ABSTRACT OF THE TONKO LINEAMENT DISCOVERY AND SPATIAL RELATIONSHIP TO THE GUNNISON IMPACT CRATER STRUCTURE

 

Data collected during impacts from the comet Shoemaker-Levy 9 into Jupiter prompted further research into an established crater chain on Earth.  That effort now supports an extension to the 38th parallel structures.  The alignment, first identified by Johnny F. Tonko, of Alamo (Warme 2000), Gunnison (Tonko 2006), Haswell Hole (Gray 1997) and the 38th Parallel Structures Weaubleau-Osceola , Decaturville, Hazelgreen, Crooked Creek, Avon and Hicks Dome, supports an extension of the serial impact structure set.  The original series of depressions and deformation structures was approximately 700 kilometers following the 38th Parallel through Kansas, Missouri and Illinois (Rampino and Volk 1996).  The Tonko Lineament extension more than triples the previous length to a total distance of 2367 kilometers, through Colorado, Utah and into Nevada.

 

In addition, a previously unrecognized impact crater, the Gunnison Crater, fits well into this alignment.  The Gunnison Crater impact structure is 8.4 kilometers in diameter and is near the city of Gunnison, Colorado at LAT 38.48188 LON -106.98386.  Gunnison Crater, first identified and confirmed the author, supports hypervelocity impact origins by evidence of tektite and impact breccias recovered from the structure.

 

Precambrian granitic rocks of the 1700 M. Y. age group are prominent in the crater rim remnants and crater basement.  Fragments of suspected pre-Pennsylvanian rock can be found in the breccias.  Preliminary age estimation is of late Devonian for the creation of the Gunnison Crater.  This preliminary dating fits within the age constraints bracketed by the Silurian and Pennsylvanian ages of other proven, probable and suspected craters along the lineament.  Given erosion of the crater, the age and inclusion into the lineament is plausible.

 

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Additional evidence supporting meteorite impact was found by documenting fossil records of a great fish kill associated with the Gunnison Crater.  Numerous ancient fish fragments were discovered in a late Devonian formation, several crater diameters away from the impact, in a clastic wave run-up deposit.

The deposit contains disarticulated scales, plates and fins, from at least two late Devonian fish species (Bryant and Johnson 1936, Pampe 1969).  There is strong evidence of high energy water and sediment movements in this clastic unit being caused by wave motions generated during impact.  Formations older and younger than this Frasnian age layer do not exhibit such a violent emplacement.

 

TONKO LINEAMENT IMPACT CRATER RESEARCH