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Visualization of the Proposed Crater
Dec 7, 2009 3:01 PM
Posted in group:
This initial post has been edited to reflect the current status of the hypothesis.
For many decades, maps have been drawn which attempt to identify the source of the Carolina bays by using the inferred long-axis orientation of the various bays as an arrival bearing. Drawn of "flat" maps, those attempts failed to account for the fact that the flight path of any meteor, shock wave or ejecta product would not show up on a projected map as a straight line, but rather be a curve following a great circle route. Hill previously posted the classic map from the Eyton & Parkhurst paper in the associated thread HERE.
Google Earth allows for the creation of true great circle lines using the "Add>Path", or by programmatic creation of the appropriate kml. A quick test of paths drawn back from numerous Carolina bays confirms the general trend to the north-west. Using the measured alignments of an initial 40 Carolina bay fields, we generated great circle paths for visualization in Google Earth. This yielded a fuzzy triangulation locus centered at 43.5 N, 89.5 W. Our analysis implies that a great circle triangulation would yield an erroneous “surrogate” impact location, offset to the west. A flight-time adjustment of the crater eastward along the 43.5º N Parallel (taking into account the Earth rotating .25 degrees of arc every clock minute) directs us towards the actual impact site (discussed in more detail in HERE ). We heuristically examined various geological depression found along that transit, and selected the Saginaw area of Michigan’s Lower Peninsula (Lower Peninsula) for further analysis.
Why oval? Craters are circular, right??? Elliptical craters with "butterfly" ejecta patterns make up roughly 5% of the total crater population of terresterial planets and moons. They are caused by impactors which hit the surface at oblique, or very shallow angles, such as this one from Mars:
Image Credit: NASA / JPL / ASU / mosaic by Emily Lakdawalla
A vitally important detail of this lateral ejecta pattern is how well it fits into our proposed distribution of ejecta, both eastward and westward. This topic is discussed in more detail on our web page Oblique Impact. Here is how the Mars oblique impact crater looks when superimposed on our suggested impact site:
You can view a Google Earth mashup of this crater and our proposed triangulation from the Carolina bay orientations using the attached KMZ file.
One of our premisses is that the area was covered 40,000 years ago by a 1-2km thick sheet of ice from the last glacial period. Thus, any crater would be cut more from the ice sheet than from the lake basin, as it is less than 500 meters deep - rather shallow as craters go, even oblique ones. Here is a graphic created to explain the strata which the crater was cut into. Vertical scale is greatly exaggerated!
In our next post, we will provide an "INDEX" kml that shows the 30-some Carolina bay sites with links for retrieving more detailed kml for each individual ejecta field, one at a time.
Best wishes, Michael
_________________________ Men occasionally stumble over the truth ... but most of them pick themselves up and hurry off as if nothing had happened. ...... Winston Churchill