230Th dating of the speleothems from the "Grotta del Fiume-Grotta Grande del Vento" karst system in Frasassi (Ancona, Italy) and Paleoenvironmental implications

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Publication Date

January 1994

Abstract

Chronological measurements have been carried out on speleothems from the Grotta del Fiume-Grotta Grande del Vento karst system in Frasassi (Ancona, Italy) by means of the 230Th radiometric method in order to date hypogean karst levels and related geological events. Higher levels were found to be older than the lower ones according to standstills and sinkings of the water table. The dated speleothems from the first and second level formed less than 10,000 years ago; the minimum ages of the third and fifth levels, which are respectively 130,000 and 200,000 years old, were correlated to climatic events. Dating different portions of a speleothem allows the measurements of the radial and vertical accretion rates and their variation over time. Such data together with the 234U/238U activity ratio and the uranium content of the speleothems have been correlated with the climatic variations connected to the glacial cycles. The same data have been used to fit a hydrogeological model.

Document Type

Article

Identifier

SFS0072817_00001

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