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Musing about a seismic interpretation,Uinta Basin, Utah

The link below, to my online storage, containsa PowerPoint file that chronicles the process Iwent through trying to figure out the

aeromagnetic seismic interpretation of a leaseour company has in the Uinta Basin, Utah. My

web page is too primitive to present the mapsin sufficient detail to be meaningful; however,you should be able to expand the size of the

maps on the Power Point presentation. I havetentatively come to the conclusion that the

magnetic highs are more indicative of a meteorshower of small bolides rather than thetraditional interpretation that they represent

basement highs. There were too few Dakotapenetrations or sufficient seismic informationin the area at the time the map was made to

have the necessary control needed to make astructure map of this detail on the top of the

Dakota Formation. Second future drilling andwell control of tops of shallower formations

gave a different picture all together. Finally 3Dseismic did not confirm the magneticinterpretation made by the authors of this

structure map. I did not believe the authorsmade up the structural interpretation out of

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whole cloth, and the only way I could imaginethat the information necessary to map all these

small structures was obtained was by surface

mapping in the field. I made a quick drive byin the field to see if there was any surface

evidence that might indicate structural highs inthe area. I came across some large steeply

dipping sandstone blocks (megabreccia clasts?)scattered about in a small circle (seephotographs in linked file). This particular

group of clasts is off the aeromagnetic map,but in the vicinity. I also found other more

subtle evidence of small structural features.This structural information may have beenused as evidence in the field to map the small

Dakota highs plotted on the map. I might findmore of these structures that fit the mapped

structures if and when I have more time. I alsoneed to do more microscope work and try todetermine if there is any microscopic evidence

of shock metamorphism. What finding thestructure in the field did was raise mysuspicions that the magnetic highs might

represent a surface phenomena rather than a

deep basement structure. In the file linkedbelow I give more detail of how I came tobelieve that the magnetic highs were causedby magnetic meteorite material scattered on

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the surface that was measured by theaeromagnetic survey.

http://www.drivehq.com/file/df.aspx/pub

lish/timmcelvain/Uinta_Aeromag

I must emphasize that my musing about this

data is pure speculation, and at present I haveno hard evidence that these surface structuresare the result of small bolide impacts.

http://www.drivehq.com/file/df.aspx/publish/timmcelvain/Uinta_Aeromaghttp://www.drivehq.com/file/df.aspx/publish/timmcelvain/Uinta_Aeromaghttp://www.drivehq.com/file/df.aspx/publish/timmcelvain/Uinta_Aeromaghttp://www.drivehq.com/file/df.aspx/publish/timmcelvain/Uinta_Aeromag