Observations of Washington State Landscapes, Geology, Geography, Ecology, History and Land Use
Friday, June 18, 2010
Unconformity-Bounded Sequences and Colored Pencils
I have been reading a paper titled Cenozoic Unconformity-Bounded Sequences of Central and Eastern Washington by Eric Cheney. I think it is about the fifth time I have read it. The summation is that some of the major Cenozoic units in eastern and central Washington are much more extensive and covered much larger areas at the time of deposition or in the case of the Columbia River Basalts lava flows.
Cheney includes a geologic map of Washington State. The map shows superterranes and major sequences as regional units versus standard lithologic and chronological maps. It is a different way of looking at the geology of the state and clarifies relationships between units. A number of the details could be debated, but at least for this map I simply stuck with Cheney's interpretations.
The coloring is my own. I picked colors that I associated with the units. Walpapi is brown as it is mostly basalt. It is my way of learning and follows a recommendation a professor of mine, Ned Brown, to get out the crayons to learn geologic units. Preschool kids color stuff as a way to learn and it works as a great way to visualize and understand relationships. I found this approach has always helped when I am working in a new area.
Eric Cheney was also a professor of mine. I took a couple of economic geology classes from him. I remember he once told our class that while we might all be focused on gold and other metals, but gravel mining resources were very valuable and should not be dismissed as an engineering issue. I always remember that as it turns out I have done a fair number of sand and gravel and quarry rock evaluations.
Dan McShane is an engineering geologist with Stratum Group, a geology and environmental consulting company based in Bellingham, Washington. Dan has been reading Washington State landscapes since driving across the Horse Heaven Hills with his father and brother in 1970. Dan's wife has started painting Washington landscapes. The intent of this blog is to help all Washington travelers better understand the landscapes we see and share field observations.