>The appearance of meanders and ox-bow lakes in flood
> plains is evidence of the vast age of such flood plains
>and of countless past floods. This evidence, from
>the field of hydraulics, should be of interest to Henry
>Morris. I wonder if anyone has ever undertaken to
>estimate the age of such flood plains. After all,
>the slow flow of a river causes the meanders; it can't
>be accelerated or the meanders disappear and you get
>canyons. It is a slow, nonlinear process. When
>I travel over the US in an airplane, I marvel at the
>complexity of sedimentary structure in these flood
>plains.
This source is rather difficult to get as it was a course I
attended given by a consultant. But I still have this
book. He calculated the time it would take to deposit a
buried Pennsylvanian delta in Oklahoma. There are
empirical relationships between river deposit sizes and the
amount of water and sediment that it can carry on average.
Don Swanson wrote:
>
"Calculations based on regional cross sections show that
approximately 1,500 cu. mi. or 16 trillion tons of clastic
material was deposit in the upper Morrow delta. ... Analogy
with the Brazos and Colorado (Texas) Rivers and empirical
relationship between thickness of point bars and stream
width and depth show that the probable average annual
discharge of the upper Morrow stage C stream was between
10,000 and 20,000 cu. ft. per sec. and that the stream
system added between 30,000,000 and 50,000,000 tons of
sediment a year. The Colorado River of Texas has an
average annual discharge of 4,374 cu. ft per sec and has
added material to its delta at the rate of 10,721 tons per
year. The Brazos River, with an annual discharge of 8,099
c. ft. per sec., is adding to its delta at the rate of
24,388,000 tons per year. The limiting rates of 30,000,000
and 50,000,000 tons per year gave 527,000 years as the
longest and 316,000 years as the shortest timespans
respectively, in which the 1,500 cu. mi. of upper Morrow
deltaic sediments could have accumulated." ~Donald C.
Swanson, Deltaic Deposits in the Pennsylvanian Upper Morrow
Formation of the Anadarko Basin., Privately published., p.
163.
This Morrow delta is merely 1 of the deltaic formations in
the geologic record. Paul is correct that if you speed the
process up you get no meanders, no point bars, ox-bow lakes
or other river deposits.
glenn
Foundation,Fall and Flood
http://members.gnn.com/GRMorton/dmd.htm