The Quaternary Research (daiyonki-kenkyu)最新文献

{"title":"U-Series Ages for Solitary Coral Species from the Middle Pleistocene Kunosan Formation in the Udo Hills, Shizuoka, Central Japan","authors":"A. Kitamura, A. Omura, E. Tominaga, K. Kameo, Masakazu Nara","doi":"10.4116/JAQUA.44.177","DOIUrl":"https://doi.org/10.4116/JAQUA.44.177","url":null,"abstract":"The middle Pleistocene Kunosan Formation is distributed in the Udo Hills (Shizuoka, central Japan) that was tectonically uplifted about 300m during the late Quaternary. The formation consists of about 200-m-thick of coarse-grained fan-delta deposits. The thorium-230 age of a species of solitary coral from the Kunosan Formation in the eastern Udo Hills (Muramatsu Gravel-Silt Member) is 176.5+3.7-3.6ka (error is 1σ). This radiometric age means that the Kunosan Formation was deposited during marine isotope stage 6.5. This interpretation is consistent with previously published chronologic information for the middle and upper Pleistocene in the Udo Hills.","PeriodicalId":106287,"journal":{"name":"The Quaternary Research (daiyonki-kenkyu)","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121416148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Paleoclimatic Changes during the Last 6.5 Million Years Based on the Particle Density Variation of Lake Baikal Sediments","authors":"N. Iwamoto, M. Kawaguchi, Y. Inouchi","doi":"10.4116/JAQUA.44.79","DOIUrl":"https://doi.org/10.4116/JAQUA.44.79","url":null,"abstract":"バイカル湖で1998年に掘削されたコア(BDP 98)の粒子密度プロファイルより,バイカル湖の過去約650万年間の珪藻生産量と気候変動を推定した.BDP 98コアの粒子密度は,堆積物中の珪藻殻濃度を強く反映している.一般に,温暖期には珪藻殻に富んだ堆積物,寒冷期にはほとんど珪藻殻を含まない細粒な粘土質堆積物が堆積する.これらのことを用いて,バイカル湖周辺域の気候変遷史の復元を試みた.BDP 98コアの密度測定結果より,バイカル湖周辺域の過去650万年間の気候変遷は大きく3つの時代に分けることができる.その最新期にあたる第四紀の粒子密度は,海洋コアの底生有孔虫の酸素同位体比の変動パターンと,数万年スケールでよく類似している.そのため,この時代の堆積年代・堆積速度は,BDP 98コアの粒子密度プロファイルを酸素同位体比曲線に対比することにより推定できる.BDP 98コアの粒子密度は,堆積物中の珪藻殻濃度を強く反映していることから,粒子密度より生物源シリカ含有率を推定できる.これらの堆積速度と生物源シリカ含有率から,珪藻生産量(生物源シリカフラックス)を推定し,その増減を気候変動のプロクシーとした.その結果,汎世界的な気候変動との同調性が認識されるとともに,バイカル湖特有の気候イベントのいくつかが見いだされた.","PeriodicalId":106287,"journal":{"name":"The Quaternary Research (daiyonki-kenkyu)","volume":"178 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124418944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Discovery of a Buried Wood Piece and its 14C Date in the Esaoman-Tottabetsu Valley, Hidaka Mountains, Hokkaido, Japan","authors":"T. Sawagaki, K. Hirakawa, Shogo Iwasaki, Shogo Iwasaki","doi":"10.4116/JAQUA.44.117","DOIUrl":"https://doi.org/10.4116/JAQUA.44.117","url":null,"abstract":"日高山脈北部のエサオマントッタベツ川において,最終氷期後期の氷河最拡大を示すターミナルモレーン付近の支沢の堆積物中に,木材遺体が埋没しているのを発見した.埋木片は,マツ属単維管束亜属の1種(Pinus subgen. Haploxylon sp.)であると同定され,14C年代測定の結果,12.3cal kaが得られた.この年代は,晩氷期の一時的な寒冷期(新ドリアス期)に相当し,北海道の平野部においてグイマツとハイマツが高率に出現する剣淵亜氷期に相当する.埋木片を採取した堆積物は,氷河底ティルの可能性が考えられるダイアミクトンを覆って押出し状に堆積しており,斜面崩壊堆積物に取り込まれながら,採取地点まで流下したものであると考えられる.本資料の樹種同定結果と年代値は,晩氷期～後氷期の温暖化傾向にある時期の一時的な寒冷期における山地植生や山地斜面の発達史を考える上で,有用な資料となることが期待される.","PeriodicalId":106287,"journal":{"name":"The Quaternary Research (daiyonki-kenkyu)","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127078682","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of “24ka Nakanojo Mud Flow” Event on the Fluvial Landform Development in Nakanojo Basin, Central Japan","authors":"Hidetsugu Yoshida, T. Sugai","doi":"10.4116/JAQUA.44.1","DOIUrl":"https://doi.org/10.4116/JAQUA.44.1","url":null,"abstract":"後期更新世以降の中之条盆地の地形発達史を復元し,約2.4万年前に発生した浅間火山の大規模山体崩壊に由来する中之条泥流の流下・堆積過程と,それによる地形変化を検討した.中之条泥流は,既存の堆積段丘面にのりあげて中之条面を形成した.泥流堆積物の層厚および堆積頂面高度は,吾妻川の攻撃斜面側で大きく,中之条面には流れ山が分布する.中之条泥流は,岩屑なだれとしての性質を保持した状態で幅の狭い谷中を流下後,谷幅が広がる盆地に流入し,急激に減速したと考えられる.その結果,大量の堆積が生じ,当時の河床から約20～30mの比高を有していた段丘面に,中之条泥流がのりあげたと推定される.中之条泥流の堆積後,現在に至るまで吾妻川では侵食作用が卓越してきた.これらのことから,中之条泥流イベントは,完新世に至るまで河床変動をコントロールしてきたと考えられる.","PeriodicalId":106287,"journal":{"name":"The Quaternary Research (daiyonki-kenkyu)","volume":"233 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122542356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Depositional Process and Landform of the Kiso River Delta, Reconstructed from Grain Size Distributions, and Accumulation Rate of Sediment Cores","authors":"M. Yamaguchi, T. Sugai, O. Fujiwara, H. Ohmori, T. Kamataki, Y. Sugiyama","doi":"10.4116/JAQUA.44.37","DOIUrl":"https://doi.org/10.4116/JAQUA.44.37","url":null,"abstract":"木曽川デルタで掘削された2本のボーリングコア(海津コアと大山田コア)の粒度組成から,デルタの微地形を復元した.さらに,堆積速度との関係を検討した.両コアは,プロデルタ,デルタフロントスロープ,デルタフロントプラットフォームを構成する典型的なデルタのサクセッションを示す.しかし,粒度組成と堆積速度は両地点の微地形の違いを反映して異なっている.プロデルタ堆積物は,浮流物質のみからなる海津コアに対して,養老山地に近い大山田コアは支流からの土砂供給を示す二峰性の粒度分布をもった堆積物を挾在する.堆積速度は,前者では小さく(1.4～3.7mm/yr),後者で大きい(1.9～4.6mm/yr).デルタフロントスロープ堆積物は,海津コアで典型的な上方粗粒化傾向を示す一方,大山田コアでは粗粒で淘汰がよい堆積物や,二峰性の粒度分布を示す堆積物を挾在する.これは,海津コアが河川からの土砂が集中するローブの中心付近に位置していたのに対して,大山田コアは河川フラックスの小さいローブの外縁付近に位置し,相対的に波浪や沿岸流などで再配置された淘汰のよい堆積物が堆積する割合が高かったためと推定される.堆積速度は前者で大きく(～55.8mm/yr),後者で小さい(～12.6mm/yr).","PeriodicalId":106287,"journal":{"name":"The Quaternary Research (daiyonki-kenkyu)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124501164","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fossil Pollen Assemblages from Marine Terrace Deposits of Oxygen Isotope Stage 7.3 in Harima Plane, Hyogo Prefecture, Western Japan","authors":"M. Matsushita, Hiroshi P. Sato, Shigehiro Katoh, M. Hyodo","doi":"10.4116/JAQUA.44.31","DOIUrl":"https://doi.org/10.4116/JAQUA.44.31","url":null,"abstract":"兵庫県,播磨平野東部の加古川市都台の海成段丘堆積物は,珪藻および火山灰分析によって海洋酸素同位体ステニジ7.3の海進期ピーク(約215ka)に相当することが示されており,重要な地磁気エクスカーションも見いだされている.本研究では,この高海面期堆積物について花粉分析を実施したので報告する.海成堆積物中に見られる花粉組成から,海洋酸素同位体ステージ7.3の最暖期の都台周辺には,ブナ属,コナラ属コナラ亜属を主とする落葉広葉樹林とマツ林が成立していたと考えられる.この海成段丘堆積物は,挾在する火山灰の対比から大阪層群Ma11(2)に相当しており,大阪湾での海底ボーリング堆積物のMa11海成粘土層の花粉組成と比較すると,マツ属複維管束亜属とブナ属が卓越し,コナラ属アカガシ亜属などの暖帯要素が少ないことが共通していた.しかし,Ma11層の特徴的属であるとされているトガサワラ属は検出されなかった.そして,都台の東方に隣接する神戸市垂水区の高塚山粘土層(Ma9層,海洋酸素同位体ステージ11)の海進期堆積物中では,常緑広葉樹林の構成種であるコナラ属アカガシ亜属花粉等が高率で出現する.このように中期更新世の間氷期の中でも,優占する種群に違いが見られ,海洋酸素同位体ステージ7.3の海進期(Ma11(2)層堆積時)はMa9層堆積時より,冷涼であったといえる.","PeriodicalId":106287,"journal":{"name":"The Quaternary Research (daiyonki-kenkyu)","volume":"116 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121322413","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stratigraphy and Ages of Aira Caldera Deposits in Shinjima (Moeshima), Kagoshima Prefecture, West Japan","authors":"S. Kameyama, S. Shimoyama, Shunsuke Miyabe, Y. Miyata, T. Sugiyama, H. Iwano, T. Danhara, K. Endo, A. Matsukuma","doi":"10.4116/JAQUA.44.15","DOIUrl":"https://doi.org/10.4116/JAQUA.44.15","url":null,"abstract":"現在の鹿児島湾奥部は,約25,000yrs BPの大噴火で生じた姶良カルデラにあたる.新島(燃島)はカルデラのほぼ中央部に位置し,1779～1780年の「安永の噴火」によってカルデラ海底から隆起したため,姶良カルデラでの環境変遷を記録している重要な島である.しかし,これまでの研究には,層序における不一致や矛盾があった.地質の再調査と年代測定の結果,新島の地質は下位より州崎軽石層,燃島シルト層,燃島シラス層,燃島貝層,新島シラス層,降下火山灰層,それに表土からなることが判明した.岩相と年代の一致から,南海岸露頭のシルトは北海岸の燃島シルト層に同定され,約14,600yrs BPから7,800yrs BPの間に形成された.燃島シルト層直下の南海岸の厚い軽石層を州崎軽石と命名した.その形成時期は,14C年代で約14,600yrs BP以前,フィッショントラック年代では約16±4kaである.一方,燃島シルト層直上の燃島シラスの形成時期は,約7,800yrs BPから6,000yrs BPまでの間である.州崎軽石と燃島シラスは,ともに姶良カルデラ湖底での水中爆発を起源としている.燃島シラスを噴出した水中爆発は,それ以前の地層を変形・侵食し,それ以後の地層との間の不整合面を形成した.姶良カルデラが淡水環境から海水環境に変わった時期は,11,700yrs BPから11,000yrs BPの海面上昇期にあたる.カルデラ壁の南側が開いていたので,海面上昇により姶良カルデラの外側と内側が同時に海水環境となった.燃島貝層は約6,000yrs BPから約2,300yrs BPの期間に形成された.燃島貝層からその直上の新島シラス層に見られる外洋種化石群から内湾種化石群への漸移は,約2,300yrs BP以降に桜島の急速肥大などによって,湾奥がより閉鎖的になったことを示唆する.","PeriodicalId":106287,"journal":{"name":"The Quaternary Research (daiyonki-kenkyu)","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125340826","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Holocene Sedimentary Environments and Relative Sea Levels at a Site along the Coast of Lake Tofutsu in the Eastern Part of Hokkaido, Japan","authors":"Hiroshi P. Sato, I. Matsuda, Shigehiro Katoh, Takashi Matsubara","doi":"10.4116/JAQUA.43.447","DOIUrl":"https://doi.org/10.4116/JAQUA.43.447","url":null,"abstract":"北海道東部,涛沸湖沿岸において,貝類遺骸を多数含有する完新統の堆積物コアを採取した.貝類遺骸群集中には,現在本州以南に分布するウネナシトマヤガイ(Tropegium(Neotrapezium)liratum)が含まれ,その14C年代測定の結果から約3,300yrs BPの生息記録が得られた.堆積物中のイオウ含有量,珪藻遺骸群集,そして貝類遺骸群集にもとづき堆積環境を推定した.堆積物中のイオウ含有量と珪藻遺骸群集を指標に,認定された海成層の上限(マリンリミット)は,標高+0.30mであり,貝類遺骸群集が示す上限(標高-0.23m)に比べて高く,その間には0.53mの差異が認められた.干潟に特徴的な珪藻の環境指標種と貝類遺骸の出現から,相対的海水準高度として標高-1.40m(3,320±60yrs BP)と-0.23m(1,290±60yrs BP)が推定された.この旧海水準記録は,これまでオホーツク海沿岸の低地から報告された完新世後期の海水準に比べて低く,このことは当該調査地点の相対的な沈降を示すと考えられる.","PeriodicalId":106287,"journal":{"name":"The Quaternary Research (daiyonki-kenkyu)","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115049629","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Phytolith Records from Tephra-soil Sequence since the Last Interglacial in the Southern Ishikari Lowland, Hokkaido, Japan","authors":"T. Sase, K. Yamagata, M. Hosono, J. Kimura","doi":"10.4116/JAQUA.43.389","DOIUrl":"https://doi.org/10.4116/JAQUA.43.389","url":null,"abstract":"","PeriodicalId":106287,"journal":{"name":"The Quaternary Research (daiyonki-kenkyu)","volume":"104 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125566252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Last Interglacial Sea Level Changes Deduced from Coral Reef Terraces in Southwest Bohol, Central Philippines","authors":"C. Ringor, A. Omura, Y. Maeda","doi":"10.4116/JAQUA.43.401","DOIUrl":"https://doi.org/10.4116/JAQUA.43.401","url":null,"abstract":"High precision α-spectrometric U-series dates for fossil corals from raised marine terraces in Pamilacan Island and from the neighboring Panglao Island and Punta Cruz in southwest Bohol were combined with previous data to re-examine the sea level history during the Last Interglacial and its implications to the tectonic setting of the area. Hermatypic corals were collected at elevations between 3-6m, 9-13m, and 20-27m apmsl (above present mean sea level) from three successive terraces in Pamilacan which have maximum elevations of 6m, 13m, and 27m apmsl. The dates of these corals cluster within 79-83ky, 101-108ky, and 122-131ky (from lowest to highest terrace) which correspond respectively to the marine isotope stages (MIS) 5a, 5c, and 5e. A constant rate of tectonic uplift ranging from 0.18-0.21m/ky in the past 125ky was estimated based on the published mean sea level data of 3-6m apmsl during MIS 5e. Using these local uplift rates, the respective paleo-sea levels during 5c (105ky) and 5a (82ky) are calculated to be 9-11m and 6-9m below present, which are consistent with uplift-corrected reef data estimates from Haiti, Barbados, and Huon Peninsula. The 5a paleo-sea level also coincides closely with the results from the submerged reefs of the tectonically stable Florida margin. The substantial agreement between the Pamilacan paleo-sea levels with those from different localities worldwide support the assumption of a constant uplift rate in the past 125ky. In contrast, the altitude of the sea level indicators correlated to the MIS 5e in Panglao and Punta Cruz are much lower, ≥12m apmsl, while that of 5c are ca. 5-6m apmsl. Minimum local uplift rates since MIS 5e ranges from 0.06-0.09m/ky, three times lower than that of Pamilacan. The estimated mean sea level during 5c is only a few meters (ca. 3m) below present indicating that uplift is not constant. Significant variation in the elevations of contemporaneous terraces at the three neighboring islands may have been greatly influenced by localized tectonic activity which puts the reported relative vertical stability of the region into question.","PeriodicalId":106287,"journal":{"name":"The Quaternary Research (daiyonki-kenkyu)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125481324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}