Climatic reconstruction at the Sannai-Maruyama site between Bond events 4 and 3—implication for the collapse of the society at 4.2 ka event

Abstract

The Jōmon period/culture corresponds to the Neolithic period/culture in Japanese prehistory. The Sannai-Maruyama site (5.9-4.2 cal. kyr BP), the most famous, the largest, and the well-studied mid-Holocene (mid-Jōmon) archeological site inhabited by hunter-gatherers with sedentary lifestyle in northern Japan, started at early Bond event 4 and collapsed at late Bond event 3 (4.2 cal. kyr BP at the boundary between mid-Holocene, Northgrippian, and late-Holocene, Meghalayan), synchronous with the decline of the north Mesopotamian civilization and the Yangtze River civilization in China. Alkenone sea surface temperatures (SSTs), a proxy for early-midsummer SSTs, generally suggest that the early-midsummer SSTs (and atmospheric temperatures (ATs)) at 41°00′ N, 140°46′ E, about 20 km north to the Sannai-Maruyama site, located in Aomori Prefecture, peaked around 4.8-4.3 cal. kyr BP and showed minima at 5.9 and 4.1 cal. kyr BP. In spite of some discrepancy in short periods, this feature is consistent with that estimated from the assemblages of Ostracodas. δ 18 O value of benthic foraminifera of Nonionellina labradorica and Nonionella stella, alkenone production flux, and pollen assemblages could reflect annual-based temperature, which generally suggests that the climate was warmer at 6.0-4.2 cal. kyr BP, which could show the warmer environments at 6.0-5.0 cal. than expected from alkenone SST in early-midsummer. Overall, northward shift of the westerly jet, in association with a strengthened East Asian Summer Monsoon, could cause a relatively warm climate around 6.0-4.3 cal. kyr BP, when the Sannai-Maruyama site flourished. High food production density, by effective hansaibai (selective preservation or growth) in Castanea-and Aesculus-dominated forests, up to one sixth of the rice production density, could have supported high population density, resulting large community at the Sannai-Maruyama site. Cooling episode at 4.2 cal. kyr BP could have resulted in the decline of chestnut hansaibai, leading to the collapse of the site. Recent results from a compiled archeological site map suggested no large decline of the population but, instead, a dispersal to the surrounding area at 4.2 cal. kyr BP. It is consistent with ancestral population dynamics for the descendent from Jōmon people, in contrast to those from the immigrants from Far East Asia to the Japanese Archipelago with paddy rice cultivation technology after 2.9 cal. kyr BP, based on modern Japanese molecular sequences.

Climatic change and its relationship with human society in northern Japan since the mid-Holocene - Quantitative reconstruction of atmospheric and sea surface temperature -

“…The SST was reconstructed based upon the analysis of C37 alkenone. The major alkenone-producing coccolithophorid was Emiliania huxleyi in this area under both the Tsugaru and Oyashio currents (Hagino et al, 2005;Kawahata et al, 2017a;Kawahata, 2019). The major production period of E. huxleyi has been observed in satellite images in summer (June -August) (Takahashi et al, 1995), which is confirmed by the sediment trap experiment at Site MD01-2409 (41°33.8', 141°52.0'E) under the influences by the Tsugaru current ( Fig.…”

“…In Funka Bay, alkenone SSTs (ATs) showed definite cooling by 2-3°C at this event. Kawahata (2019) discussed the climatic mechanism behind the event based upon the environmental factors in Mutsu Bay, and concluded that southward shift of the westerly jet, in association with a weakened East Asian Summer Monsoon, could cause a relatively cool climate.…”

Application of Methods for a Morphological Analysis of the Femoral Diaphysis Based on Clinical CT Images to Prehistoric Human Bone: Comparison of Modern Japanese and Jomon Populations from Hegi Cave, Oita, Japan

“…This is consistent with previous findings showing that the linea aspera of the femur of an Initial Jomon man excavated from Futsukaichi cave (Futsukaichi city, Oita Prefecture, Japan), which is in the vicinity of Hegi cave, was not developed [ 36 ]. The period from 4,000 to 4,500 years ago, which was defined as the Late Jomon Period in the present study, was a time of decreasing temperatures in the Holocene world [ 21 ]. This was a time when it became difficult to obtain food, and many settlements in other parts of Japan were reported to have disappeared [ 20 ].…”

“…The Late Holocene is dated to the Late Jomon Period, while the other groups are roughly dated to the Initial/Early Jomon Period. In the Holocene, which began with the end of the Ice Age, the Late Holocene is the period during which temperatures dropped and many settlements disappeared [ 20 , 21 ]. Changes in the living environment may be reflected not only by comparisons between modern humans and the prehistoric remains excavated from Hegi cave but also differences in the ages of the prehistoric remains.…”

Foraminiferal Mn/Ca as Bottom‐Water Hypoxia Proxy: An Assessment of Nonionella stella in the Santa Barbara Basin, USA

“…N. stella is well established as indicator taxon for low‐oxygen conditions (e.g., Bernhard et al., 1997). Nevertheless, it has been rarely used for geochemistry‐based paleoceanographic reconstructions (Altenbach et al., 2012; Kawahata, 2019) and its TE composition has not previously been studied. Here we pair in a multi‐technique approach SIMS in situ TE analyses, to determine the concentration of Mn, Mg and Sr, with state‐of‐the‐art synchrotron radiation‐based scanning XRF (X‐ray fluorescence) multilength scale imaging, to map the Mn and Ca distribution in selected foraminiferal tests in high resolution.…”