Wednesday, August 21, 2013

Van Keulenhamna

Friday, July 26  -- Van Keulenhamna.  We literally took a westerly skip over the fjord to get to this place.

Today, Svalbard graced us with one of her gorgeous sunny ... well, it's always day.  I will go with sunny 12 hour window.

So.  Van Keulenhamna.  Here's a view looking back at the Stalbas:

First thing to notice (I will get to the awesome fold tucked away in the mountains later...).  The beach is mainly gravel, and this is clearly visible.  The beach is also not flat -- there are many little (seriously little) ridges and valleys cutting across it.  And this raised beach goes on for quite a ways...

(Person for scale, above)

We're in marine terrace territory now.  No sections today.  Today, we level the raised beaches, and we use a theodolite to do it.

This surveying technique creates a very precise vertical profile across the entire terrace.  We began the survey at the high tide mark -- an easily recognizable starting point.  The person peering through the theodolite (in this case, Krzysztof) sights the several meter high stick through the lens.  The height is recorded, in some cases to the centimeter, and the surveying continues until the sighter can no longer see the stick.  This is an image of the front-sighting technique.  It's nice and literal -- backsighting occurs when the theodolite is ahead of the stick, and turns around to face it.  Here is what you see:

We operated the theodolite in shifts -- first Group 3, then Group 1, and Group 2 took the last profiles.  I was super jealous of them, because they went all the way to the marine limit.  And then they got this amazing picture:

They're really high up.  The only rocks I climbed today weren't strictly speaking within my working duties.  But rocks sometimes call to be climbed upon, because you can see great things like this!

Now you can play your own game of Spot the Ectoproct, Coral, and Brachiopod fragment.

The theodolite was not the only goal of today's field work, however.  We also got to play detective!

Here we employ our finest CSI techniques as we search for pumice.  Happily, pumice is a very distinctive volcanic rock.  It's texture is highly vesicular, it's density much lower than the gravel on the beach, and we were looking for pumice in a pitch black shade.

Iceland pumice.  We expect that this pumice was transported via ocean to Svalbard.  There are volcanoes on Svalbard, and some of them active as recent as the Quaternary, but these are primarily in northwestern Spitsbergen (Sverrefjellet is a good example).  Not exactly close enough to spit pyroclastic material directly onto this beach, but you never know.  To ensure that this pumice is related to Icelandic eruptions, the petrology of each sample will need to be examined and compared to samples recovered in Iceland.

We also looked for intact shells in proximity to the pumice.  This was a largely unsuccessful venture, but it did afford us many opportunities to use random objects as digging tools, locate cool looking rocks, and take the occasional cowboy nap.

The view was truly spectacular.

This nearly vertical strata houses a rock glacier in the center.

 This is just awesome.

And one jump shot of me and Ingunn to end the day.

No comments:

Post a Comment