THE COLDEST CLIMATE IN THE WESTERN NORTH PACIFIC DURING THE LAST 27KYR -THE FIRST APPEARANCE OF THE WORLD OLDEST STONE ARROWHEADS AND POTTERY IN HEINRICH EVENT I-

Sedimentary core MD01-2409 was collected off the coast of northern Japan in the western North Pacific. This core provided an excellent opportunity to quantitatively estimate paleo- atmospheric and sea surface temperatures by the positive correlation between both in summer during the last 27 kyr. The reconstructed millennial-scaled SST changes documented climate signals that originated in the northern hemisphere, such as Heinrich Event I, the YD, BA and pre-Boreal events, and the LGM. The benthic foraminifera U. akitaensis had a glacial–interglacial amplitude of d18O (1.36‰). The maximum d18O value was observed in the LGM due to maximal global ice volume. However, the minimum SST (8.7°C) was not recorded in the LGM but at 15.68 cal.kyr BP in Heinrich Event I. This corresponded to a period with an Asian Monsoon weakened by atmospheric circulation because the Japan Sea was so isolated that warm current from subtropical ocean could not bring heat energy to the northern North Pacific. The BA and pre-Boreal warm Episodes had very sharp warm peaks.

The world-earliest stone arrowheads (projectile points) and pottery (~15.5–16.5 cal.kyr BP) was excavated at the Odai–Yamamoto I site near Site MD01-2409, which experienced its coldest summer (SST of 8.7°C; AT of 5.2°C) around 15.68 cal.kyr.BP. The summer temperature was approximately 7–11°C lower than they are currently (SST of ~15.7°C and AT of ~16.7°C, respectively). The summer environment was a little colder than those experienced in the present-day coldest cities of Nosappu in northern Japan. Subsistence in a terrestrial environment would have been difficult for the people. However, marine products such as fish and shellfish would have been plentiful. These conditions were consistent with the evidence that the earliest pottery was predominantly used for cooking marine and freshwater resources and increased diversification in the range of aquatic products used. Cold climate induced in Heinrich Event I might work as a trigger to promote the first production of stone arrowheads and pottery in Far East.

Kawahata, H. et al. (2017) Quantitative reconstruction of temperature at Jomon site in the Incipient Jomon period in northern Japan and its implication for the production of early pottery and stone arrowheads. Quaternary Science Reviews, 157, 66-79.