Re: Response to Why YEC posting

From: Allen Roy (
Date: Wed Aug 22 2001 - 17:36:58 EDT

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      From: Charles Carrigan
        1: I know you are aware of the Uinkaret Plateu lava flows which flowed down
        into Grand Canyon. These have been dated by a Pb-Pb isochron age in the
        neighborhood of 2.6 billion years and by a Rb-Sr isochron date somewhere
        around 1.34 billion years. Everyone rejects these computed ages because it
        is obvious that the lava cannot be that old. They must be younger than
        Grand Canyon which is variously dated between 1 and 5 million years. An
        assortment of reasons concerning the "original abundances of isotopes" have
        been proposed to try to explain the discrepancy, but the most important
        point is that the dates are rejected because it is "known" that the lava
        cannot be that old. The rocks are assumed to be young therefore computed
        dates which indicate vast ages are rejected.

        Pb-Pb: Everson, 1979, "Regional Variations in the Lead Isotopic Characteristics of Late Cenozoic Basalts from the Southwestern U.S." Unpublished dissertation, 1979). And: Alibert, et. al., 1986, "Isotope and trace element Geochemistry of Colorado Plateau Volcanics."

        Rb-Sr: Austin, ed. 1994, "Grand Canyon, Monument to Catastrophe," pg. 125
        The age of Grand Canyon has been commonly estimated at 5 million years in nearly all publications about the Park. Just last year, after a convention of nearly all geologists which have been studying Grand Canyon forever, the age of 1 million years has been proposed. I can't find the source right off.

        2: Also in Grand Canyon are the Cardenas Basalts which are dated by a Rb-Sr
        isochron near 1.07 billion years. Because the Cardenas Basalts are among the
        oldest exposed rocks in Grand Canyon everyone assumes that the Cardenas
        Basalt's are old enough for the computed dates to be accepted as valid.
        Rb-Sr: Beus and Morales, eds. 1990, "Grand Canyon Geology," pg 35,

        Can you provide references for these dates please?

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