In the midst of native limestone you
can find piles of pink rocks. These rocks have traveled from
southern Minnesota to visit the beautiful flint hills of Kansas.
How did they get here? The rocks, pink quartzite to be exact,
are examples of glacial erratics. During the ice age these stones
were picked up by the advancing ice sheets and carried along the
leading edge of the sheets. As the ice melted and receded the
stones and boulders were dropped off. This particular area is
unique because it is at the farthest edge of the ice flow and it
seems that the pink stones just stop. To the north of this point
you will see a line of quartzite dropped naturally. To the south
you will find very little of it.Farther north of this point you can
find pink quartzite from marble size up to the large 20 foot
diameter boulders found near the Minnesota Boundary Waters.
During the Pleistocene Epoch--past 1½ million years--several
major glacial-interglacial cycles have taken place. The most recent
glaciation is known as the Wisconsin. This glaciation began about
110,000 years ago and reached its maximum extent between 20,000 and
14,000 years ago. A complex of ice sheets covered nearly all of
Canada as well as the northern United States, and an ice lobe
reached as far south as Des Moines, Iowa.
The glaciation of northeastern Kansas and northern Missouri took
place much earlier. This glaciation is now known as the
Independence, after Independence Creek in Doniphan County, Kansas.
The Independence ice sheet existed during the interval
approximately 610,000 to 780,000 years ago. The Kansas City region
was invaded by ice at least two times during the Independence
glaciation. The early advance was the Minnesota ice lobe, which
came through Iowa and entered the region from the northeast. The
Minnesota advance reached its maximum southern extent in the
vicinity of Weston, Missouri and Leavenworth, Kansas. The late
Independence glaciation advanced as two ice lobes. The Dakota lobe
crossed eastern Nebraska and entered Kansas from the northwest;
meanwhile, the Minnesota lobe advanced again into northwestern
Missouri. Both lobes reached farther south to the vicinity of
Topeka, Lawrence, Kansas City, and Independence along the Kansas
and Missouri river valleys. This incursion would have been the one
that brought the quartzite down from the southern part of Canada.
The stones that you see dropped here are the smallest of the
boulders as they were the lightest and able to be carried on top of
the ice sheet instead of being pushed along the front edge much
like a bulldozer.