名古屋港周辺の完新統とその基底地形

抄録

By means of the analysis of many boring cores collected by the Authority of Nagoya Port, the authors studied the geology and stratigraphy of recent alluvial deposits and made clear the buried topography beneath the southern part of the Nobi Plain. As a result, following conclusions were induced.
The basal topography beneath the recent alluvial deposits is classified into four buried geomorphological surfaces in descending order, 1) the buried wave-cut platform (shallower than -15m), 2) the buried surface of the Atsuta terrace, 3) the buried surface of the Toriimatsu terrace and 4) the buried valley bed. Recent alluvial materials upon the basal gravel beds are divided into four beds in acending order, 1) the Lower Sands, 2) the Middle Muds, 3) the Upper Sands and 4) the Top Muds, The Lower Sands (a so-called Nobi Formation) were deposited in the late glacial time as the foreset bed of delta, their ages are about 18, 000 to 13, 000y.B.P, by ¹⁴C dating. The Middle Muds (20 to 10m thick) were deposited as the bottomset bed of delta in the extended Ise Bay of the Holocene transgression time and their ¹⁴C dating ages are about from 9000 to 5000y.B.P. containing the Akahoya volcanic ash layer (Ah). The Upper sands were deposited as progressing foreset bed of delta after the age of the maximum sea level of Holocene transgression. The age of this deposition around the Nagoya harbour is 2500 or 2000y.B.P. The Top Muds along the coastal district are the artificial earth materials on reclaimed lands.