Radioactive decay age dating

The claimed age of 1,103±66 million years was obtained using the rubidium-strontium isochron method with 10 samples and has been regarded as the best radioactive dating result for any Grand Canyon rock unit.

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However, what ages do these same methods yield when applied to rocks for whose formation there are independent cross-checks? There are up to 160 volcanic cones on the plateau to the north of the Canyon rim out of which these basalt lavas flowed.

The eruptions were so recent, occurring after the Grand Canyon formed, that some of these basalt lava flows cascaded like molten waterfalls over the Canyon rim, down the Canyon walls and into the Canyon, where they formed dams that temporarily blocked the flow of the Colorado River .

That is, their rubidium-strontium composition has nothing to do with their age, but everything to do with their source!

However, the molten rock that produced the “ancient” Cardenas Basalt lavas also came from the same region of the earth’s mantle beneath the Grand Canyon.

This is identical to the rubidium-strontium isochron age of 1,111±81 million years for the Cardenas Basalt lavas near the bottom of Grand Canyon strata sequence So how can the youngest basalt lava flows in Grand Canyon, whose eruption was possibly witnessed only thousands of years ago, yield the same radioactive rubidium-strontium age of 1.1 billion years as some of the oldest basalt lava flows at the bottom of the Canyon?

Answer: The molten rock that produced the young basalt lava flows came from deep inside the earth, from what geologists call the earth’s mantle; so these lavas have inherited this rubidium-strontium composition from their mantle source.It’s even possible the American Indians may have witnessed some of this awesome spectacle.1 Yet, when applying the widely accepted assumptions of secular geologists, these basalt flows yield potassium-argon model ages of around 500,000–1 million years.Worse still, their rubidium-strontium isochron age is 1,143±220 million years!In any case, could it be that these radioactive clocks have previously ticked at faster rates than they do today?There is much convincing evidence to support this possibility (see Further Reading at end of article).And how can we know how much radioactive decay occurred in their mantle source before these lavas erupted?

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