Oregon Field Trip 2003
July 2003
By Doug Merson

Friday morning, July 4th, we set off for Oregon for a long weekend of mineral collecting. Becky and I planned to collect to collect in the McKenzie Pass area on Saturday and then head down to Diamond Lake to meet some friends from the Northwest Micro Mineral Study Group. We had a good drive to the McKenzie Pass area via the old highway. Not sure I would take that route again. It is a very narrow and twisty road. We were not impressed by the idiots head down hill that were going too fast to stay in their lane. Had a few too many close calls. Other than that it was a very scenic drive. We arrived at our camp spot at Scot Lake about supper time. The mosquitoes were very bad. They were a side dish to our meal and we were their main course. After a short hike we decided to retreat to the back of the truck and turn in early.

Saturday we were up early and on the trail to the collecting area by 0730. It was a two hour hike to the collecting site. There was still some snow on the trail in places. Lots of bear grass was about to bloom. We had no problem locating the collecting area. In a couple of hours we had all the rock we could carry out. There was plenty of osumilite and phlogopite in the pieces we collected. We had lunch and enjoyed the view of the Three Sisters volcanoes. We headed back down the trail and then off to Diamond Lake. Along the way we passed Belknap Crater. There was lava covering a very large area. It was not an area I would want to try and cross as it was very rugged, many collapsed lava tubes. It was then on to Sisters which was a very crowed small town. It would have been fun to stop and explore it and the mineral show that was being held, but at 94 it was too hot. We arrived at Diamond Lake in late afternoon. We had made reservations for a site so we got right in and set up camp. It was off to the showers to clean up. Had a late dinner, enjoyed the sunset, and the osprey.

Sunday was a free day as our friends were not due in until late in the day. We decided to hike up the Mount Theilsen trail to where is intersected the Pacific Crest Trail. It was a two hour hike gaining 2100 vertical feet in four miles. From the high point we could see from Three Sisters volcanoes to Crater Lake. We spent an hour up there enjoying the view. We met a Pacific Power worker on his day off. We mentioned that we were going to collect at Lemolo Lake which is one of their reservoirs. I asked about an old quarry supposed to be located downstream from the dam. He confirmed it existence and said we could drive into it. We parted company and head back down. An hour and twenty minutes later we were back at the truck. Back at the campground we sat around enjoying the peace and quiet as the holiday crowd was gone. Our friend showed up about four and we had adjacent sites.

Monday morning Bill Tompkins, Don and Genie Howard, my wife and I set off for Summit Rock. This is and andesite plug dome that has been quarried for road rock. We drove to the upper part of the quarry and set out to find the target minerals. Of particular interest was volborthite and cuprorivaite. Also of interest was some excellent cristobalite. We did not find any volborthite at the top of the quarry. We are not sure about the cuprorivaite as we have to break down the rock and check every piece under the scope. We did get some cristobalite. About noon Bill left to get his wife and kids so they could go to Crater Lake. The rest of us had lunch and moved down to a bench on the east side of the plug. I showed Don what type of rock to find zircons in. While he was breaking that up I did some exploring. I located a boulder with a surface coated with chrysocolla and volborthite. Don and I managed to peel of several square inches of material. It was better material than that which he had found a year earlier. Don was the first to ID volborthite from Summit Rock. It was done by x-ray and microprobe. Other minerals we found here were ilmentite, enstatite, fluorapatite, and tridymite. Other possible minerals are pseudobrookite, magnetite, hematite, and phlogopite. Around 1600 we noticed that Crater Lake, just to the south, had vanished in a very black cloud. We packed up and head back to camp. The black cloud arrived about the time dinner was served. We ate in our vehicles as the thunder storm passed. It was not a very wet storm so with the extreme fire danger the forest service was probably not happy.

On Tuesday Bill and his family headed home. His wife and two daughters are not collectors and not really campers. The rest of us headed to Lemolo Lake. We started collecting along the spillway. We were finding lots of enstatite, some tridymite, cristobalite, pseudobrookite, and ilmenite. We were hoping to find some elusive zircon. Our hand lenses weren’t up to it so any zircon found will have to show up under the scope. It is very pale pink and will be hard to spot. My wife had the head come off her sledge hammer and disappear down a hole never to be seen again. After lunch we drove around to the lower quarry. It was quite large and will need to be explored more in the future. We found some strange crystal aggregates that have a hexagonal outline to them. They do not resemble the tridymite found here nor the cristobalite we had found earlier. Don will have them analyzed. We found some interesting vugs containing enstatite, cristobalite, and a feldspar.

We all had a very good time on this trip. There is enough material to keep us busy for many months. In the evenings we would walk around the campground and enjoy the birds and critters. There were lots of flowers in bloom and more humming birds than we could count. They were lots of fun to watch. One evening there was a commotion amongst some starlings on the ground. At ground squirrel had grabbed one and was dragging it away from the other birds. He won and started eating the bird. Another ground squirrel showed up and chased him away and left with his prize.

We headed home Wednesday morning, arriving home about 1800. After we unloaded the truck it was time to start looking at rocks. Becky seems to have made the find of the trip so far. She found a rock with a vug that has 20+ osumilite crystals in it. There is much more material to be gone over. I still have to load the photos into the computer and post some on my site at Image Event. That will probably be several more days before that happens. Tomorrow it is off early to get the llamas sheared so they will be presentable for the fair and more comfortable in the heat..

Doug Merson