So after a week around Mt. Boothby spent mostly in the rain, we headed for Ormiston Gorge in the western MacDonnell Ranges. After making a stop in Alice Springs to get another week of food supplies and grab some lunch from Bar Doppio's (best cafe in Alice), we drove west, fervently hoping for dry weather. When we arrived at the camping area, we found ourselves setting up in the rain. Ah well.The next morning, we awoke to find the rain gone. Fantastic -- dry field work is always better than being sopping wet. We immediately forgot about the rain. And it wasn't hard, for the geology at Ormiston is excellent. There are only four map units (including the basement), which allows the students to focus on the structure. The structure at Ormiston is textbook thin-skinned fold-thrust belt stuff -- folds, duplexes, thrust sheets. Except that there is a big thrust fault that puts basement on top of Neoproterozoic sedimentary rocks.
We spent our first day in the field getting the students acquainted with the stratigraphy and looking at the lovely structures. In order to do this, we had to wade across the Ormiston River. No problem. We headed across at about 11 AM and kept doing what we were doing. We didn't think much about it until we were on our way to cross back that we discovered that all of that water that had fallen had made its way downstream and the river had risen considerably. The place that the trail crosses the river was a rushing torrent--certainly not a place I was sending uni students. After some scouting around, we found a wide and relatively shallow (waist-high) part of the river and were able to cross. No problem.
However, the river was running across the road and had risen high enough that the buses could not get out of Ormiston Gorge and back to the campsite. As nightfall approached, we were stuck with eighty wet, hungry uni students and couldn't go anywhere. Solution? Send the intrepid Martin Hand across the river-blocked road and back to camp, where he picked up the moving truck (think a U-Haul) that we had used to ferry gear up from Adelaide. We took groups students across the water, loaded them into the back of the truck illegal-immigrant style, and drove them back to camp at 30 km per hour. We even had dinner at midnight when we finally got the last of the students safely back. All's well that ends well, right?
Happily, there was no more rain and the rest of the week at Ormiston Gorge was sunny and fine. The structural geology was really excellent, and we spent two days walking back and forth over Mt. Ormiston with students near the end of the week. A great way to end a great two weeks of field camp.
