A VERY GOOD PLACE TO START!
Welcome to anyone who wishes to learn more about the historic Geology of north-central Oregon! I present this to you after 40 years investigating the field geology of the Mitchell region with the help of professional colleagues and my many students. Why should anyone persist in climbing on about 150 square miles of these semiarid hills for so long? It was my way of teaching more than 600 prospective geologists how to observe and interpret rocks and landscape while they earned degrees at Oregon State University. While they prepared maps and notes, I did the same and preserved my maps for use in succeeding summer sessions. Now that I am very retired and in my ninth decade, I have taught myself enough HTML-CSS computer code to construct this website and to offer my maps and my conclusions to others. It is my opinion that the area near Mitchell provides one of the few places to learn what ancient central Oregon was like before it was covered by the many layers of Late-Tertiary volcanic rock that we see today.
Consequently, you will find here a set of the most detailed geologic maps that have been made available for any part of Oregon. Full-color quarters of many 7.5–minute maps are presented with complete legends and the options of scale enlargement and scanning. Please note that most browsers like the one on your computer display click-options or keyboard instructions to control size of images. When they are applied without reverse action, the result may continue onto subsequent images of maps, photos, and text. Best to regain original size before moving on to another feature.
You will also find a chronological listing of major geological formations followed by a sequential description of central Oregon geologic events. Detailed interpretations of the conditions of origin and deformation of each formation are also presented, in many examples here for the first time. For those who need more details, complete listings are given for radiometric ages, chemical analyses, and previous authors. At each step, you will find a link to the main menu that provides access to all of the above.
In addition to the large compilation of published works listed in the references, and the many authors who visited and assisted the OSU Summer Geology Program, I wish to acknowledge the professors of geology that I closely worked with for so many years: W. D. Wilkinson, K. F. Oles, H. E. Enlows, R. Lawrence, A. L. Neim, J. H. Dilles, and R. S. Yeats.
If you are not familiar with landscape names and locations used in these discussions, the following illustration may be of assistance:
W. D. Wilkinson joined the Oregon State University Department of Geology at its inception in 1932 where he taught mineralogy and served as chairman from 1960 until 1968. He initiated and sustained the O.S.U. Geology Summer Field Program for 25 years. “Doc” Wilkinson was not a passive individual. He became a forceful presence in the lives of his students, confronting them width a rough exterior or an understanding heart, as the occasion demanded. His conversations were punctuated occasionally with swear words for emphasis, but his office was always open to students for coffee and discussions of problems both personal and geologic. There are many talented people who would never have become geologists if Doc had not set aside his private ambitions and devoted his efforts to their development. His professional specialty was in guiding young people toward highly successful careers and rewarding lives. His skill will be long remembered.