Holocene Environmental Changes in the Southern Part of Miyagino Coastal Plain, Miyagi Prefecture, Japan

概要

論文の詳細を見る
Three sedimentary cores recovered from the Iwanuma area in the southern part of Miyagino coastal plain, Miyagi Prefecture, are examined by means of diatom and pollen analyses to clarify the sedimentary environment and past vegetation. The Holocene deposits in this area are subdivided into the lower part composed mainly of silt, the middle part composed of sand, and the upper part composed of irregularly alternating beds of sand, silt, and peaty silt. From the diatom analysis, the sedimentary environment in this area is as follows. At about 10, 000yrs BP a tidal flat environment was created in response to the sea-level rise called the postglacial transgression, and the lower part of the silt bed was deposited. After that, an inner bay environment pervaded owing to the continuous sea-level rise, and consequently the middle sand bed was deposited. The terrestrial environment became established after the emergence of this area about 3, 500 14C yrs BP. The pollen analysis indicates that the temperate deciduous broad-leaved forest dominated by Quercus, admixed with Fagus and Carpinus, has covered the surrounding hilly lands since about 10, 000 14C yrs BP. In the fairly stable vegetation during the Holocene mentioned above, Ulmus-Zelkova and Cryptomeria have existed in small amounts since the early Holocene, and increased after about 8, 000 14C yrs BP because of local topographic changes.
日本第四紀学会の論文