USGS 17542 - Yontan Limestone, Ryukyu Group, Okinawa (Pleistocene of Japan)

Also known as WF 233

Where: Okinawa, Japan (26.4° N, 127.8° E: paleocoordinates 26.5° N, 127.5° E)

• coordinate estimated from map

• outcrop-level geographic resolution

When: Yontan Limestone Member, Early/Lower Pleistocene (2.6 - 0.8 Ma)

• The Yontan Limestone is the upper part of the Ryukyu Limestone. Some parts of the Yontan Limestone have a tecture similar to parts of the Naha Limestone, but in general the Yontan is coarser. Locally it consists of unsorted detrital fragments up to a foot in dimension. None of the fragments can be identified as Naha Limestone. The rock is highly porours to dense. The greatest observed thickness of the Yontan Limestone is about 200 ft, elsewhere the greatest thickness is around 40 ft. The Yontan Limestone rests on Paleozoic rocks, on beds of the Shimajiri Fm, or on the Naha Limestone. Its contact with the later is a wavy erosional discontinuity.

• bed-level stratigraphic resolution

Environment/lithology: poorly lithified, coarse-grained, conglomeratic limestone

• Shallow water carbonate environment? No specific paleoenvironmental data provided.
• Limestone, though coarser than that of the Naha. Locally it consists of unsorted detrital fragments up to a foot in dimension

Size class: macrofossils

Preservation: original aragonite

Collection methods: quarrying,

• Collections held in USNM and UGSG repositories.

Primary reference: F. S. MacNeil. 1960. Tertiary and Quaternary Gastropoda of Okinawa: A comparison of the late Miocene, Pliocene, and Pleistocene Gastropoda of Okinawa with related faunas of East Asia together with a resume of the geological setting of the fossiliferous deposits. United States Geological Survey Professional Paper 339:1-148 [A. Miller/C. Ferguson/P. Wagner]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 42357: authorized by Austin Hendy, entered by Austin Hendy on 28.07.2004

Creative Commons license: CC BY (attribution)

Taxonomic list

• Exhaustive for gastropoda. No bivalves.
 Neogastropoda - Muricidae
Magilus antiquus Montfort 1810 murex snail
 Cypraeoidea - Cypraeidae
"Erosaria (Erosaria) erosa" = Naria erosa
"Erosaria (Erosaria) erosa" = Naria erosa Linnaeus 1758 cowry