Discordant Potassium-Argon Model and Isochron "Ages" for Cardenas Basalt (Middle Proterozoic) and Associated Diabase of Eastern Grand Canyon, Arizona

Download PDFDownload Discordant Potassium-Argon Model and Isochron "Ages" for Cardenas Basalt (Middle Proterozoic) and Associated Diabase of Eastern Grand Canyon, Arizona PDF

by Steven A. Austin, Ph.D. and Andrew A. Snelling, Ph.D.

Presented at the Fourth International Conference on Creationism, Pittsburgh, Pennsylvania, August 3–8, 1998. Published in: Proceedings of the Fourth International Conference on Creationism, R. E. Walsh (editor), pp. 35–51, 1998.

© 1998 Creation Science Fellowship, Inc., Pittsburgh, Pennyslvania, USA. All Rights Reserved.

Abstract

For more than twenty years it has been known that the Rb-Sr and K-Ar systems give discordant “ages” for Cardenas Basalt and associated Proterozoic diabase sills and dikes of Grand Canyon. Thirteen new K-Ar analyses of Proterozoic mafic rocks of Grand Canyon are added to nine published K-Ar analyses. We report a new fourteen-point K-Ar isochron “age” of 516 ± 30 Ma which is strongly discordant with the published Rb-Sr isochron “age” of 1.07 ± 0.07 Ga for Cardenas Basalt. By more than doubling the K-Ar data set we can test explanations for why the discordance exists. Advocates of the Rb-Sr isochron, recognizing the strong geochemical similarity of rubidium and potassium, have not argued for significant potassium addition to these rocks. Addition of potassium during alteration of these rocks would explain the anomously young K-Ar age, but it would also add rubidium and invalidate the Rb-Sr isochron age. Instead, advocates of the Rb-Sr isochron have argued only for significant argon loss. Two argon loss models (episodic loss and continuous loss) are tested in an attempt to explain why these altered rocks have about half the 40Ar required by the conventional Rb-Sr interpretation. Both argon loss models, although attempting to maintain the assumptions of conventional geochronology, fail to explain the data, especially the new data we offer. Three models are proposed as alternatives to argon loss models, but these invalidate using the K-Ar system as conventional geochronology would assume.

Keywords

Basalt, Diabase, Grand Canyon, Potassium-Argon Dating, Model “Ages”, Isochron “Ages”, Discordance, Argon Leakage Models, Inheritance, Mixing, Change of Decay

For Full Text

Please see the Download PDF link above for the entire article.

The Latest
NEWS
Giving Day Today!
Hello, Friends. North Texas Giving Day is finally here! Will you partner with us? Your generosity will help ICR proclaim the truth and accuracy...

TESTIMONIALS
Answers to Build Your Faith
Hello, I’m Bill West, ICR’s System Administrator. Thirteen years ago, a man dedicated to God’s Word shared the gospel with me, and...

NEWS
Newly-Discovered Brain Cell
Someone said the three-pound human brain is the most complex and least-understood biological structure in the known universe. Scientific research regarding...

TESTIMONIALS
Biblical Creation for Everyone
Hello, my name is Rebecca Barber. I work here at ICR’s School of Biblical Apologetics, and I recently finished a project detailing the history...

NEWS
WWII Plane Found Frozen in Greenland Ice
A team has located a World War II P-38 Lightning fighter plane beneath more than 300 feet of ice in Greenland. They first found hints of the plane’s...