USNM9269, Block 4, Khao Chang Hill, Rat Buri (Permian of Thailand)

Where: Ratchaburi, Thailand (13.4° N, 99.8° E: paleocoordinates 30.9° S, 100.5° E)

• coordinate based on nearby landmark

• small collection-level geographic resolution

When: Rat Buri Formation, Roadian (272.3 - 268.8 Ma)

• Blocks sampled were either "in place" in the limestone mass; others were from float. But because the jungle terrain makes measurement of stratigraphic sections difficult, the stratigraphy is unknown. The age of the Rat Buri fauna is problematic. "Rat Buri" limestones likely range in age from Kungurian through Capitanian to perhaps Wuchiapingian. Wordian fusulinids appear most common in other collections, but are not found in association with the brachiopod localities. The brachopod fauna is most similar to the Wordian Amb Formation of the Salt Range, in Pakistan, tentatively indicating a Wordian age.

• group of beds-level stratigraphic resolution

Environment/lithology: offshore shelf; black, argillaceous, carbonaceous limestone

• Calm water below wave base
• Black limestone that left a large residue of carbonaceous clay after acid leaching

Size class: macrofossils

Preservation: replaced with silica

Collection methods: bulk, surface (float), surface (in situ), chemical,

Primary reference: R. E. Grant. 1976. Permian brachiopods from southern Thailand. Paleontological Society Memoir 9:1-269 [D. Bottjer/M. Clapham/M. Clapham]more details

Purpose of describing collection: paleoecologic analysis

PaleoDB collection 40867: authorized by David Bottjer, entered by Matthew Clapham on 02.07.2004

Creative Commons license: CC BY (attribution)

Taxonomic list

• Concentrated on brachiopods; other groups are briefly mentioned in text for the locality in general but not reported in detail for individual blocks.
Strophomenata
 Productida - Productellidae
"Marginifera otaria" = Marginifera (Otariella) otaria
"Marginifera otaria" = Marginifera (Otariella) otaria Grant 1976
Rhynchonellata
 Athyridida - Diplospirellidae
 Athyridida - Athyrididae
"Composita subsolana" = Posicomta subsolana
"Composita subsolana" = Posicomta subsolana Grant 1976
 Spiriferinida - Spiriferellinidae
"Spiriferellina adunctata" = Spiriferellina aduncata
"Spiriferellina adunctata" = Spiriferellina aduncata Waterhouse and Piyasin 1970