Rainwater Basins, Loess, and An Imaginary Younger Dryas Connection

Saturday, June 5, 2010 1:09 PM
In " YD Crater hunt (impactites?)" at
http://six.pairlist.net/pipermail/meteorite-list/2010-June/065401.html

,
E.P. Grondine wrote:

"It turns out the backtrack intercept was already mapped
- the third image at http://cosmictusk.com

. Sorry, but
this image did not show on my computer.

One hypothesied large fragment impact point in lower
Michigan is shown. There should be another one not too
far distant."

There is one major problem with the Rainwater Basins,
as they are called, being associated with a terminal
Pleistocene impact. The oval basins that are exhibited
by the modern land surface are palimpsest landforms
created by a blanket of Middle, Late, and Holocene loesses
and paleosols draped evenly over the original Rainwater
Basins, which are developed in fluvial sediments. These
sediments are at least, Illinoian in age, Marine Isotope
Stage 6, approximately 130,000 to 196,000 BP old as a
Late Illinoian Sangamon Soil is developed in them. it
would be interesting to know the stratigraphic
relationship of the Late Illinoian Sangamon Soil to
these original basins as it would further constrain
their age.

Direct studies of these basins from cores and gully walls,
reveal that the original basins are buried by undisturbed
loess, which consists of an intact sequence, from bottom
to top, of Middle Wisconsin Gilman Canyon Formation,
Late Wisconsin Peoria Loess, Brady Soil, Holocene Bignell
Loess, and other interbedded and associated paleosols
(Zanner and Kuzila 2001, Zanner et al. 2007). The fact
that the original basins are blanketed by loess of the
Gilman Canyon Formation clearly demonstrates that the
original Rainwater Basins are greater than 30,000 to 40,000
years TL and C14 (Johnson et al. 2008; Wiley 2009). It is
quite obvious that the Rainwater Basins are far too old to
be associated with any hypothetical Younger Dryas event.
The presence of an intact and undisturbed blanket of Late
Wisconsin Peoria Loess, Middle Wisconsin loess of the
Gilman Canyon Formation, and associated paleosols
covering the original Rainwater Basins makes any
association between the them and the Younger Dryas a
complete and utter physical impossibility as extraterrestrial
impacts cannot create craters tens of thousands of years
before they happen.

Go look at:

Johnson, W. C., Willey, K. L., Mason, J. A., and May, D. W.,
2007, Stratigraphy and environmental reconstruction at
the Middle Wisconsinan Gilman Canyon Formation type
locality, Buzzard's Roost, southwestern Nebraska, U.S.A.
Quaternary Research. vol. 67, pp. 474-486.
http://dx.doi.org/10.1016/j.yqres.2007.01.011

Wiley, K. L., 2009, Environmental and Pedogenic Change
in the Central Great Plains from the Middle Wisconsinan
to the Present. Unpublished PhD. dissertation, Department
of Geography, University of Kansas, Lawrence, Kansas.
http://hdl.handle.net/1808/5590

Zanner, C. W., and M. S. Kuzila, 2001, Nebraska's Carolina
bays. Geological Society of America Abstracts with Programs,
v. 33, no. 6, pp. 438.

Zanner, C. W., W. Dort, Jr., and S. R. Bozarth, 2007,
Holocene Bognell Loess Chronology. Stratigraphy and
paleoenvironemntal reconstructions from within a loess
table, Southwestern, Nebraska. Geological Society of
America Abstracts with Programs, v. 39, no. 3, pp. 73.

Yours,

Paul H.