Xenoliths, Dikes and more Pillows

Had a big day on Thursday! We started off with a quick stop at Grænvatn (minus Meagen, Adam and Michael, who had left for the U.S. :(, a small acidic lake filling some explosive craters in the Krusivik area of the Reykjanes Peninsula (see pic below). We wanted to examine the gabbroic xenoliths that were spit out during the formation of the craters, as we have found troctolite inclusions in some of our pillow quarries…

Team DC + 1 at Graenvatn examining gabbro xenoliths.

Team DC + 1 at Graenvatn examining gabbro xenoliths.

Second stop was to sample not 1 but 2 dikes that might be feeders dikes to the pillow ridges. They are well-exposed and were pretty impressive for the students to see, measure and sample…

DC/CW students measuring length and orientation of basaltic dike.

DC/CW students measuring length and orientation of basaltic dike.

Then around the corner to sample and measure trends/plunges for pillow lavas just outside of the quarries. One ridge seems to be an isolated ‘pillow flow’, while the other looks to have a collapsed lava tube. Maybe part of the ridge feeder system??

DC students measuring thickness and plunges of pillow lava, Reykjanes Peninsula, Iceland

DC students measuring thickness and plunges of pillow lava, Reykjanes Peninsula, Iceland

Finally had a long day at the quarry! We worked until 11 p.m. (but did get an excellent lamb dinner break – thanks JB!!) but measured and sampled many pillow lavas. Overall an awesome field day…

Leave a Reply

Your email address will not be published. Required fields are marked *