#Glacial Geology
12 messages in this thread
Hi !!
Anyone have any good suggestions for information on the glacial history of
Washington State, or expanded to the Pacific Northwest ???? I have found
various papers on limited sites or short generalizations in texts, but I am
looking for the history for the Cascades and the Olympics (and surrounding
areas). All suggestions welcome !!!! thanks —
Harris & Tuttle's book "Geology of National Parks" has what I would call
thorough summaries of all aspects of the geology of Olympic, North Cascades,
and Crater Lake and Ranier, including glaciation, but it may still be less than
you want. Its a good book though.
Regards, Dick Gibson
Two suggestions.. (I cannot testify to availability in bookstores or libraries)
McKee, Bates: Cascadia McGrawHill, 1972 ISBN 07-045133-8
This is a beautifully illustrated book, nice maps, and while no longer
completely up-to-date would be a good introduction.
Allen, John Eliot; and Burns & Sargeant: Cataclysms on the Columbia. Timber
Press (Portland), 1987 ISBN 0-88192-076-3
Challenges the long held diastrophism theories about geological events,
showing that in late Pleistocene times a major and periodic cataclysmic flood
came down the Columbia with devastating results, creating geological features
clearly visible today. This flooding was due to the release of a vast amount
of water held behind an ice floe which periodically would rupture, in the
neighborhood of what is now Missoula, MT. The flood would plunge down the
Columbia River tearing out most everything in its path, and reorganizing the
geography of the Willamette Valley, the Columbia Gorge, etc.
Hope this helps..
Bill
Cataclysms on the Columbia is interesting reading, but the ideas of the floods
were proposed long before 1987 (J. H. Bretz published the first major report on
them in 1959) and they are now long accepted as being what created the
"Channeled Scablands" of E. Washington, and Dryfalls near Grand Coulee, giant
ripple marks in the same area, etc. The ice dam that formed glacial Lake
Missoula (around 20,000 years ago was at the north end of present Lake Pend
Oreille, just north of where I currently sit in N. Idaho. Incidently, the
floods happened several times and the last (and possibly greatest) released a
volume of water equal to a flow about 10 times the present flow of all the
rivers in the world (9.5 cubic miles per hour).
Just incase anyone is interested.
Lanny
Correction..
Thanks Lanny. The book I cited essentially was a review of how Bretz' theory
was not accepted for some time, due to conservatism of the geology community
and its obsession with slow processes as the ONLY way geological events were
supposed to occur. The importance of the book is that it shows first of all
how the theory was arrived at (geological evidence) and then how it was ignored
for so long.
It was one of hell of a flood, that last one!
Bill
Yeah, many of us geologists like to think things happen only in "geologic
time". I wonder what some of them think of such things as Mt. St. Helens nasty
little eruption in 1980.
Now those slow thinkers who do accept Bretz's floods believe there were
something like 7 of them. Pretty difficult setting up your teepee there for a
few years!
Lanny
Hi Lanny, Bill, and everyone,
I'm definitely not a geologist (physicist, actually) but a question has been
puzzling me for many years.
Basically, I'm trying to find out the generally accepted time for the end of
the last ice age in the Midwest US.
The reason is that along the west "coast" of Iowa are a series of hills called
the "loess" hills. The hills in the rest of Iowa (and surrounding states) are
mostly glacial moraines (except for the "driftless area" in NE Iowa and SW
Wisconsin).
My problem is that the loess hills were created by wind-blown dirt, and most of
the descriptions I've been able to find seem to assume they are millions of
years old. The hills are in a band about 300 miles N-S and 10-20 miles E-W
with a relief of about 400 feet along the Missouri river (the northern 30 miles
or so are along a smaller stream).
It seems to me that these hills had to be created after the ice finally melted
which implies a tremendous wind at one or more times since the ice age ended.
Can anyone help ease my puzzlement?
Thanks,
Dean
Sorry Dean,
But I can't help much. I don't have any geology texts handy that would
specifically show where the southern extent of the ice was in the Midwest. The
ending it would have to be much the same as elsewhere, and that was generally
thought to be a little less than 10,000 years ago (I haven't kept up on any
refinements of that.). If the ice extended south of where the loess hills are,
then obviously these hills have to be younger than the last ice sheet, but they
could well be S. of the ice sheet and have originated from its action, see
below.
We have the same thing in this area, primarily in E. Washington from just S. of
Spokane south and to the southwest to Richland. The loess here is believed to
have originated as the fine material that originated from the glacial outwash
(with a lot of Cascade volcanic "ash" thrown in) then was blown back NE'ly by
the winds. It doesn't take very strong winds. The loess hills are where the
wheat of E. Washington is grown, and with all those fallow fields, any good
windstorm (about 40 mph will do it) will pick it up and dump the stuff on me in
N. Idaho. This is really a lot of fun, because when the storm gets here, it
generally rains, so what we get is a "mud storm"!
Lanny
Hi,
Don't forget the Washington Div. of Geology and Earth Resources publications,
especially the following:
Washington Geolgy and Resources by CD Campbell, Info Cir 22R
Origin of Cascade Landscapes by Mackin & Cary, Info Cir 41
Tertiary Geologic History of Western Oregon and Washington
by PD Snavely and HC Wagner, Rept of Inv 22
Geologic History and Rocks and Minerals of Washngton
by VE Livingston, Info Cir 45
These are all somewhat dated, but the basics still hold true. They may all be
out of print, but are available in libraries.
Phone the Division at 206-902-1450.
Lanny
Harriet –
You might try to get a hold of a copy of Geological Excursions in the Pacific
Northwest, Field trip notes from the 1977 Annual Society meeting, published by
the Dept. of Geology, Western Washington Univ., Bellingham, WA 98225. Edited
by Brown and Ellis.
Section 13 covers Glaciation and Catastrophic Flooding of the Columbia Plateau.
There are other references to glaciation in the other 12 field trips, but
generally only in passing comment.
Other references from my library on Glaciation:
Fire and Ice: The Casade Volcanoes
Stephen Harris
ISBN 0-89886-009-1
Pub. The Mountaineers
The Shape and Form of Puget Sound
Robert Burns
ISBN 0-295-96184-8
Pub. Puget Sound Books
After the Ice Age: the Return of Life to Glaciated North America
E.C. Pielou
ISBN 0-226-66811-8
Pub. University of Chicago Press
I will continue looking for other references for you.
Regards –
Michael (in Anacortes)
This may be in the realm of "generalizations from texts", but have you tried
the Roadside
Geology series of books? (Roadside Geology of Washington, Roadside Geology of
Idaho, et al.) They are readily available at bookstores such as Waldenbooks
and B.
Dalton.
Liz Wavada
Spokane
Liz,
Another "Roadside Geology" lover? Me, too. I've used Texas, Utah and Arizona
lately. I wish they'd come out with one for my state, Florida. But a friend
and I joked that it would only end up being a pamphlet, continually repeating:
on your left is swamp. On your right is…swamp. And then over there
is…more swamp (formed over eons and eons of time ;-)) Seriously, it would be
a little more interesting than that. What books have you used/did you really
like? What other geo books do you recommend? I'm a John McPhee fan, at the
moment.
Shannon