Ayugawa Group

Ayugawa Group Ikebe, 1934

Coherent formation
First Seto Inland Sea
Sedimentary basin in island arc
Miocene

Sedimentary facies: Marine
Lithofacies:

Distribution (East - West): ca. 10 km
Distribution (South - North): ca. 8 km
Thickness: 350 - 750 m
Upper limit: Unconformity (Kobiwako Group)
Lower limit: Unconformity (Yasugawa Group)

Ayugawa Group
[ Upper ]
~~~~~~~~~~~~~~
Marutadani Formation
--------------
Kurokawa Formation
--------------
Tsuchiyama Formation
~~~~~~~~~~~~~~
[ Lower ]

First Setouchi Supergroup (Tsuchiyama, Shiga pref.)
[ Upper ]
~~~~~~~~~~~~~~
Ayugawa Group
~~~~~~~~~~~~~~
[ Lower ]

[ Upper ]
~~~~~~~~~~~~~~
Second Setouchi Supergroup
?--?--?--?--?-
First Setouchi Supergroup
~~~~~~~~~~~~~~
[ Lower ]

------ Conformity, ~~~~~~ Unconformity, ~~~--- Local unconformity, '''/,, Interfingered, :::::: Fault, /--/-- Thrust, +__+__ Ground surface, ?--?-- Unknown

Distribution: Tsuchiyama town, Koka city, Shiga pref.
Fossils: Mammals (Delphindae? gen. et sp. indet., Pinipedia gen. et sp. indet.), Fishes (pterotrissus spp.), Sharks (Carcharhinus priscus, Negaprion sp.), Crustaceans (Balanus spp., Callianassa sp., Dorippe sp., Philyra sp.), Brachiopods (Discinisca stella, Lingula sp., Terebratalia sp.), Echinoids (Echinocyamus crispus, Kewia minoensis), Bryozoans (Membranipora sp., Microporella sp., Moroporella sp.), Foraminifera (Globigerinoides spp.)
Fossils (Shellfishes): Acila submirabilis, Anomalodiscus sp., Boreotrophon osawanoensis, Cavolinia sp., Crassostrea gigas, Crepidula jimboana, Cultellus izumoensis, Cyclocardia siogamensis, Cyclyna japonica, Dentalium sp., Dosinia kawagensis, Dosinia nomurai, Euspira meisensis, Fabulina sp., Felaniella usta, Glycymeris ikebei, Hiatula minoensis, Lucinoma acutilineatum, Mactra sp., Moerella sp., Mya japonica, Nipponomarcia nakamurai, Ostrea sp., Pandora otukai, Panomya simotomensis, Patinopecten egregius, Periploma mitsuganoensis, Phos minoensis, Ringicula sp., Saccella miensis, Siliqua minoensis, Siratoria siratoriensis, Solen sp., Thracia watanabei, Trapezium modiolaeforme, Turretella sagai, Vaginella depressa, Vicarya yokoyamai, Vicaryella bacula
Fossils (Plants): Abies sp., Comptonia naumanni, Juglans sp., Metasequoia occidentalis, Pinus sp., Quercus sp., Spondias axillaris, Zelkova sp.

Miyamura et al. (1981) Geology of the Kameyama District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 128p. (in Japanese with English abstract 9p.)