Checking out the Big Orange Mountain

Wednesday, November 26 - Field Day 1

Woke up today at 7:50am and ate breakfast at 8 am. Saddled up the field gear and the food for the car and were off. We drove about an hour to get to the road up the mountain, then drove on up. This part was a little scary for me, because i was on the right side next to the sheer cliff. Now im not terribly bad with heights, but If youre window seat going 60 km/h on a road that has a 1000 foot drop, no guard rail, and about 2 feet of shoulder? (I certainly) get a little nervous.

Our driver Arestides is very friendly, fun, and puts up with our intermediate spanish. We finally get to the salt flat (after some extreme S curves followed by extremely straight road) and our first location: the Limestone Outcrop. Now we didnt know this was a limestone outcrop (formerly big orange mountain) until we climbed it (whew) and smashed a rock and put acid on. It fizzed, which lead us to conclude it was limestone. Ingrid filled us in about the 'deal' with this area and what we were looking to find, and I was taught how to calculate the strike and dip of strata. After further examination we concluded that the overall mountain was a form of micrite (mud layers and limestone layers I believe) so I grabbed some samples of those two beds. We climbed down and located where the igneous rock intersects with the limestone on the west side, and again on the east side, and also found some faults going through the limestone bed. This poor outcrop was getting 'sheared to shreds' basically.


Afterwards we went South to the Igneous area and tried to identify the strike and dip of that strata, and locate where the clastic material intersects the basaltic lava material. We seemed to get a pretty good idea and drew that outline on our map. Took down some GPS points as well as strike/dip measurements and should be able to get a better understanding of the area.

Finally we got a ride all the way up to the huge fault scarp to the west (extremely visible on the map). It is also the windiest place I have ever been in my life. Lots of 'first in my life' experiences with this trip, its very exciting. Ingrid told us about the area, the fault, the spherules, previous expeditions to the area and what they were aiming to get out of the fault scarp (possible terraces?). Now we have a good overview of what to work on (and look for!) with the spherules and how to tackle the fault scarp in the future. We got back in the truck and zigged and zagged boulders on the way down to the main road. It was then that I understood the significance of a high bedded truck for our trip: to drive over the foot large boulders! In all I'd say that was a pretty good first ever field day for me. I'm looking forward to the rest!