A date for volcanic eruption inferred from a siltstone xenolith

We present a TL age determination of a heated siltstone xenolith found at K ueishantao, a volcanic island 10 km off the northeastern shoreline of Taiwa n Before this study, no reliable numeric age determination had been obtaine d for the volcanic rocks. Its age has long been desired due to its active t ectonic environment. Previous studies of the other radiometric dating metho ds indicate a very young age for the eruption of this volcano, possibly lat er than 10 ka. However, reliable age is not allowed because it is younger t han the lower dating limit. Our result shows a TL age of 7 +/- 0.7 ka for t he lower part of the volcanic sequence, indicating that other volcanic erup tions occurred later than 7 ka. This finding suggests that the volcanic isl and, Kueishantao, has not ceased its igneous activity and is still active g eologically. (C) 2000 Elsevier Science Ltd. AII rights reserved.