KT boundary Brazos 1 - A1.75 (Cretaceous of the United States)

Also known as Brazos River Section

Where: Texas (31.1° N, 96.8° W: paleocoordinates 34.5° N, 66.6° W)

• coordinate estimated from map

When: Corsicana Formation, Late/Upper Cretaceous (100.5 - 66.0 Ma)

Environment/lithology: deep subtidal shelf; claystone

• middle to outer shelf environment
• Brazos-1 comprises approx. 1m of Cretaceous clay with dark clay clasts (up to 10 cm in diameter) at the base (Unit A) with evidence of physical disruption

•also see Figure 3 for the detailed section; Units B-E probably form a tempestite or tsunami

Size classes: macrofossils, mesofossils

Collection methods: bulk

Primary reference: T. Hansen, R. B. Farrand, H. A. Montgomery, H. G. Billman, and G. Blechschmidt. 1987. Sedimentology and extinction patterns across the Cretaceous-Tertiary boundary interval in East Texas. Cretaceous Research 8:229-252 [B. Seuss/B. Seuss]more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 225663: authorized by Barbara Seuss, entered by Barbara Seuss on 24.05.2022

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names
unclassified
  -
Heterohilicidae indet., Micula mura, Nuculopsis sp.
Cephalopoda
 Ammonitida - Baculitidae
Baculites sp.
Baculites sp. Lamarck 1799 ammonite
Bivalvia
 Nuculanida - Nuculanidae
Nuculana coloradoensis, Nuculana travisana, Nuculana "sp. A"
Nuculana coloradoensis pointed nut clam
Nuculana travisana pointed nut clam
Nuculana "sp. A" Link 1807 pointed nut clam
 Ostreida - Ostreidae
Ostrea "sp. A", Ostrea sp.
Ostrea "sp. A" Linnaeus 1758 oyster
Ostrea sp. Linnaeus 1758 oyster
 Ostreida - Flemingostreidae
"Ostrea tecticosta" = Cubitostrea tecticosta
"Ostrea tecticosta" = Cubitostrea tecticosta Gabb 1860 oyster
 Pectinida - Limidae
Lima sp.
Lima sp. Bruguière 1797 file clam
 Pectinida - Entoliidae
Syncyclonema simplicus
 Arcida - Arcidae
Striarca webbervillensis
Scaphopoda
 Dentaliida - Dentaliidae
Dentalium "sp. B"
Dentalium "sp. B" Linnaeus 1758 tusk shell
Gastropoda
 Sorbeoconcha - Naticidae
Naticidae indet.
Naticidae indet. Guilding 1834 moon snail
Foraminifera
  - Guembelitriidae
Guembelitria cretacea
Guembelitria cretacea Cushman 1933
 Globigerinaceae - Heterohelicidae
Pseudoguembelina sp., Heterohelix striata, Heterohelix navarroensis
Heterohelix striata Ehrenberg 1840
Heterohelix navarroensis Loeblich 1951
Coccolithophyceae
 Braarudosphaerales - Polycyclolithaceae
Micula prinsii
Micula prinsii Perch-Nielsen 1979 coccolithophore
 Podorhabdales - Axopodorhabdaceae
Nephrolithus frequens