@article{oai:rekihaku.repo.nii.ac.jp:00000919,
 author = {吉川, 昌伸 and Yoshikawa, Masanobu},
 journal = {国立歴史民俗博物館研究報告, Bulletin of the National Museum of Japanese History},
 month = {Mar},
 note = {application/pdf, 約12,000万年前以降の関東平野の層序と環境変遷史を検討し，変化期について考察した。完新世の有楽町層は，下部層は主に縄文海進期の海成層から，上部層は河成ないし三角州成堆積物から構成されるが，台地の開析谷内では上部層形成期にはふつう木本泥炭層が形成され，弥生時代以降に主に草本泥炭層に変化した。沖積低地では約4,000年前と約2,000年前には海水準の低下により浅谷が形成された。
約12,000年前，冷温帯ないし亜寒帯性の針葉樹と落葉広葉樹からなる森林が，コナラ亜属を主とする落葉広葉樹林に変化した。クリは，約10,500年前以降に自然植生として普通に分布し，縄文中期から晩期（約5,000～2,150年前）には各地で優勢になった。クリ林の拡大が海退と関係することから，環境変化に起因して起こった人為的な変化と推定した。照葉樹林は，房総半島南端では約7,000年前に既に自生し，奥東京湾岸で約7,500年前に，東京湾岸地域の台地で約3,000年前に拡大したが，内陸部では落葉広葉樹林が卓越した。照葉樹林の拡大が関東平野南部から北部，沿岸域から内陸部へと認められたことから，海進による内陸部の湿潤化が関係すると考えた。スギ林は南関東では約3,000年前までに拡大し，その後北部に広がった。照葉樹林やスギ林は，弥生時代以降には内陸部の武蔵野台地や大宮台地，北関東でも拡大が認められたが，これら森林の拡大には生態系への人間の干渉も関係した。また，丘陵を主とするモミ林の拡大は古墳時代頃の湿潤化に起因して，マツ林は特殊な地域を除いては14～15世紀以降に漸増し18世紀初頭以降に卓越した。こうした関東平野の沖積低地の層序や植物化石群に基づき，約12,000年前以降にPE,HE1,HE2,HE3,HE4,HE5各期の６つの変化期を設定した。各変化期は，陸と沖積低地の双方で起こった変化であることを明らかにした。, Stratigraphy and environmental changes during the last 12,000 years in the Kanto Plain are as follows.
The alluvial deposit of the Kanto Plain is divided into two formations, the Nanagochi Formation of the latest Pleistocene, and the Yurakucho Formation of the Holocene. The Yurakucho Formation unconformably covers the Nanagochi Formation with the basal gravel bed (HBG) formed about 10,500 yrs. B.P. The Yurakucho Formation is divided into two formations, the lower one composed mainly of marine deposits during the Jomon Transgression, and the upper one mainly consisting of fluvial and delta deposits. During the deposition of the Upper Yurakucho Formation, dissected valleys in the upland were filled mainly with wood peat, and with herbaceous peat since the Yayoi Period.
At about 12,000 yrs. B.P., cool-temperate to boreal coniferous and deciduous broadleaved forests changed into deciduous broad-leaved forests dominated by Quercus subgen. Lepidobalanus in the Kanto Plain. Castanea flourished usually as natural vegetation since about 10,000 yrs. B.P. During the Middle to Later Jomon Period (ca. 5,000-2,150 yrs. B.P.), Castanea forests expanded in many places on the upland. This expansion of Castanea forests was artificially induced by an environmental change. Evergreen broad-leaved forests already flourished at the southern end of the Boso Peninsula in 7,000 yrs. B.P., and expanded since about 7,500 yrs. B.P. along the coast of Oku-Tokyo Bay and at 3,000 yrs. B.P. on the coast of Tokyo Bay. However, deciduous broad-leaved forest flourished on the inner upland. The increase in the inland humidity induced by the Jomon Transgression must have caused expansion of evergreen broad-leaved forests from the southern part to north of the Kanto Plain and from coast to inland. Cryptomeria forests expanded by about 3,000 yrs. B.P. in the south Kanto and spread to the northern region. Evergreen broad-leaved forests and Cryptomeria forests expanded also on the Musashino Upland, Oomiya Upland, and North Kanto since the Yayoi Period. Expansion of these forests was induced not only by nature but also by human impact on ecosystem. Six epoch-making events of PE, HE1, HE2, HE3, HE4, HE5 are identified based on stratigraphy and plant fossil assemblages of the alluvial lowland during the last 12,000 years in the Kanto Plain. Each event corresponds to a change both on the land and in the alluvial lowland.},
 pages = {267--287},
 title = {関東平野における過去12,000年間の環境変遷（日本列島と周辺域における環境変遷）},
 volume = {81},
 year = {1999},
 yomi = {ヨシカワ, マサノブ}
}