Hiraiso Fm. in the Hiraiso Coast, Facies Ha (Triassic of Japan)

Where: Miyagi, Japan (38.8° N, 141.5° E: paleocoordinates 38.5° N, 118.8° E)

• coordinate estimated from map

• outcrop-level geographic resolution

When: Hiraiso Formation, Spathian (251.3 - 247.2 Ma)

• Bando (1970) originally assigned the Hiraiso Fm. to the Griesbachian, later it was assigned to the Smithian by Nakazawa et al. (1994). Reidentification of Bando's ammonite as Neocolumbites and discovery of Tirolites in the lower part of the formation suggests a Spathian age for the Hiraiso Formation (Shigeta & Nakajima, 2017). Listed fossils belong to the Facies Ha, one of nine identified facies in the Hiraiso Fm.

• group of beds-level stratigraphic resolution

Environment/lithology: offshore; lithified sandstone

• Upper inner shelf.
• Thick hummocky-laminated sandstones with basal shelly deposits (amalgamated HCS).

Size class: macrofossils

Preservation: cast, mold/impression

Primary reference: Y. Kashiyama and T. Oji. 2004. Low-diversity shallow marine benthic fauna from the Smithian of northeast Japan: paleocologic and paleobiogeographic imlications. Paleontological Research 8(3):199-218 [W. Kiessling/S. Nurnberg/S. Nurnberg]more details

Purpose of describing collection: paleoecologic analysis

PaleoDB collection 50116: authorized by Wolfgang Kiessling, entered by Sabine Nürnberg on 09.05.2005

Creative Commons license: CC BY (attribution)

Taxonomic list

Bivalvia
 Trigoniida - Myophoriidae
Neoschizodus cf. laevigatus Ziethen 1830 clam
 Cardiida - Anthracosiidae
Unionites aff. canalensis Catullo 1847 clam
questionable; U. aff. canalensis var. fassaenis
 Pectinida - Aviculopectinidae
Eumorphotis iwanowi Bittner 1899 scallop
 Pectinida - Entoliidae
 Ostreida - Bakevelliidae
Crinoidea
 Holocrinida - Holocrinidae
Holocrinus sp. Wachsmuth and Springer 1886 Sea lily