05 October, 2009

Dispatches from the Field #2

Mapping complete and fighting with making a good profile

Day 5:

Today was a good day. Dispite sleeping-in late and getting lost on the road - it's really confusing to drive on these tiny French roads - I did what I wanted. The point making my day good was that I found a couple of locations with big calcite veins within 50 to 100 m of where I was expecting to find some clue for a big fault that I had been hypothesing upon the day before. Left and right side of the veins are off-set by at least a few meters. Great! There also is an old quarry that I discoverd today in which can be seen some nicely folded and layered limestone beds. The base of the formation of my interest - I think. It seems like the very old geologic map that I am basing my work on is correct in all its details. Tomorrow I will inspect the last two places of my field area. If there are no unexpected surprises here mapping will be done tomorrow and I can draw the working version of the map. Three days for 2 square km sounds pretty good. If all goes well tomorrow I might also begin with the first profile and selecting some preliminary and random samples. The only downside so far has been that the Mumienbank, a wonderful oncoid bed that would enable a rough stratigraphic positioning, seems to gone. Only some occasional float from the lower most part of the oncoid bed or the underlaying grainstones can be found here and there. To end the day with a positive expression: After taking a few dip measurements it will by a piece of cake to construct the Isoline Map! The morphology here delivers very good clues on where the hard limestones begin even when the lower contact is not exposed.

Day 6:

Today went well. Found another few spots with calcite veins just in the right location for fault lines. The morphology also screams "fault"! The entire area is mapped now and I think I found all useful outcrops as well. The evening was best, when putting everything onto the map and get confirmation that all veins, silified rock and similiar stuff is really where I suspected that it should be. Good!

Day 7:

A slow day. Wasn't really motivated. I managed to speak to the owner of the active quarry and I can come friday to pick-up the keys so I can access it on the coming weekend. I hope two days will be enough to make the profile, measure it and take enough samples. Aside of that I spent a very long time in an old quarry trying to make sense of it. The bedding is really a mess. Most of it is simply an extreme version of stylo-bedding in my opinion. I grouped these stylobeds into a "bed" when they were identical macroscopical. I got 12 beds this way in a 20m high quarry wall. Still, lazy, I hope the other places will go quicker than all day long.

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