HOLOCENE PALEO-SECULAR VARIATION IN KOREA: A POTENTIAL REGIONAL AGE CONSTRAINT TOOL

Abstract

The geomagnetic field, like fossils, leaves information of its past direction and intensity on geological media such as rocks and sediments. The fossilized records not only provide information about the electro-magnetic dynamics of the inner Earth, but also serve as a global benchmark for a sediment age constraint. In particular, Holocene geomagnetic fields have been actively studied in North America and Europe and are used as data sets for global prediction models of paleo-secular variation (PSV). However, in Asia, there exists a large inaccuracy between the global PSV models and the actual measurements due to a lack of Asian paleomagnetic data. Here, we report the first successive Holocene PSV in Korea excavated from the sediments core in the mouth of Seomjin River (SJ-4). The sediment ages were determined by carbon isotopes using clam shells that were expected to have little migration. Considered sedimentation rates, regular 2.5 cm or 5 cm paleomagnetic sampling intervals were selected to compensate <50 years age window for the period of ~1 &#8211 10 kyr BP.r Earth, but also serve as a global benchmark for a sediment age constraint. In particular, Holocene geomagnetic fields have been actively studied in North America and Europe and are used as data sets for global prediction models of paleo-secular variation (PSV). However, in Asia, there exists a large inaccuracy between the global PSV models and the actual measurements due to a lack of Asian paleomagnetic data. Here, we report the first successive Holocene PSV in Korea excavated from the sediments core in the mouth of Seomjin River (SJ-4). The sediment ages were determined by carbon isotopes using clam shells that were expected to have little migration. Considered sedimentation rates, regular 2.5 cm or 5 cm paleomagnetic sampling intervals were selected to compensate <50 years age window for the period of ~1 &#8211 10 kyr BP.