Once Earth was destroyed to make room for the new superhighway, and the replica we now live on was WAY over budget, cutbacks had to be enacted somewhere.
Posted on 08/31/2015 8:33:00 AM PDT by fishtank
Makes sense. I couldn't see how ice dams in Minnesota or South Dakota could block enough water to carve the Grand Canyon without some major excavations in between. Ash from something like the Yellowstone volcano would make more sense.
Matt D. Andersa, Joel L. Pedersona, , , Tammy M. Rittenourb, 1, Warren D. Sharpc, John C. Gossed, Karl E. Karlstrome, Laura J. Crosseye, Ronald J. Gobleb, Lisa Stocklif, Guang Yangd. Pleistocene geomorphology and geochronology of eastern Grand Canyon: linkages of landscape components during climate changes.
[....]
Previous workers attributed these deposits in eastern
Grand Canyon to glacial–interglacial-scale climate
fluctuations. Machette and Rosholt (1991) suggested
that mainstem terrace formation in eastern Grand
Canyon was caused by changes in sediment yield and
vegetation cover in the Colorado River catchment.
Lucchitta et al. (1995) likewise proposed that glacial
advances in headwater areas of the Colorado River
catchment during the Pinedale (Marine Isotope Stage
[MIS] 2) and Bull Lake (MIS 6) glaciations increased
sediment load and caused two of the aggradation
episodes they identified in eastern Grand Canyon. They
also suggested that a mainstem Holocene aggradation
episode was the result of local reworking of older
alluvial and colluvial deposits due to reduced vegetation
cover and intense monsoonal precipitation. Other
origins proposed for the eastern Grand Canyon deposits
include regional Miocene–Pliocene aggradation due to
dryer climate (Elston, 1989), and deposition in lakes
behind lava-dams in western Grand Canyon (Hamblin,
1994).
http://www.usu.edu/geo/pederson/Anders%20et%20al.%202005%20QSR.pdf
Peak discharge of a Pleistocene lava-dam outburst flood in Grand Canyon, Arizona, USA
Quaternary Research
By:C.R. Fenton, R.H. Webb, and T.E. Cerling
DOI: 10.1016/j.yqres.2005.09.006
The failure of a lava dam 165,000 yr ago produced the largest known flood on the Colorado River in Grand Canyon. The Hyaloclastite Dam was up to 366 m high, and geochemical evidence linked this structure to outburst-flood deposits that occurred for 32 km downstream. Using the Hyaloclastite outburst-flood deposits as paleostage indicators, we used dam-failure and unsteady flow modeling to estimate a peak discharge and flow hydrograph. Failure of the Hyaloclastite Dam released a maximum 11 ?? 109 m3 of water in 31 h. Peak discharges, estimated from uncertainty in channel geometry, dam height, and hydraulic characteristics, ranged from 2.3 to 5.3 ?? 105 m3 s-1 for the Hyaloclastite outburst flood. This discharge is an order of magnitude greater than the largest known discharge on the Colorado River (1.4 ?? 104 m3 s-1) and the largest peak discharge resulting from failure of a constructed dam in the USA (6.5 ?? 104 m3 s-1). Moreover, the Hyaloclastite outburst flood is the oldest documented Quaternary flood and one of the largest to have occurred in the continental USA. The peak discharge for this flood ranks in the top 30 floods (>105 m3 s-1) known worldwide and in the top ten largest floods in North America. ?? 2005 University of Washington. All rights reserved.
http://pubs.er.usgs.gov/publication/70030593
CHAPTER 2
PALEOZOIC STRATIGRAPHY OF THE GRAND CANYON
PAIGE KERCHER
Very interesting. Thanks
Late Oligocene–early Miocene Grand Canyon:
A Canadian connection?
James W. Sears, Dept. of Geosciences, University of Montana,
Missoula, Montana 59812, USA, james.sears@umontana.edu
ABSTRACT
Remnants of fluvial sediments and their paleovalleys may map
out a late Oligocene–early Miocene “super-river” from headwaters
in the southern Colorado Plateau, through a proto–Grand Canyon
to the Labrador Sea, where delta deposits contain microfossils
that may have been derived from the southwestern United States.
The delta may explain the fate of sediment that was denuded
from the southern Colorado Plateau during late Oligocene–early
Miocene time.
I propose the following model:
1. Uplift of the Rio Grande Rift cut the southern Colorado
Plateau out of the Great Plains at 26 Ma and tilted it to the
southwest.
2. The upper Colorado River and its tributaries began as consequent
streams that flowed down the structural plunge of the
basin toward the southwest corner of the Colorado Plateau,
where the river passed through a Paleogene canyon.
3. The river turned north in the Lake Mead region to enter
Paleogene rifts of the eastern Great Basin.
4. NE-trending grabens across the Idaho and Montana Rockies
provided the final link to the Great Plains, where the Miocene
drainage joined the “Bell River” of Canada, which drained to
the Labrador Sea.
5. Faulting and volcanism began to segment the paleo-river by
ca. 16 Ma.
6. Faulting dammed Miocene Grand Canyon, creating a large
ephemeral lake that persisted until after 6 Ma, when the
Colorado River was captured by the Gulf of California.
7. The resulting shortcut to sea level greatly increased the gradient
of the Colorado River, leading to headward incision of the
Inner Gorge of Grand Canyon along the trace of the Miocene
bedrock valley f loor and renewed late Miocene-Holocene
erosion of the Colorado Plateau.
8. The Yellowstone hotspot cut the river off in Idaho after 6 Ma.
9. Pleistocene continental glaciation destroyed the Canadian
Bell River and diverted Montana’s drainage into the modern
Missouri River.
http://www.geosociety.org/gsatoday/archive/23/11/pdf/i1052-5173-23-11-4.pdf
The programmer was in a hurry and figured no one would notice...
Once Earth was destroyed to make room for the new superhighway, and the replica we now live on was WAY over budget, cutbacks had to be enacted somewhere.
I live on the Balcones Escarpment. It starts just south of Dallas and ends at the southern end of the Rio Grande Rift. The uplift along the Balcones fault ended about 16 Ma, about the time of the faulting and volcanism started in point 5.
Our house is only a few miles from the Canyon Gorge, and we have toured the gorge. It takes several hours to walk from top to bottom, and takes you through 110 Ma of geologic history, uncovered just 13 years ago.
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