Day 3
July 10
Locations: Meyers Canyon to the Narrows, Painted Hills, Hudspeth
Mudstone
Our trip today had Dr. Brennan Van Alderwerelt as our tour guide
from the University of Oregon. His undergrad years were at University of
California in Davis where he graduated in 2010 with a degree in Astrophysics and
later received his Doctorate in Geoscience with a focus on Geology/Petrology in
2012 with the University of Iowa. He has been doing work for 10 years and his
interest in geology and the environment began when he worked for the Department
of Water and witnessed just how poorly water is treated.
Where we began was South of Meyers Canyon and due to the number of fossils found in the area it is believed to be where dogs originated from. The only dinosaur fossil that has been found in Oregon was in this area. There is sediment from the Cretaceous period at this site but the further we went into the area the time stamps differ; those being the Permian, Tertiary, and Cretaceous. At this location we were able to see Picture Gorge which has basalt. As of now, there are 14 identified lava flow chambers which would have formed approximately 15 million years ago. We also learned about the K/T unconformity present in the location where approximately 43 million years of sediment layers that should be present are missing. There is also an age constraint where there is no folding in the last 16 million years. This location is thought to have been a delta because we have fine course rocks near conglomerates. Marine sediment found in this area is before dinosaur time and other sedimentary rocks tell us about the history. Some of the rocks we were able to identify at this location were: Calcite, Quartz, Olivine, Basalt and Opal. The basalt found is Clarno and is from the Tertiary period, one of the theories Dr. Brennan told us it may have been a rough draft of the Cascade Mountains. Further down the Canyon we saw a thick layer of volcanic ash from Mt. Mazama which created Crater Lake. What happened to the area was that the mountain had tried to erupt but it collapsed in itself (Caldera). This happened 7,500 years ago.
At the Painted Hills we saw many different colors of soil in the area: red (Kaolinite), yellow (Smectite), lavender (Clarno formation, Rhyolitic lava flow) and black (Manganese). More specifically it is Paleosol which is inactive soil that is clay-like material that picks up color. Kaolinite was formed during a warm wet period and the surrounding environment would have had swamps and experience 31-53 inches of rain annually. Smectite during a cooler and drier climate where there would have been hardwood forests and approximately 23-47 inches of rainfall. The types of trees that would have been present at the time are: Aspen, Birch, Walnut, Apple, Maple, Conifers and Redwood. One of the signs along the trail gave some interesting information, “Volcanic ash along with organic debris from nearby hardwood forests washed into swampy basins forming water-logged soils 33 million years ago.”
Hudspeth Mudstone was a lot of hands on. We spent most of our time digging around trying to locate fossils and see what interesting things we could find. I managed to find an interesting rock with lots of striations throughout. The mudstone chips are from having the edge of a marine shelf. We found limestone here and were told Ammonites and Pelecypod fossils could be found as well. We also stopped at a rest stop before going to the Painted Hills and learned a new word. X̄nun, which is a type of berry, the ones we found were red and orange (very tasty!).
Photographed: X̄nun berry tree
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