Grand Canyon older than previously thought

[Gooch's dad]

Graned Canyon is 17 million years old, 3 times older than previous estimates (http://news.yahoo.com/s/afp/20080308/ts_afp/usgeologygrandcanyon;_ylt=AnTzEMNu9.RYmOVCbZgy6huG Wo14)

A new dating technique has put the age of the Grand Canyon at 17 million years old, three times older than earlier estimates, according to a report in the latest edition of the journal Science.
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The latest in uranium-lead isotope dating allowed researchers to study the canyon's "cave clouds", the mamillary coatings of carbon deposits that gather on the canyon walls at or near the water table, the journal said in its edition released Thursday.

I remember reading that there were two competing estimates for the age of the canyon. One model had it at roughly 5 million years old, the other had it much older, at maybe 60 million years. I guess the 5 million year estimate was the most generally accepted estimate.

Cool stuff!

[dancer_rnb]

Isn't there an estimate of less than 6000 years?:wave:

runs away.......

[Comfortably Numb]

A new dating technique has put the age of the Grand Canyon at 17 million years old, three times older than earlier estimates, according to a report in the latest edition of the journal Science.

There ya go, none of those dating techniques work. They all give different answers.:rolleyes: :D

[The 800# Gorilla]

I have found that my dating techniques did not work very well either.

[Ian Nerr]

Dating is overrated.

[llanitedave]

The problem with the Grand Canyon is that it seems to have formed in various stages. The upper canyon west of Kanab Creek may indeed be 17 million years old, while the lowermost parts of the canyon, including Granite Gorge, is probably much younger.

I'm extremely skeptical of the the interpretation using cave deposits. No problem with the timing of the lowering of the regional water table, but there's no reason to assume that the water table's lowering and the canyon's formation coincide.

There are some good geologic controls in the Lake Meade and Pierce Ferry region that still point to the 6-million year age of the Colorado River breakout through its current channel to the Gulf of California. Those features have not been refuted by the cave deposits.

[Apostasius]

I think this is the reference from the article:

Age and Evolution of the Grand Canyon Revealed by U-Pb Dating of Water Table–Type Speleothems

by Polyak, Hill, and Asmerom

Abstract:

The age and evolution of the Grand Canyon have been subjects of great interest and debate
since its discovery. We found that cave mammillaries (water table indicator speleothems)
from nine sites in the Grand Canyon showed uranium-lead dating evidence for an old western
Grand Canyon on the assumption that groundwater table decline rates are equivalent to incision
rates. Samples in the western Grand Canyon yielded apparent water table decline rates of
55 to 123 meters per million years over the past 17 million years, in contrast to eastern
Grand Canyon samples that yielded much faster rates (166 to 411 meters per million years).
Chronology and inferred incision data indicate that the Grand Canyon evolved via headward
erosion from west to east, together with late-stage (~3.7 million years ago) accelerated incision
in the eastern block.