Language：Japanese   Publisher：岩波書店  

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Language：Japanese   Publisher：愛媛大学教育学部  

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Language：Japanese   Publisher：愛媛大学教育学部  

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Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)   Publisher：公益社団法人 日本地理学会  

In this paper, authors report a practice of ESD education done in cooperation of high school and university which made the Minamata disease a subject. Minamata disease incident happened in a small local town MInamata. Authors made high school students understand the incident in geographical context. Reading documents and contour map, the students could recognize precise and concrete figure of Minamata area. Students acquired the positive attitude to settle the problem from this study.

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Language：Japanese   Publisher：愛媛大学教育学部  

CiNii Books

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Publisher：The Association of Japanese Geographers  

“Guerrilla heavy rainfall” occurred in Matsuyama on July 9, 2015. Flooding on the road and houses occurred very locally in the city. The feature of the flood is made clear and the background of flood occurrence is considered from the point of the land-use change.

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Language：Japanese   Publisher：日本地形学連合  

CiNii Books

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Publisher：The Association of Japanese Geographers  

香川県西部・三豊地域中部には財田川と柞田川が流れ、観音寺市街地付近で瀬戸内海・燧灘に注ぐ。平成16年の台風による水災害は、多くの河川流域で集中豪雨と土石流、氾濫をもたらすとともに、数次にわたって高潮災害を伴う複合災害であった。当地でも中小河川における氾濫と高潮の被災を受けて、大きな混乱を生じた。 本報告では、1年間に集中して大きな被害をもたらした平成16年の風水害と避難とのかかわりを述べる。我が国で最も面積の狭小な香川県ですら、その東西では被災の様相が全く異なっていた。とくに、台風に係わる水災害では、その被災区域と、地形環境との関係が深い。本報告では、国土地理院所蔵の５ｍメッシュDEMから地盤高デジタルマップを作成すると共に微地形との関わりを検討する。また、市街地と中上流部での被災の差異、地域の人々が水害の教訓をどのように認識しているかについても報告する。

DOI： 10.14866/ajg.2013s.0_108

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Language：Japanese   Publisher：愛媛大学教育学部  

CiNii Books

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Language：Japanese   Publisher：愛媛大学教育学部  

CiNii Books

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Language：Japanese   Publisher：人文地理学会  

DEMを用いた標高マップと新旧地形図から地形環境を考察し、土地条件図、ハザードマップとの整合と解析を行う。

DOI： 10.11518/hgeog.2012.0.68.0

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Language：Japanese   Publisher：The Association of Japanese Geographers  

Characteristics of acid sulfate soil and landform evolutions were studied in the coastal plain around Nakhon Si Thammarat, southern Thailand. The coastal plain is characterized as the low and flat coastal plain with several rows of beach ridges. Broad swampy area develops behind the distinct row of beach ridge on which the urban area of Nakhon Si Thammarat is located. Acid sulfate soil mostly develops in the swampy area behind the distinct beach ridge. Surface geology of the region were studied at about 50 sites with a hand auger. Six soil samples in the region were collected and measured for PH.The strong acid sulfate soil was measured in the horizons of peat layer which develops widely behind the long and distinct beach ridge. No acid sulfate soil can be seen in the outer area of the beach ridge where the land was extended after the middle Holocene transgression.From the results, it is clarified that acid sulfate soil occupies in the distinct area as bog which is enclosed with old beach ridges. The bog was former mangrove swamp in the period of middle Holocene, and sulfidic material accumulated in the time. After the culmination of the middle Holocene transgression, the younger beach ridge and coastal plain developped towards the east. The vegetation of the inner region changed to the secondary forest (such as salt grass and Melaleuca leucadendron) under reducing of salinity, and the sediment of secondary forest deposited on the sulfidic material of the mangrove peat. Consequently, environment of area change again by fresh water sediment deposited on the surface as thin topsoil.

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Language：Japanese   Publisher：日本森林学会  

DOI： 10.11519/jfsc.119.0.495.0

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Language：Japanese   Publisher：The Association of Japanese Geographers  

<BR>はじめに<BR> ベトナム南部に広がるメコンデルタの形成過程に関しては、メコン川本流付近の堆積作用が卓越する地域でその概略が明らかにされているものの（Nguyen et al. 2000, Ta et al. 2002）、土砂供給量が相対的に少ない周辺地域の地形発達に関しては不明な点が多い。一方、ベトナム南部で現在大面積のマングローブ林がみられるのは、南端のカマウ岬とホーチミン市南東部のカンザー地区のみである。マングローブ林は土砂供給量が少ない立地ではマングローブ泥炭を自ら生産・蓄積することでその立地を形成・維持することが知られている（藤本 2003）。そのため、熱帯地域におけるデルタの形成過程を論じる場合には、土砂供給に伴う地形発達と共に、マングローブ林を始めとする低湿地林の立地変動を明らかにする必要がある。また、マングローブ林は中等潮位付近から最高高潮位の間にのみ成立するため、マングローブ泥炭の存在は、当時の海水準を復元する直接的な指標となり得る。<BR> そこで本研究では、これまで詳細な地形発達情報が得られていないメコンデルタ北部とその北東側に隣接するドンナイ川下流低地を対象地域とし、特にマングローブ泥炭層の分布に着目して、後氷期海進以降の地形発達を海水準変動およびマングローブ林の立地変動と共に明らかにすることを目的とする。<BR><BR>地域概観<BR> 研究対象地域は、メコンデルタ北部のロンアン（Long An）省およびホーチミン市を中心とする地域である。本地域はメコン本流から離れているため供給土砂量は比較的少ない。そのためロンアン省の一部には、表層付近までマングローブ堆積物が露出し、硫酸酸性塩土壌が形成され、ほとんど土地利用がなされていない低湿地がみられる。一方、ドンナイ川は、ホーチミン市南東部カンザー地区に小規模デルタを形成しており、現在は４万haに上るマングローブ林が広がる。このマングローブ林はベトナム戦争時に米軍による枯葉剤攻撃でほぼ壊滅状態となったが、その後ベトナム人自身による積極的な植林活動によりほぼ全域で緑が回復し、現在ではユネスコによる生態系保全地域に指定され、世界的にも有名なマングローブ地帯となっている。<BR><BR>研究方法<BR> メコンデルタ北部で25地点、ドンナイ川デルタ（支流のサイゴン川低地を含む）で17地点の計44地点でハンドボーリングを行い表層地質を明らかにすると共に、<SUP>14</SUP>Ｃ年代測定試料を採取した。年代試料はボーリングコア中から採取された木片および植物遺体で、計28点の年代値を得た。<BR> 調査地点の標高は、カシミール３Ｄを用いてダウンロードしたランドサット地形データ（SRTM）を用いて推定した。但し、本地域のSRTMデータは約90ｍメッシュのもので、また森林地帯ではその範囲の平均樹高が計測されるため、標高の推定は農耕地等の周辺が開けた地点のみで行った。<BR><BR>結果<BR> 調査地域内における沖積低地の地盤高は、河道沿いを除き+1ｍ前後と極めて低い。マングローブ泥炭の分布が確認されたのは、現海岸線から50～80km内陸側で、メコン川とその北側のバンコータイ（Vam Co Tay）川、およびバンコードン（Vam Co Dong）川の後背湿地である。マングローブ泥炭層の形成時期は7000～6000 cal BPで、いずれの地点も層厚１ｍ前後のシルト～粘土層に覆われる。これらの事実から、7000～6000 cal BPには上記地域に<I>Rhizophora</I>を主体とするマングローブ林が広がっており、当時の海水準は現海水準をやや下回っていたものと推定される。その後はデルタの前進とそれに伴う土砂供給で徐々に地盤高を増し、他のマングローブ種の優占林分へと遷移した後、淡水環境へと変化したと考えられる。6000 cal BP以降、メコンデルタ北部では<I>Rhizophora</I>が優占するマングローブ林はほとんど形成されなかった。一方、カンザー地区では層厚0.5～1.2ｍの粘土層に覆われて、マングローブ泥炭層が比較的広範囲に分布する。その形成年代は1300～400 cal BPを示し、そのほとんどは600 cal BP以降に形成された比較的新しいものであることが明らかになった。

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Language：Japanese   Publisher：日本地形学連合  

CiNii Books

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Language：Japanese  

DOI： 10.14866/ajg.2005f.0.64.0

CiNii Books

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Publisher：The Association of Japanese Geographers  

はじめに<BR>沖積低地は後氷期の急激な海面上昇時に形成された内湾を徐々に埋積することによって形成された堆積地形である。本研究では、矢作川下流低地を事例として完新世の地形発達に伴い貯留された土砂量および炭素量を、各層序毎に絶対量（質量）として明らかにすることを目的とする。<BR>沖積平野の埋積土砂量については、これまで「体積」として議論されることはあったものの、「質量」として捕らえられることはなかった。沖積層は、砂層、粘土層、泥炭層など多様な地層から構成される上、孔隙や間隙水を含んでおり、蓄積土砂量を各層序毎に定量的に比較するためには、これらを除いた質量として把握する必要がある。そのためには、不攪乱コアを深深度まで採取し、各層序の体積と共に、その容積重も明らかにしなければならない。各層序の体積は、ボーリング資料等で推定された各層序分布状況に基き、GIS３D解析ソフトを用いて推定する。<BR>沖積低地は氷期・間氷期サイクルの中でみると、後氷期における一時的な物質蓄積の場として機能しており、地球規模の物質循環の中で何らかの重要な役割を担っているものと考えられる。しかし、沖積平野研究は、未だに地形発達史研究に留まっており、地球規模での物質循環の中での役割についての評価は何らなされていない。沖積平野の地形発達過程を地球環境変動に伴う受動的な変化として捕らえるばかりでなく、その過程で発揮されてきた炭素蓄積機能を評価することにより、地球環境変動に対して能動的に影響を与える環境要素として再評価することが可能となる。なお、本研究は平成13_から_15年度科学研究費補助金（基盤研究(A)(1)、課題番号：13308004、研究代表者：藤本 潔）によって実施した。<BR>研究方法<BR>１）既存ボーリング資料を収集する。<BR>２）地表面高度、上部砂層上限高度、中部粘土層上限高度、中部粘土層下限高度、および下部砂層下限高度のデータベースをExcel上に作成する。<BR>３）ArcView 3D Analystを用い、地表面および各層序境界のグリッドサーフェスモデルを作成し、切り盛り解析によって各層序の体積計算を行う。<BR>４）２本の30ｍ不撹乱コアから得られた各層序の容積重および炭素含有率を用い、各層序中の蓄積土砂量および蓄積炭素量を質量として算出する。<BR>結果<BR>計算対象面積92.1km2における各層序の体積は、後背湿地堆積物からなる最上部層が1.96×10<SUP>8</SUP>ｍ<SUP>3</SUP>、上部砂層が7.16×10<SUP>8</SUP>ｍ<SUP>3</SUP>、中部粘土層が6.73×10<SUP>8</SUP>ｍ<SUP>3</SUP>、下部砂層が4.69×10<SUP>8</SUP>ｍ<SUP>3</SUP>で、全土砂体積に占める割合は、それぞれ9.5％、34.9％、32.8％、22.9％であるのに対し、質量から見た堆積土砂量は、それぞれ9.2％、38.9％、25.8％、26.1％と、細粒堆積物からなる最上部層および中部粘土層で体積比より小さく、上部砂層および下部砂層で大きくなる。<BR>蓄積炭素量は、それぞれ21.1％、5.7％、54.7％、18.5％で、体積比と比較すると、最上部層および中部粘土層で大きく、上部砂層および下部砂層で小さくなる。計算対象範囲内の蓄積炭素量は2.60×10<SUP>7</SUP>ｔと見積もられた。これは人間活動による年間化石炭素放出量（5.7×10<SUP>9</SUP>t）の約0.5％に達する。このことから、地球上の全沖積平野の堆積物中には、地球環境に何らかの影響を与えるに十分な量の炭素が閉じ込められている可能性が指摘できる。<BR>

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Language：English   Publisher：ARNOLD, HODDER HEADLINE PLC  

Shores of eastern Hokkaido rose by perhaps I m a few centuries ago. The uplifted area extended at least 50km along the southern Kuril Trench. It included the estuaries Akkeshi-ko and Hichirippu, on the Pacific coast, and Furen-ko and Onneto, which open to the Okhotsk Sea. At each estuary, intertidal and subtidal flats rose with respect to tide level; wetland plants colonized the emerging land; and peaty wetland deposits thereby covered mud and sand of the former flats. Previous work at Akkeshi-ko and Onneto showed that such emergence occurred at least three times in the past 3000 years. Volcanic-ash layers date the youngest emergence to the seventeenth century AD. New evidence from Akkeshi-ko, Hichirippu and Furen-ko clarifies the age and amount of this youngest emergence. Much of it probably dates from the century's middle decades. Some of the newly emerged land remained above high tides into the middle of the eighteenth century or later. The emergence in the last half of the seventeenth century probably exceeded 0.5m (inferred from stratigraphy and diatom palaeoecology) without far exceeding I m (estimated by comparing seventeenth- and eighteenth-century descriptions of Akkeshi-ko). The stratigraphy and palaeoecology of the emergence are better explained by tectonic uplift than by bay-mouth blockage, tidal-flat accretion or sea-level fall. Eastern Hokkaido needs occasional uplift, moreover, to help reconcile its raised marine terraces with its chronic twentieth-century subsidence. Because it took place above forearc mantle, eastern Hokkaido's seventeenth-century uplift probably lacks analogy with coseismic uplift that occurs above typical plate-boundary ruptures at subduction zones.

DOI： 10.1191/0959683604hl726rp

Web of Science

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Language：Japanese   Publisher：古今書院  

CiNii Books

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Language：Japanese   Publisher：日本地理学会  

DOI： 10.4157/grj.76.211

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Language：Japanese   Publisher：南山大学  

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Publisher：The Association of Japanese Geographers  

The author researched the Holocene sediments and geomorphic evolution of the Kumozu River lowlands using diatom analysis, electric conductivity, and <sup>14</sup>C dating, and discusses how the sedimentary environment changed during the late Holocene. The results are summarized as follows.<br> 1) After the Holocene transgression, sedimentation of upper marine sand in the southern lowlands proceeded to the northern lowlands and began to accumulate around 4, 800_??_4, 300 cal. BP. It is possible that the earlier river channel was in the southern lowlands and a shift of the river channel toward the north caused the difference in the depositional age.<br> 2) Three beach ridges finished forming before 2, 600 cal. BP, 1, 600 cal. BP, and the present, respectively. Beach ridge I, which formed before 2, 600 cal. BP, developed straight along the coast, while beach ridge II, which was formed before 1, 500 cal. BP, extended toward the sea around the river mouths. This suggests that the coastal lowlands was first dominated by waves, although it was dominated by the river after 2, 600 cal. BP and before 1, 500 cal. BP.<br> 3) Two flood sand layers are found in fluvial deposits. Flood sand I is relatively coarse and was deposited before 3, 000 cal. BP. The terrestrial environment was stable for a short period during 3, 000_??_2, 200 cal. BP. Flood sand II began to accumulate from 2, 200 cal. BP and it is finer and better sorted than flood sand I.<br> 4) Based on the increase in the thickness of the upper marine sand, the distribution of beach ridges, and sedimentation of the flood sand layers, it is assumed that the sediment supply increased after ca. 2, 000 cal. BP. This environmental change appears to be common to the Pacific coasts in central Japan.

DOI： 10.4157/grj.76.211

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Language：Japanese   Publisher：Association of Japanese Geographers  

The author researched the Holocene sediments and geomorphic evolution of the Kumozu River lowlands using diatom analysis, electric conductivity, and 14C dating, and discusses how the sedimentary environment changed during the late Holocene. The results are summarized as follows. 1) After the Holocene transgression, sedimentation of upper marine sand in the southern lowlands proceeded to the northern lowlands and began to accumulate around 4,800∼4,300 cal. BP. It is possible that the earlier river channel was in the southern lowlands and a shift of the river channel toward the north caused the difference in the depositional age. 2) Three beach ridges finished forming before 2,600 cal. BP, 1,600 cal. BP, and the present, respectively. Beach ridge I, which formed before 2,600 cal. BP, developed straight along the coast, while beach ridge II, which was formed before 1,500 cal: BP, extended toward the sea around the river mouths. This suggests that the coastal lowlands was first dominated by waves, although it was dominated by the river after 2,600 cal. BP and before 1,500 cal. BP. 3) Two flood sand layers are found in fluvial deposits. Flood sand I is relatively coarse and was deposited before 3,000 cal. BP. The terrestrial environment was stable for a short period during 3,000∼2,200 cal. BP. Flood sand II began to accumulate from 2,200 cal, BP and it is finer and better sorted than flood sand I. 4) Based on the increase in the thickness of the upper marine sand, the distribution of beach ridges, and sedimentation of the flood sand layers, it is assumed that the sediment supply increased after ca. 2,000 cal. BP. This environmental change appears to be common to the Pacific coasts in central Japan.

DOI： 10.4157/grj.76.211

Scopus

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Language：Japanese   Publisher：愛媛大学教育学部附属教育実践総合センター  

CiNii Books

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Language：English  

CiNii Books

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Language：Japanese  

CiNii Books

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Language：Japanese  

CiNii Books

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CiNii Books

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Other Link： http://id.nii.ac.jp/1141/00109786/

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Language：Japanese   Publisher：Japan Association for Quaternary Research  

The authors clarified the evolution of shallow buried valleys in the Nobi plain, especially in the archaeological sites of Kadomanuma and Mabikiyokote where these valleys typically develop.<br>The sites are located in the central Nobi plain near the boundary of the alluvial fan and the floodplain area; the buried shallow valleys dissect and develop on the well-developed sand layer which is related to the "upper sand layer" in the coastal region.<br>Based on close observation and the radiocarbon ages of sediments, the following results are clarified: The sand layer was dissected at ca. 3, 000-2, 400yrs BP, and shallow valleys were formed. These valleys were buried by ca. 2, 400-2, 200yrs BP.<br>In addition to these results, the authors clarified the geoenvironmental change in the region based on the geomorphic and geologic information from the surrounding areas. The geoenvironmental change in the region surrounding the Kadomanuma and Mabikiyokote sites is divided into the following four stages:<br>Stage I (3, 300-3, 000yrs BP): End of the deposition of the sand layer which is related to the "upper sand layer" in the coastal region.<br>Stage II (3, 000-2, 400yrs BP): Formation of shallow valleys on the sand layer. Flood sediments can be seen in the valleys, but the surrounding areas are in a stable condition that is characterized by humic or peaty sediments.<br>Stage III (2, 400-2, 200yrs BP): Deposition of sediments in the shallow valleys ceases at the end of this period. Environment of the surrounding area is relatively stable and there is less flooding.<br>Stage IV (2, 200yrs BP-): Active flooding occurs in the region, and the shallow valleys are buried completely.

DOI： 10.4116/jaqua.40.345

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Language：Japanese   Publisher：古今書院  

CiNii Books

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Language：Japanese   Publisher：名古屋大学  

It is known that Holocene peaty sediments are well developed in incised valleys at Pleistocene uplands in Japan. Those sediments have been studied for reconstruction of paleoenvironment. The author researched Nishi-Mikawa plain in central Japan, and got available sediments in an incised valley of Hekkai Upland. Three samples of the sediments were dated by AMS ^<14>C measurement. The result shows that accumulation of peat started around 3,100yr BP, and peaty silt and clay were deposited since 2,500yr BP. Diatom analysis was done for the samples and its result suggests that the site was affected by flowing water between 2,500 and 1,800yr BP. It is possible that the environmental change which was found in this valley was common throughout Nisi-Mikawa plain.

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Language：English   Publisher：ARNOLD, HODDER HEADLINE PLC  

The Shoalhaven River is one of the largest rivers on the south coast of New South Wales, and the deltaic-estuarine plains associated with its mouth represent a mature stage of infill of a barrier estuary. The stratigraphy of sediments from more than 60 drillholes from the plains indicates that the area has infilled during the mid-Holocene as a result of input of marine sands associated with a sand barrier on the high-energy coast, and fluvial mud and sands from the Shoalhaven River. Molluscan assemblages indicate that marine influence was initially widespread throughout the eastern and southern parts of the embayment and that most of the plains infilled under estuarine conditions. Prominent levees across the plains surface are interpreted to be part of a birdsfoot delta distributary complex, and individual floodbasins accreted progressively as they were encapsulated by distributary extension. These former tidal environments mean that there are extensive potential acid sulphate soil conditions beneath the plains. The upper occurrence of Notospisula in drillholes records the cessation of tidal influence, and diatoms from the top of one drillhole record the transition from brackish conditions to freshwater alluvial sedimentation. Radiocarbon dating provides a chronology of mid-Holocene ecological changes on the plains.

DOI： 10.1191/095968301678302841

Web of Science

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Language：Japanese  

DOI： 10.4116/jaqua.40.345

CiNii Books

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Language：Japanese  

CiNii Books

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Language：Japanese   Publisher：名古屋大学  

The purpose of this study is to clarify a sedimentary process and paleoenvironments in the Kumozu river lowland during the late Holocene. Clayey and silty sediments above deltaic sand are consider to have been deposited in a stable backswamp. These muddy sediments are covered with fluvial fine sand. AMS datings make it clear that an emergence of the lowalnd around the section happened before ca. 3200-2600yrBP and fluvial sand widely deposited since 2200yrBP.

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Language：Japanese  

CiNii Books

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Language：English   Publisher：日本熱帯生態学会  

DOI： 10.3759/tropics.8.317

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Language：Japanese   Publisher：名古屋大学  

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Language：Japanese   Publisher：名古屋大学  

This paper reports AMS radiocarbon dating of uppermost sediments in the Toyogawa plain. Deposits were obtained in order to clarify a sedimentary process and a geomorphic change in this plain during the late Holocene. Five ages collectted from the sediments were measured. Refering to archaeological excavations, the author pointed out that expansion of the plain was probably intermittent and/or a erosion and filling happened since ca. 2,700 yrBP.

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Language：English   Publisher：国立歴史民俗博物館  

中部日本の矢作川下流低地において，縄文海進のおよんだ地域を対象として，ボーリング資料の整理，加速器質量分析計による堆積物の¹⁴Ｃ年代値の測定，珪藻分析を行い，完新世後半の低地の地形環境の変化を明らかにした。表層地質の整理から，沖積層上部砂層の上位に腐植物混じりの後背湿地堆積物が堆積し，洪水氾濫堆積物と考えられる砂層によって覆われていることが明らかとなった。後背湿地堆積物を覆う砂層は，支流沿いでは自然堤防を構成している。堆積物の珪藻分析結果は，後背湿地堆積物が安定した止水環境で堆積し，その上位は流水の影響が強まったことを示唆しており，堆積物からみた堆積環境の変遷を支持している。静穏な環境から河成作用が卓越する環境への変化は，約2,000年前におこった。本研究で推定された上記の環境変化が，対象地域の上流部においてもみられたことが従来の研究で指摘されている。それらによれば，約2,000年前頃から洪水氾濫の影響が強くなり，古墳時代には顕著な自然堤防が形成されるようになった。この一連の堆積環境の変化には，気候の湿潤化による洪水氾濫の激化と，人為的な森林破壊による土砂供給量の増大が関与している可能性がある。The author researched the geomorphic development and paleoenviornmental changes in the Yahagi River Lowland, Central Japan. Sedimentological analysis of the boring-core data and diatom analysis were done for the southern area of the lowland which was inundated by the Holocene transgression. The stratigraphy of uppermost deposits suggests that the environment of this region has changed from broad marsh with several ponds to unstable land which damaged by frequent floods. The results of diatom analysis support this sedimentary condition. The fluvial effect in the Yahagi River Lowland had become significant since ca. 2,000 yr. B.P., and natural levees had developed after ca. 1,200-1,400 yr. B.P. It has been reported by the previous study that the similar environmental change was seen in the northern half of this lowland. The causes of such environmental and geomorphological changes are considered to be due to the climatic change and deforestation by human activity in the upper reaches.

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Language：English   Publisher：JAPAN SOCIETY OF TROPICAL ECOLOGY  

Holocene landforms and sediments of the coastal lowlands around Satun and Songkhla Lake regions in southern Thailand are studied in relation to mangrove habitat. <BR> Landforms of the Satun lowland are net a simple geomorphic surface but the surfaces of Pleistocene and late Holocene. Present mangrove vegetation develops mainly en the Holecene surface in the southern part of Satun lowland. The area is almost the same as that covered with mangrove in the period of Holocene maximum transgression. Based on the fuceis and ages of the sediments in the Satun lowland, sedimentation rate of the lowland since 1000 yr BP is relatively rapid and the mangrove forest expanded rapidly in the period. <BR> On the other hand, most mangrove forest has already disappeared in the coastal lowland along Lake Songkhla. The thickness of the Holocene sediments is less than 5 meters in most. t places, and consists of peat layer and overlying muddy sediments. Based on the radiocarbon ages of the peat layers collected from the southern part of the coastal lowland, mangrove forest started to develop around 6700 yr BP and expanded rapidly in the region. This is because the surface of the Pleistocene sediments is. very flat and shallow. Seawater invaded and expanded in the region very quickly and formed a wide tidal plain along the coast of lagoon. This condition causes rapid expansion of mangrove forest along the Songkhla Lake. <BR> Based en these facts, it is clarified that the development of mangrove forests in the study areas is related to the evolution of the Holocene coastal landforms. and deposition of sediments in mid to late Holecence. Furthermore, landform evolution and sedimentation arc related to the landforms of the pre-Holocene surface.

DOI： 10.3759/tropics.8.317

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Language：English   Publisher：JAPAN SOCIETY OF TROPICAL ECOLOGY  

Holocene landforms and sediments of the coastal lowlands around Satun and Songkhla Lake regions in southern Thailand are studied in relation to mangrove habitat. <BR> Landforms of the Satun lowland are net a simple geomorphic surface but the surfaces of Pleistocene and late Holocene. Present mangrove vegetation develops mainly en the Holecene surface in the southern part of Satun lowland. The area is almost the same as that covered with mangrove in the period of Holocene maximum transgression. Based on the fuceis and ages of the sediments in the Satun lowland, sedimentation rate of the lowland since 1000 yr BP is relatively rapid and the mangrove forest expanded rapidly in the period. <BR> On the other hand, most mangrove forest has already disappeared in the coastal lowland along Lake Songkhla. The thickness of the Holocene sediments is less than 5 meters in most. t places, and consists of peat layer and overlying muddy sediments. Based on the radiocarbon ages of the peat layers collected from the southern part of the coastal lowland, mangrove forest started to develop around 6700 yr BP and expanded rapidly in the region. This is because the surface of the Pleistocene sediments is. very flat and shallow. Seawater invaded and expanded in the region very quickly and formed a wide tidal plain along the coast of lagoon. This condition causes rapid expansion of mangrove forest along the Songkhla Lake. <BR> Based en these facts, it is clarified that the development of mangrove forests in the study areas is related to the evolution of the Holocene coastal landforms. and deposition of sediments in mid to late Holecence. Furthermore, landform evolution and sedimentation arc related to the landforms of the pre-Holocene surface.

DOI： 10.3759/tropics.8.317

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Language：Japanese   Publisher：学術雑誌目次速報データベース由来  

The Yahagi River lowlands are located along the lower reaches of the Yahagi River in central Japan. The author researched and discusses the geomorphic development and paleoenvironmental changes in the lowlands during the late Holocene, using sediment analysis of boring-core data, AMS &lt;sup&gt;14&lt;/sup&gt;C dating, diatom analysis, and archaeological data. Some changes in the sedimentary environment were clarified by the facies and diatom assemblages of the sediments.&lt;br&gt; In the northern part of the study area, the uppermost sediments indicate that the delta-platform emerged at ca. 3, 000 yr BP, and peat and humic soil were formed under stable conditions. After ca. 2, 000 yr BP, the sedimentary environment became unstable, and the peaty or humic sediments were covered with sandy ones which were deposited by flooding. The fluvial influence was dominant in the periods around 2, 000 yr BP and ca. 1, 400-1, 200 yr BP.&lt;br&gt; In the northwestern part of the present lowlands, the subaerial delta expanded widely during ca. 3, 000-2, 500 yr BP. The molluscan species of archaeological shell mounds in the southwestern part indicate that an inlet remained near the region until ca. 1, 000 yr BP. This suggests that the progra-dation of the delta was slow before that time.&lt;br&gt; In the eastern part, the sedimentary environment of the brackish lake or marsh changed to a &lt;br&gt;freshwater environment around ca. 1, 500 yr BP. Around this time, the delta probably emerged and the formation of peaty sediments began.&lt;br&gt; The remarkable expansion of the subaerial delta during ca. 3, 000-2, 500 yr BP was possibly influ-enced by minor sea-level changes in the late Holocene, the so-called Yayoi minor regression. It is also possible that climatic change and/or human activities influenced the deposition of sandy sediments over the peaty or humic ones.

DOI： 10.4157/grj1984a.71.6_411

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Language：Japanese   Publisher：名古屋大学  

Over the past few decades a considerable number of studies have been made on the sediments and geomorphic developments of the coastal plains in Japan. However, little attention has been given to the uppermost sediments. The author consider that the raiocarbon datings of that sediments help to understand the patterns of the expantion of deltas and to reconstruct the terrestrial environmental changes during the Holocene. This paper introduces the example of the Yahagi River Lowland in the central Japan. In this lowland, the following results were obtained by using sedimentological analysis of boring-core data, AMS ^&lt;14&gt;C dating, diatom analysis, and archaeological data. The subaerial-delta expanded widely during ca 3,000-2,500yr BP in the northern part of this area. This remarkable expansion of delta was possiblly influenced by the minor sea-level changes in the late Holocene : so-called &#039;Yayoi Minor Regression&#039;. And fluvial influence was dominant in the periods around 2,000yrBP. These changes of sedimentary environments were possibility influenced by the climatic change and/or some human activities.

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Language：English   Publisher：名古屋大学  

タンデトロン加速器質量分析計業績報告 Summaries of Researches Using AMS 1997 (平成9)年度

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Language：Japanese  

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Language：Japanese   Publisher：名古屋大学  

タンデトロン加速器質量分析計業績報告 Summaries of Research Using AMS 1995(平成7)年度

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Language：Japanese   Publisher：日本活断層学会  

Two humic silty layers were found at the level of +8.0m and +8.5m above sea level in the sediments of the Nakanawa archaeological site near Kuwana, central Japan. Radiocarbon age of the lower layer is dated as 2040±100yrs BP, and the layer is considered to have been deposited in a marine or brackish environment near the coast judging from the diatom assemblage.&lt;BR&gt;These facts show that the site has uplifted at a rate of ca 4m/1000 yrs since 2000 yrs BP, and this implies that the Kuwana fault is A-class active fault.&lt;BR&gt;Many tracks of sandblow are also found in the sediments of the site, and the uplifting movements are considered to have been associated with the historical earthquakes such as the Kaho earthquake in1096 and Tensho earthquake in 1586.

DOI： 10.11462/afr1985.1996.15_17

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Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Oral presentation (general)  

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