Potassium-Argon

Potassium-argon dating is based on the nuclear decay of... 

Ruxton, B. P. and McDougall, I. (1967) Denudation rates in northeast Papua from potassium-argon dating of lavas. Am. ]. Sci. 265,545-561. 

The logic underlying carbon-14 dating differs from that for potassium-argon dating. Recall that bombardment of... 

The Juan Fernandez Islands, Chile, he east of the South American mainland at approximately 33°30 S, 80°W (Fig. 6.8). The archipelago consists of two main islands, Masatierra, which lies about 660 km from the mainland, and Masafuera, which lies 150km further west. A third, small island, Santa Clara, lies off the western end of Masatierra and probably was attached to Masatierra at one time. The ages of the islands have been determined using potassium-argon dating methods to be 5.8 2.1 million years for Santa Clara 4.23 0.16 million years for Masatierra and 2.44 0.14 million years for Masafuera (Stuessy et ah, 1984). 

Stuessy, T. F., Foland, K. A., Sutter, J. F., Sanders, R. W. and Silva, O. M. 1984. Botanical and geological significance of potassium-argon dates from the Juan Fernandez Islands. Science 225 49-51. 

Curtis GH, Hay RL (1972) Further geological studies and potassium-argon dating at Oludvai Gorge and Ngorongoro Crater. In Calibration of Hominid Evolution. Bishop WW, Miller JA (eds), Scottish Academic Press, Edinburgh... 

The Zag meteorite fell in the western Sahara of Morocco in August 1998. This meteorite was unusual in that it contained small crystals of halite (table salt), which experts believe formed by the evaporation of brine (salt water). It is one of the few indications that liquid water, which is essential for the development of life, may have existed in the early solar system. The halite crystals in the meteorite had a remarkably high abundance of 128Xe, a decay product of a short-lived iodine isotope that has long been absent from the solar system. Scientists believe that the iodine existed when the halite crystals formed. The xenon formed when this iodine decayed. For this reason, the Zag meteorite is believed to be one of the oldest artifacts in the solar system. In this lab, you will use potassium-argon radiochemical dating to estimate the age of the Zag meteorite and the solar system. 

Determine the age of the Zag meteorite, using potassium-argon (K-Ar) radiochemical dating. 

Potassium argon Relative amounts of parent-and daughter-isotope Volcanic rocks Textbox 15... 

The determination of the potassium-argon age of rock involves the following experimental stages ... 

Calculating the potassium-argon date of the mineral or rock... 

Knowing the total amounts of potassium-40 and of radiogenic argon-40 in a sample enables one to calculate first, their relative weight amounts and then, from these values, the age of the sample. The reliability of a potassium-argon date is generally expressed as a plus or minus value after the calculated date. 

Evemden, J. F. and G. H. Curtis (1965), The potassium-argon dating of late Cenozoic rocks in East Africa and Italy, Current Anthropol. 6, 343-385. 

Guillot, P. Y. (1985), Potassium-argon upper Pleistocene dating, Terra Cognita 5, 234-236. 

Guillot, P. Y. and Y. Comette (1986), The Cassignoll technique for potassium-argon dating, precision and accuracy Examples from the late Pleistocene to recent vol-canics from southern Italy, Client. Geol. (Isotopes Geoscience Section) 59, 205-222. 

Walter, R. (1997), Potassium-argon/argon-dating, in Taylor, R. E. and M. J. Aitken (eds.), Chronometric Dating in Archaeology, Advances in Archaeological and Museum Science Series, Vol. 2, Plenum, New York, pp. 97-126. 

Atoms of argon have 18 protons, whereas atoms of potassium have 19 protons. In order for the atomic weight of argon to be greater than that of potassium, argon atoms must have more neutrons. 

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