Eruption age of Kannabe volcano using multi-dating: Implications for age determination of young basaltic lava flow
Eruption age of Kannabe volcano using multi-dating: Implications for age determination of young basaltic lava flow
复制标题
DOI：
10.1515/geochr-2015-0108
复制
发表时间：
2019-01
期刊：
影响因子：
1.2
通讯作者：
Y. Shitaoka;T. Saito;J. Yamamoto;M. Miyoshi;H. Ishibashi;Tsutomu Soda
中科院分区：
文献类型：
--
作者：
Y. Shitaoka;T. Saito;J. Yamamoto;M. Miyoshi;H. Ishibashi;Tsutomu Soda
摘要我们估算了位于日本西南部的神部火山的喷发年龄。虽然火山灰年代学和K-Ar定年法已经估算了喷发年龄，但其年龄测定的精度仍有改进的余地。广泛分布的火山岩对Kannabe火山的最新喷发时代有很好的限制。7.2-30 ka。我们应用古地磁测年的玄武质熔岩和光释光（OSL）测年的土壤层，这是与Kannabe火山。根据光释光测年结果，新测得的Kannabe火山渣上的土壤层年龄为21 ± 6 ka。同时，我们还进行了古地磁研究，以估算神田部玄武岩的喷发时代。从6个地点的Kannabe玄武岩熔岩23个岩石样品的古地磁数据显示出良好的相互一致性。在95%置信限为2.7°的情况下，反射磁化的平均值产生0.3°的下降角和65.9°的倾斜角。这一相对陡倾的古地磁方向与日本琵琶湖沉积物的古地磁长期变化数据有关。21.5 ka.根据多重年代测定的信息，我们推断Kannabe火山爆发的时间大约是在1980年。22 ka.这一结果为年轻玄武岩熔岩流的精确年龄测定提供了深刻的科学意义，目前几乎没有测年方法。
Abstract We estimated the eruption age of Kannabe volcano, located in southwestern Japan. Although the eruption age had been estimated using tephrochronology and K-Ar dating, the precision of its age determination left some room for improvement. The latest eruption age of Kannabe volcano is well constrained by wide spread tephras to ca. 7.2–30 ka. We applied paleomagnetic dating to a basaltic lava and optically stimulated luminescence (OSL) dating to a soil layer, which are associated with the Kannabe volcano. The soil layer above the Kannabe scoria was newly dated to be 21 ± 6 ka, as inferred from OSL dating. We also made paleomagnetic investigation to estimate the eruption age of the Kannabe basaltic lava. Paleomagnetic data of 23 rock samples from six locations in the Kannabe basaltic lava showed good mutual agreement. The average of remanent magnetizations yields declination of 0.3° and inclination of 65.9° with 95% confidence limit of 2.7°. This paleomagnetic direction with a relatively steep inclination is thought to be correlated with the paleomagnetic secular variation data of sediments in Lake Biwa at ca. 21.5 ka. Based on that information from multi-dating, we inferred that the Kannabe volcano erupted at ca. 22 ka. This result presents profound scientific implications for the precise age determination of young basaltic lava flow, for which few dating methods exist.