Holocene sea-level change and Antarctic melting history derived from geological observations and geophysical modeling along the Shimokita Peninsula, northern Japan

A Mid to Late Holocene sea-level record based on combined geomorphological, geological and micropaleontological observations was obtained from well-developed wave cut benches subaerially exposed along the Shimokita Peninsula, northern Japan. Results indicate that the benches were formed during mid to late Holocene sea-level transgressions, reaching a maximum highstand level of 2 m above present at about 4,000 years ago. This timing corresponds to an abrupt, order of magnitude decrease in sedimentation rate as recorded in a core recovered from proximal Mutsu Bay. In addition, glacio-hydro-isostatic adjustment due to crustal deformation in response to postglacial sea-level rise was modeled, and results are consistent with the reconstructed local 2 m highstand. Given that meltwater contributions from the major North American and European ice sheets had largely ceased by 7,000 years ago, these independent lines of evidence, taken together, indicate that melting of the Antarctic ice sheet ended by 4,000 years ago. Citation: Yokoyama, Y., J. Okuno, Y. Miyairi, S. Obrochta, N. Demboya, Y. Makino, and H. Kawahata (2012), Holocene sea-level change and Antarctic melting history derived from geological observations and geophysical modeling along the Shimokita Peninsula, northern Japan, Geophys. Res. Lett., 39, L13502, doi:10.1029/2012GL051983.