Transcript The Geologic Record Sean D. Pitman, M.D. May 2007 www.DetectingDesign.com Features of the Geologic Column • Made of layers of sedimentary rock • Layers generally.

The Geologic Record
Sean D. Pitman, M.D.
May 2007
www.DetectingDesign.com
Features of the Geologic Column
• Made of layers of sedimentary rock
• Layers generally very flat/even relative to
each other
• Found generally all over the globe
– Some areas have few or missing layers
– Some areas have most if not all the layers
• Found on mountains such as the Swiss Alps,
Mt. Everest, American Rockies, Himalayas,
Appalachians, etc . . .
• Popularly thought to record millions and even
billions of years of Earth’s history
An Old Geologic Column?
Foot of the Book Cliffs
northwest of Grand Junction, CO
• Layers are flat/even relative to each other
• Layers often extend over hundreds of
thousands of square miles
• Where is the expected unevenness usually
seen with weathering?
Prof. Walter Veith – Turbidite Discussion
Walter Veith – Flames and Load Casts
The Speed of Erosion
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Rockies currently uplifted at 100-1000 cm/Kyr
No change in elevation
Erosion rate is matching uplift rate
Current uplift thought to have started 70
million years ago (Laramide Orogeny)
• An erosion rate of 100 cm/Kyr equals 1,000
meters of erosion per million years or an
incredible 70,000 meters in 70 million years
• Total thickness of layers in this region is
~3,500 meters – Why are they still there?
Mt. Everest
• Thought to be about 50 million
years old
• Himalayan erosion rate ~200cm/kyr
• Just 100 cm/Kyr of erosion equals
~50,000 vertical meters of erosion
in 50 My
• Still covered by Ordovician
limestone - only about halfway
down the column!
• Perhaps the layers used to be
much thicker?
– Only some 6000 m of sediment once
covered Everest
– Harutaka Sakai suggest half of
Everest slid off 20 Ma
– 3000m (Ordovician) exposed for
20 Ma and its still there? Really?
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Today’s continents average 0.875 km above sea level
Land surface area: 148,647,000 sq km
Cubic km above sea level: 130,066,125 km3
An average of several references suggest that about
13.6 km3 of solid material are carried by all the rivers
of the Earth into the oceans every year
– 31,000 million metric tons/year
• Time needed to erode away all land currently
above sea level: ~9.5 million years
http://worldatlas.com/geoquiz/thelist.htm
• Dott and Batten (1971) noted:
"North America is being denuded at a rate
that could level it in a mere 10 million
years, or, to put it another way, at the same
rate, ten North Americas could have been
eroded since middle Cretaceous time 100
m.y. ago."
C. R. Twidale recognized this problem as far
back as a 1976 in the American Journal of
Science:
“Even if it is accepted that estimates of the
contemporary rate of degradation of land surfaces
are several orders too high to provide an accurate
yardstick of erosion in the geological past there has
surely been ample time for the very ancient
features preserved in the present landscape to
have been eradicated several times over. . . The
survival of these paleoforms is in some degree an
embarrassment to all of the commonly accepted
models of landscape development.”
B.W. Sparks (1986) in Geomorphology:
"Some of these rates [of erosion] are obviously
staggering; the Yellow River could peneplain
[flatten out] an area with the average height that of
Everest in 10 million years. The student has two
courses open to him: to accept long extrapolations
of short-term denudation [erosion] figures and
doubt the reality of the erosion surfaces, or to
accept the erosion surfaces and be skeptical
about the validity of long extrapolations of present
erosion rates."
What About Human Impact?
“Humans have simultaneously increased
the sediment transport by global rivers
through soil erosion (by 0.6 - 2.3 billion
metric tons per year), yet reduced the flux
of sediment reaching the world’s coasts (by
0.3 - 1.4 billion metric tons per year)
because of retention within reservoirs.”
James P. M. Syvitski, Charles J. Vo¨ro¨smarty, Albert J. Kettner, Pamela Green Impact of Humans
on the Flux of Terrestrial Sediment to the Global Coastal Ocean, Science, VOL 308, 15 APRIL 2005
The Smooth Grand
Canyon Dome
Mini-Grand Staircase?
How did Red Butte Survive 5.5 million years?
Red Butte, Arizona
Beartooth Butte
• 300-400 million yeas old
• Same layers: Paleozoic
Beartooth Butte, Wyoming
Goosenecks of San Juan River
9 miles northwest of Mexican Hat, UT
Sinkholes in Permian Kaibab
Along right bank of Chevelon Fork (of the Little Colorado River)
18 miles southeast of Winslow, AZ
Trinidad Beach, CA
Dead Sea Sinkholes
Diversion of the Jordan River causing shrinkage of Dead Sea
by 3 feet per year
25 miles northwest of Twin Falls, ID
Dry Falls
Dry Falls
W
S
N
E
The Real Grand Canyon
Straight shot with few twists or U-shaped turns
Grander Canyon Cataract?
Grander Canyon Cataract?
Younger With Time?
• The lava dams were
once believed to have
eroded over tens to
hundreds of thousands
of years each
The Baby Grand?
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Ed Stiles, "Is the Grand Canyon a
Geologic Infant?" The University of
Arizona News, OPI, July 18, 2002
2000 foot GC lava dams collapsed
within 80 minutes!
Huge wall of water suddenly released
“37 times the flow of the largest
flooding of the Mississippi River”
• Huge amounts of rapidly moving water equal
huge amounts of rapid erosion
• Certain portions of the Grand Canyon, once
thought to be up to 5 million years old (Marble
Canyon and the Inner Gorge), “may be as
young as 600,000 years old”
• Initial dating of 5 My backed up by K/Ar dating,
now thought to be inaccurate in this region due
to the lack of complete removal of the argon
daughter product at the time of initial formation
of the lava dams
• Mather Gorge and Holtwood
Gorge in Pennsylvania
• Used to be 180 million years old
• July, 2004: Luke J. Reusser, a
geologist at the University of
Vermont in Burlington, used
measurements of beryllium-10
that builds up in quartz when
exposed to cosmic rays to redate these gorges to just 13,000
years
• Younger now by 4 orders of
magnitude!
Monument Valley
Over 50 million years of erosion?
Trinidad Beach, CA
Walter Veith – Miniature Monument Valley
Walter Veith – “Town Hall”
Trinidad Beach, CA
Arches National Park
100 million years of erosion
in southeastern Utah?
• More than 2,000 arches within 73,000 acres
of southeastern Utah
• Once buried by almost 1 mile of sediment
• Local uplift caused cracks to form 100 million
years ago
• Subsequent erosion expanded the cracks to
form the fins and arches that we see today
Arches National Park, UT
Landscape Arch
• Erosion rates too high for the
layers to still be there, much less
thin walled high-relief fins to
survive for tens of millions of years
• Note also that only the surface
layers of these fins show any
evidence of significant erosion
Paraconformities
Redwall
N.D. Newell, in the 1984 issue of the Princeton
University Press, made a very interesting and
revealing comment concerning this
paraconformity phenomenon:
"A puzzling characteristic of the erathem
boundaries and of many other major biostratigraphic
boundaries [boundaries between different types of
fossil groups] is the general lack of physical
evidence of subaerial exposure. Traces of deep
leaching, scour, channeling, and residual gravels
tend to be lacking, even where the underlying rocks
are cherty [soft] limestones. These boundaries are
paraconformities that are usually identifiable only by
paleontological [fossil] evidence."
• In an earlier paper Newell noted:
"A remarkable aspect of paraconformities in
limestone sequences is general lack of evidence
of leaching of the undersurface. Residual sods
and karst surfaces [irregular erosion channels]
that might be expected to result from long
subaerial exposure are lacking or unrecognized. . .
The origin of paraconformities is uncertain, and
I certainly do not have a simple solution to this
problem."
Angular Unconformity
Happened slowly? – or catastrophically?
Clastic Dikes
Varves
• Lambert and Hsü (1979) measured "varves" in Lake
Walensee, Switzerland and found up to five laminae
deposited during one year
• From 1811, which was a clear marker point (because
a newly built canal discharged into the lake), until
1971, a period of 160 years, they found the number
of laminae ranged between 300 and 360 instead of
the expected one per year or 160
– Our investigations supported de Geer's first
contention that sediment-laden floodwaters could
generate turbidity underflows to deposit varves,
but threw doubt on his second interpretation that
varves or varve-like sediment are necessarily
annual. (Lambert and Hsü, p. 454)
Continental Drift
• 2000 years ago Emphesis was a
seaport city, now it is 5 miles inland
• Louisiana coastline is being lost a
25sq. miles per year
• US spends $500,000,000 to prevent
erosion of the east and west coasts
• Florida spends $8,000,000 per year
• Past 50 years Washington state has
lost over 300 meters of certain of its
coastlines
• Northern and north center regions of
California erode at about 30 cm/yr
with some areas (Capitola) eroding
at up to 1.5 m/yr (Plant and Griggs
1991).
http://bonita.mbnms.nos.noaa.gov/sitechar/main.html
Trinidad, Northern California
• Texas is loosing between 0.3 and
15 meters of coastline per year
• Major Gulf-coast storms can cause
30-40 meters of erosion in 1 day
• Landmark lighthouse of Cape
Hatteras, North Carolina, built 1500
m inland in 1869 had to be moved
another ~1000 m to avoid collapse
into the ocean
– About 10 meters of erosion/year
• True all over the world
• Japan literally spends billions of
dollars to prevent erosion
“Significant Losses From Coastal Erosion Anticipated Along U.S. Coastlines,”
Federal Emergency Management Agency - June, 2000 http://www.fema.gov/nwz00/erosion.shtm
• What would an average of just 1 cm of
coastal erosion/deposition do to the shape of
the continents in 200 million years?
• No big deal – right?
• The change would be two thousand
kilometers (1,200 miles) . . . Enough to erode
(or deposit) half way through or onto the
United States on all sides!
• Would the puzzle still fit?
• Why are all deltas young?
• Gulf of Mexico filled in 10 Ma
Questions?
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