TY - JOUR
T1 - Significance of autochthonous fossil barnacles from the Miocene Natori Group at the Moniwa-Goishi area, northeast Japan
AU - Nomura, Shin Ichi
AU - Maeda, Haruyoshi
N1 - Funding Information:
Compliant surface foil air bearings are self-acting, hydrodynamic bearings lubricated by ambient air. Foil bearings are made up of one or more compliant layers, or foils, of corrugated sheet metal and one or more layers of flat sheet metal, Fig. 1. The foil bearing discussed in this work is described in detail by Heshmat (I). As shown, the inner layer, or top foil is smooth and supports the fluid film. The top foil is supported by the compliant bump foil. These compliant foils deform under pressure from the hydro-
PY - 2008/4/30
Y1 - 2008/4/30
N2 - In situ fossil barnacle populations (Cirripedia, Balanomorpha) are described from the Miocene Natori Group of the Moniwa-Goishi area, northeast Japan. The Natori Group exhibits a transgressive sequence from subaerial lavas and volcaniclastics (Takadate Formation) to shoreface-shelf deposits (Moniwa and Hatatate formations) in ascending order. In the Takadate Formation, volcaniclastics locally intercalate bay deposits in which the fossil barnacle Balanus bisuleatus occurs on gravel surfaces in situ. The Takadate Formation is unconformably overlain by the basal conglomerate of the Moniwa Formation, which is interpreted as a ravinement deposit formed in an open coast. An extinct barnacle species, Concavus sendaicus, is found as gregarious clusters and solitary individuals on boulder surfaces in the basal conglomerate in situ. These features suggest that B. bisuleatus inhabited in bay environments at the early transgressive stage. On the other hand, C. sendaicus was distributed over open-coast environments during subsequent marine flooding. The in situ C. sendaicus provides strong evidence for the reconstruction of the extinct species habitat.
AB - In situ fossil barnacle populations (Cirripedia, Balanomorpha) are described from the Miocene Natori Group of the Moniwa-Goishi area, northeast Japan. The Natori Group exhibits a transgressive sequence from subaerial lavas and volcaniclastics (Takadate Formation) to shoreface-shelf deposits (Moniwa and Hatatate formations) in ascending order. In the Takadate Formation, volcaniclastics locally intercalate bay deposits in which the fossil barnacle Balanus bisuleatus occurs on gravel surfaces in situ. The Takadate Formation is unconformably overlain by the basal conglomerate of the Moniwa Formation, which is interpreted as a ravinement deposit formed in an open coast. An extinct barnacle species, Concavus sendaicus, is found as gregarious clusters and solitary individuals on boulder surfaces in the basal conglomerate in situ. These features suggest that B. bisuleatus inhabited in bay environments at the early transgressive stage. On the other hand, C. sendaicus was distributed over open-coast environments during subsequent marine flooding. The in situ C. sendaicus provides strong evidence for the reconstruction of the extinct species habitat.
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U2 - 10.2517/1342-8144(2008)12[63:SOAFBF]2.0.CO;2
DO - 10.2517/1342-8144(2008)12[63:SOAFBF]2.0.CO;2
M3 - Article
AN - SCOPUS:44649090215
VL - 12
SP - 63
EP - 79
JO - Paleontological Research
JF - Paleontological Research
SN - 1342-8144
IS - 1
ER -