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The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 51 (1967)

Issue: 3. (March)

First Page: 479

Last Page: 480

Title: Villafranchian Age and its Radiometric Dating, II: ABSTRACT

Author(s): Donald E. Savage, Garniss H. Curtis

Article Type: Meeting abstract

Abstract:

The Villafranchian, though identified by non-marine phenomena, was one of the most precisely typified of the commonly used European Cenozoic Stages-Ages. Pareto (1865) gave exact geographic location and characteristic rocks of his stratotype for Villafranchian and listed the fossils that were known (three proboscidean species).

Villafranchian has been applied throughout Eurasia and Africa on the basis of a characteristic array of species of mammals. These species were obtained first from sites in Italy and France that were believed to be the same age as Pareto's Villafranchian. Validity and utility of the Villafranchian, as recognized through most of the Eastern Hemisphere, are not vitiated because some of its characterizing mammalian assemblages are younger than the type or because its lower boundary may not coincide with the currently accepted lower boundary of the Quaternary.

Large mammals now known from the stratotype, together with small mammals, mollusks, and plants

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recently collected, will provide a more secure paleontologic basis for correlation with type-Villafranchian ecology.

Although no materials suitable for radiometric dating of type Villafranchian has been found, volcanic rocks associated with the correlative Etouaires fauna near Issoire, France, have yielded a K/Ar date of 3.4 m.y. The nearby younger Villafranchian fauna of Roca Neyra is 2.5 m.y. In beds from a zone between these two faunas is the fossil flora of Boissac, of perimediterranean type dominated by deciduous trees and containing bamboo.

The oldest geological indications of cold climate that have been dated in the Auvergne of France are at Coupet (solifluction), 1.9 m.y., and Vazeills (crioturbated earth), 1.8 m.y. Coupet also has a fauna, thought by Bout to be mid-Villafranchian.

The oldest glacial deposit dated from the Northern Hemisphere (Sierra Nevada) is 2.7 m.y., whereas the oldest evidence of Pleistocene cold climate in the Southern Hemisphere (New Zealand) is slightly older than 2.5 m.y.

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Copyright 1997 American Association of Petroleum Geologists