| Abstract |
Paleomagnetic measurements were made on the Pliocene Watari andesite, middle Pleistocene Hisatsu volcanic rocks and three younger pyroclastic flow deposits collected from the Hitoyoshi basin, Kumamoto... Prefecture. The remanent magnetization was measured on about 100 oriented samples from 19 sampling sites. Stability of the NRM was tested on one or two pilot samples from each sampling site by alternating field demagnetization. The Watari andesite shows the reversed magnetization. The Hisatsu volcanic rocks, which have been referred to middle Pleistocene, show the reversed magnetizations. Accordingly, they seem to have been formed in the younger part of the Matuyama reversed epoch. Three pyroclastic flow deposits (lower Kakuto, upper Kakuto and Aso-4) show the normal magnetizations. The fission-track age of the lower Kakuto pyroclastic flow deposit corresponds to the Blake event (108, 000-114, 000 y. B. P.) in the Brunhes normal epoch, which was first reported by SMITH and FOSTER (1969). Such a reversed event, however, was not recognized in this pyroclastic flow deposit.show more
|
Export Mendeley
1302_p127