Antarctic Circumpolar Current Fluctuation in the Late Neogene: constraint from sediment wave on the Conrad Rise, Indian Sector of the Southern Ocean

第3回極域科学シンポジウム　横断セッション「海・陸・氷床から探る後期新生代の南極寒冷圏環境変動」11月26日（月） 国立国語研究所 ２階講

Physical and chemical weathering properties of till deposits in the Sør Rondane Mountains, Dronning Maud Land (II)

第6回極域科学シンポジウム[OG] 地圏11月16日（月）　国立極地研究所３階セミナー

ヒガシ ドロンイングモードランド,セール・ロンダーネ サンチ チガク チョウサタイ ホウコク 20112012(JARE-53)

第53次日本南極地域観測隊(JARE-53)夏隊の一部は,2011-2012年の夏期に,東ドロンイングモードランドのセール・ロンダーネ山地において地形・測地調査を実施した.また,この調査はBelgian Antarctic Research Expedition (BELARE)とInternational Polar Foundation(IPF)のサポートによって実施された.本調査のメンバー構成は,地形調査担当3名,測地担当1名,およびフィールドアシスタント1名である.南極への移動経路は往復路ともにドロンイングモードランド航空ネットワーク(DROMLAN)を利用し,空路ケープタウンからノボラザレフスカヤ基地滑走路を経由して現地入りした.調査地域はセール・ロンダーネ山地の西部および中部とした.本稿では調査,設営,気象をはじめとする本調査隊の行動全般について報告する.Geomorphologic and geodetic field surveys were carried out in the Sør Rondane Mountains, East Dronning Maud Land, Antarctica, during the 2011-2012 summer season as part of the 53rd Japanese Antarctic Research Expedition (JARE-53). The field party consisted of three geomorphologists, one geodesist, and one field assistant. The expedition was supported by the Belgian Antarctic Research Expedition (BELARE) and the International Polar Foundation (IPF). Dronning Maud Land Air Network (DROMLAN) provided air transport from Cape Town, South Africa to the Sør Rondane Mountains via Novolazarevskaya Airbase. The survey areas were the central and western parts of the Sør Rondane Mountains. This report summarizes the field expedition in terms of operations, logistics, and weather records

Climatically driven changes in the supply of terrigenous sediment to the East China Sea

Author Posting. © American Geophysical Union, 2018. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry, Geophysics, Geosystems 19 (2018): 2463-2477, doi:10.1029/2017GC007339.We examine the paleoceanographic record over the last ∼400 kyr derived from major, trace, and rare earth elements in bulk sediment from two sites in the East China Sea drilled during Integrated Ocean Drilling Program Expedition 346. We use multivariate statistical partitioning techniques (Q‐mode factor analysis, multiple linear regression) to identify and quantify five crustal source components (Upper Continental Crust (UCC), Luochuan Loess, Xiashu Loess, Southern Japanese Islands, Kyushu Volcanics), and model their mass accumulation rates (MARs). UCC (35–79% of terrigenous contribution) and Luochuan Loess (16–55% contribution) are the most abundant end‐members through time, while Xiashu Loess, Southern Japanese Islands, and Kyushu Volcanics (1–22% contribution) are the lowest in abundance when present. Cycles in UCC and Luochuan Loess MARs may indicate continental and loess‐like material transported by major rivers into the Okinawa Trough. Increases in sea level and grain size proxy (e.g., SiO2/Al2O3) are coincident with increased flux of Southern Japanese Islands, indicating localized sediment supply from Japan. Increases in total terrigenous MAR precede minimum relative sea levels by several thousand years and may indicate remobilization of continental shelf material. Changes in the relative contribution of these end‐members are decoupled from total MAR, indicating compositional changes in the sediment are distinct from accumulation rate changes but may be linked to variations in sea level, riverine and eolian fluxes, and shelf‐bypass processes over glacial‐interglacials, complicating accurate monsoon reconstructions from fluvial dominated sediment.U.S. National Science Foundation Grant Numbers: NSF‐EAR1434175, NSF‐EAR1433665, NSF‐EAR143413

Antarctic Cryosphere Evolution Project (AnCEP): New IODP proposal for transect drilling in the Southern Ocean

第3回極域科学シンポジウム　横断セッション「海・陸・氷床から探る後期新生代の南極寒冷圏環境変動」11月26日（月） 国立国語研究所 ２階講

Depositional architecture, provenance, and tectonic/eustatic modulation of Miocene submarine fans in the Shikoku Basin: Results from Nankai Trough Seismogenic Zone Experiment

Seismostratigraphy, coring, and logging while drilling during Integrated Ocean Drilling Program Expeditions 319, 322, and 333 (Sites C0011/C0012) show three Miocene submarine fans in the NE Shikoku Basin, with broadly coeval deposits at Ocean Drilling Program Site 1177 and Deep Sea Drilling Project Site 297 (NW Shikoku Basin). The sediment dispersal patterns have major implications for paleogeographies at that time. The oldest, finer-grained (Kyushu) fan has sheet-like geometry; quartz-rich flows were fed mostly from an ancestral landmass in the East China Sea. During prolonged hemipelagic mud deposition at C0011-C0012 (~12.2 to 9.1 Ma), sand supply continued at Sites 1177 and 297. Sand delivery to much of the Shikoku Basin halted during a phase of sinistral strike slip to oblique plate motion, after which the Daiichi Zenisu Fan (~9.1 to 8.0 Ma) was fed by submarine channels. The youngest fan (Daini Zenisu; ~8.0 to 7.6 Ma) has sheet-like geometry with thick-bedded, coarse-grained pumiceous sandstones. The pumice fragments were fed from a mixed provenance that included the collision zone of the Izu-Bonin and Honshu Arcs. The shift from channelized to sheet-like flows was favored by renewal of relatively rapid northward subduction, which accentuated the trench as a bathymetric depression. Increased sand supply appears to correlate with long-term eustatic lowstands of sea level. The stratigraphic position and 3-D geometry of the sandbodies have important implications for subduction-related processes, including the potential for focused fluid flow and fluid overpressures above and below the plate boundary fault: In sheet-like sands, pathways for fluid flow have greater horizontal permeability compared with those in channel sands

Preparation for deep sea drilling proposal in the Indian Sector of the Southern Ocean: Conrad Rise and off Enderby Land

第2回極域科学シンポジウム/第31回極域地学シンポジウム 11月16日（水） 国立国語研究所　2階フロ