crust meets seawater, be it at the surface or along cracks, there are chemical reactions that alter the rock to secondary minerals. Such reactions are expected to be microbially mediated therefore, where there's alteration, there should be bugs!) Our first sample (on the right) turned out to be a bust though. Although it had some pretty cool alteration going on (see the black and brownish tinge at the top right of the sample?), it proved too hard to subsample. We use a rock smashing box and chisels (all sterilized, of course) to chop up our rocks into small enough pieces for our analyses. After creating sparks trying to break this piece though we decided to abandon our efforts and return the piece back to the petrologists. It was too hard core for us!

The next sample I was awake for (the second core came up while I was getting my 3 hours of sleep for the night) was MUCH nicer! Within 5 minutes of chiseling and hammering, we were able to get enough sample for DNA and microscopy samples and still have some left over. Of course, it always helps if the sample has a thick alteration rind. :)

Several more hours of coring to go! Then the loggers put their instruments in the borehole and take all sorts of measurements of the lithology (layers of rock in the crust) with depth.

It's only the 22nd day on site, so we're making excellent progress (knock on wood). If all goes well, we'll get to visit a site of MUCH interest to us and get some VERY desireable cores. We'll see though. We still have to CORK these holes first before we start counting chickens.

Stay tuned!

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