日本地球惑星科学連合2019年大会

講演情報

[J] ポスター発表

セッション記号 M (領域外・複数領域) » M-IS ジョイント

[M-IS19] 古気候・古海洋変動

2019年5月30日(木) 17:15 〜 18:30 ポスター会場 (幕張メッセ国際展示場 8ホール)

コンビーナ:岡崎 裕典(九州大学大学院理学研究院地球惑星科学部門)、岡 顕(東京大学大気海洋研究所)、加 三千宣(愛媛大学沿岸環境科学研究センター)、長谷川 精(高知大学理工学部)

[MIS19-P14] モンゴル南西部オログ湖堆積物から復元される最終氷期~完新世の古環境変動とホモ・サピエンス定着との関係性

*長谷川 精1野間 七瀬1勝田 長貴2村山 雅史3田村 亨4出穂 雅実5イチノロフ N.6ダワドルジ D.7長谷部 徳子8笹岡 美穂9岩井 雅夫9 (1.高知大学理工学部、2.岐阜大学教育学部、3.高知大学農林海洋学部、4.産業総合研究所地質情報研究部門、5.首都大学東京人文社会学部、6.モンゴル科学アカデミー、7.モンゴル国立大学、8.金沢大学環日本海域環境研究センター、9.高知大学海洋コア総合研究センター)

キーワード:湖底堆積物、塩湖、古環境変動、ダンスガードイベント、ホモ・サピエンス、上部旧石器時代初期および前期

An aim of the present study is to understand detailed paleoenvironmental changes in Mongolia, situated at a key crossroad for Homo sapiens's migration between central, eastern, and northern Asia during the Initial and Early Upper Paleolithic (IUP-EUP). Available archaeological evidences have suggested the emergence of IUP at around ca. 45-40 ka (e.g., Zwyns et al., 2014; Rybin et al., 2016; Izuho et al., 2018). However, yet the paleoenvironmental changes of this period in Mongolia is largely unclear, preventing us to understand whether the possible environmental changes were significant as a major driving forth for modern human’s lifeway.

In this paper, we present a new record of paleoenvironmental changes in southwestern Mongolia during MIS 3. In January 2017, we took two parallel cores (OROG01, 24 m; OROG02, 21 m) from Orog Lake, a shallow saline lake located in northwestern margin of Gobi Desert. The high-resolution major and minor element composition changes were obtained using μXRF core scanner (Cox, Itrax) at Center for Advanced Marine Core Research, Kochi University. Based on the preliminary results of OSL and 14C age dating, basal age of sediment core OROG01 yielded ca. 38 ±4 ka, nearly accordant with the basal age of ~45 ka reported in the previous study (Yu et al., 2019). On the basis of our high-resolution elemental composition data, in conjunction with previous sedimentological and palynological data (Yu et al., 2019), the paleoenvironments of southwestern Mongolia were more humid with higher lake levels during MIS 3 than Holocene. Our results also suggest periodic and higher amplitude paleoenvironmental changes in this region, which likely correspond to Dansgaard-Oeschger events. This new record would allow us to discuss potential relationship between paleoenvironmental changes and ecosystem changes in Mongolia during the IUP-EUP.