Southern Rocky Mountain and Colorado Plateau Mid Tertiary Impact Event


 New Evidence Dating the Beaverhead Impact Crater as a K-T Boundry Event


Please be advised that I have revised and published most of these articles on my page at Scribd -




With this website I will present evidence to support my hypothesis that there was an enormous Mid-Tertiary Impact Event in the Southern Rocky Mountains and Colorado Plateau.

I have been asked by family, friends and colleagues what I have been working on for the past 10 or 11 years. The project has grown from gathering evidence to verify a small isolated impact crater to a regional event. This website is an attempt to help me put my thoughts in order, and a vehicle that may help me explain what I have been doing for the last decade. I expect to be adding and subtracting from this web page for as long as I can keep my thoughts together; however, it will be a snapshot of my progress. So I beg your indulgence as I jump off into uncharted water.

I am proposing several new impact structures along with known impact structures, and evidence of shock metamorphism in areas that I cannot associate with a specific impact structure within the Southern Rocky Mountains and Colorado Plateau. It is premature to speculate about the nature of the impacting bodies before there is any conclusive evidence that the proposed impact craters are indeed impact structures, but the assumption that there was a impacting body that caused multiple impacts and/or chain impacts helps me form a hypothesis that I can predict and test. My hypothesis speculates that all the impact structures, proposed impact structures, and evidence of shock metamorphism is coeval and is the result of the impact of an asteroid or comet composed of loosely packed bolides ranging in size from dust to very large bolides capable of creating an impact crater fifty or more kilometers in diameter. There is both macroscopic and microscopic evidence that I believe is the result of shock metamorphism and corroborate or complement the specific proposed impact structures. In conclusion I will present a working hypothesis of the history and development of this impact event. I recognize that the accepted evidence of an extraterrestrial bolide impact such as Planar Deformation Features (PDF’s), Shatter Cones and Impact Craters are the subject of widespread debate, and it must be noted that except for the Santa Fe Impact Structure, Upheaval Dome Impact Structure, and Sierra Madera Impact Structure, my identification and conclusions have not been substantiated by the experts in the field.


Hubble Telescope Image of the “String of Pearls Comet” credit: Dr. H. A. Weaver and Mr. T. E. Smith, STScI, NASA

Possible Crater formed by a Shoemaker-Levy type Impactor


My History

Tim McElvain

Bachelor of Science Geology, University of Arizona ­

I am a petroleum geologist and was part owner and President of a small family oil and gas exploration and production company for forty years.

Some thoughts on the history of my investigation

After I retired from the oil business I decided to map the geology surrounding our home near Pecos NM. The geology and the structure in that area completely confused me until serendipitously my wife and I visited Rochechouart, France and rented an apartment for a week, because we thought the town and surrounding countryside would be interesting to visit and walk through. While we were there I found a museum dedicated to the Rochechouart Impact Structure, which also had a map of walks illustrating various elements of the structure. During our stay as I visited the museum and walked the countryside a light went off in my head, I all of a sudden understood what was confusing me at home. Further investigation convinced me that our home lay within the central uplift of a morphological complex impact crater approximately 9 miles in diameter. In order to try and prove that the Pecos Structure was an impact crater I began to read about impact craters and attended field sessions and field trips on the subject. During this process I came away with the realization that the only definitive proof that a structure is the presence of shocked quartz more particularly planar deformation structures (PDFs). Shatter cones can be proof of impact but they can also be made by lesser explosions. With the assumption that one would have to find shocked quartz or shatter cones within the structure I began to examine the quartz in the sandstone within the Pecos Structure. I found planar microstructures (PMs) in the sandstone, and what I believe is a shatter cone. In order to substantiate that the PM's were shock induced I began to measure the angle of the plane of the planar microstructure to the c-axis, and then to index the results. I had very positive results, but still have not been able to convince the experts. During my field work I also found what appeared to me to be another smaller impact structure within the Pecos Structure, which intrigued me and expanded my area of interest. I began looking in the Pecos area finding evidence of shock metamorphism as I explored farther and farther afield I have ended up searching all over the Southern Rocky Mountains and Colorado Plateau.

With the one assumption that shocked quartz is the only definitive evidence of an impact crater I began to prospect for shocked quartz. The results were interesting and encouraging but confusing. At first I began to look for shock metamorphism in the center of likely structures, but it soon became apparent that I was more likely to find the shocked quartz in the youngest and highest structural beds affected by the structure even if they were towards the outer ring, and especially if the rocks were allochthonous blocks of younger rocks lying between the central uplift and the outer rings. Slowly after years of field and microscope work the immensity of the Impact Event began to sink into my mind. If my hypothesis is correct the impact was caused by an extended asteroid or comet resembling the Shoemaker-Levy Comet as it impacted Jupiter. In that case the size of the individual impact structures would be fractal. The impacting object could range from very large bolides, or varying densities of material, or clusters of bolides, down to dust. Due to the countless number and fractal nature of the impacting objects the structures are very complex and difficult to identify; however, I now believe I can recognize some very large melt bodies and central uplifts even though many of the other elements have been destroyed by erosion and/or overlapping impacts. And most important I believe I have identified some distal ejecta of this giant impact event. I need to emphasize that the planar microstructures (PMs) that I have identified have not been verified as shock generated or as PDF's by the experts in the impact field. Assuming I have discovered shock metamorphism I have developed a working hypothesis which I will showcase at the conclusion of this presentation that seems to fit the results of my work. This working hypothesis is a work in progress and is subject to radical changes as my research continues.

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