KT boundary Brazos 1 - A4.50 (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 225660: 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
Coccolithophyceae
 Podorhabdales - Axopodorhabdaceae
Nephrolithus frequens
 Braarudosphaerales - Polycyclolithaceae
Micula prinsii
Micula prinsii Perch-Nielsen 1979 coccolithophore
unclassified
  -
Heterohilicidae indet., Micula mura, Margaritella sp.
Foraminifera
  - Guembelitriidae
Guembelitria cretacea
Guembelitria cretacea Cushman 1933
 Globigerinaceae - Heterohelicidae
Heterohelix striata, Heterohelix navarroensis, Pseudoguembelina sp.
Heterohelix striata Ehrenberg 1840
Heterohelix navarroensis Loeblich 1951
Bivalvia
 Pectinida - Entoliidae
Syncyclonema simplicus
 Ostreida - Flemingostreidae
"Ostrea tecticosta" = Cubitostrea tecticosta
"Ostrea tecticosta" = Cubitostrea tecticosta Gabb 1860 oyster
 Ostreida - Ostreidae
Ostrea sp.
Ostrea sp. Linnaeus 1758 oyster
 Arcida - Arcidae
Striarca webbervillensis
 Carditida - Carditidae
Vetericardiella webbervillensis
 Cardiida - Mactridae
Cymbophora cancellosa
 Pholadida - Corbulidae
Corbula sp.
Corbula sp. Bruguière 1789 clam
 Nuculida - Nuculidae
Nucula "sp. A"
Nucula "sp. A" Lamarck 1799 nut clam
 Nuculanida - Nuculanidae
Nuculana coloradoensis, Nuculana "sp. A", Nuculana sp., Nuculana "sp. E", Nuculana protexta
Nuculana coloradoensis pointed nut clam
Nuculana "sp. A" Link 1807 pointed nut clam
Nuculana sp. Link 1807 pointed nut clam
adult, juvenile
Nuculana "sp. E" Link 1807 pointed nut clam
Nuculana protexta pointed nut clam
Scaphopoda
 Gadilida - Gadilidae
Cadulus obnutus
Cadulus obnutus tusk shell
 Dentaliida - Dentaliidae
Dentalium "sp. B", Dentalium leve
Dentalium "sp. B" Linnaeus 1758 tusk shell
Dentalium leve Stephenson 1923 tusk shell
Cephalopoda
 Ammonitida - Scaphitidae
Scaphites sp.
Scaphites sp. Parkinson 1811 ammonite
 Ammonitida - Baculitidae
Baculites sp.
Baculites sp. Lamarck 1799 ammonite
Gastropoda
  -
Gastropoda indet.
Gastropoda indet. Cuvier 1795 snail
 Sorbeoconcha - Naticidae
Naticidae indet.
Naticidae indet. Guilding 1834 moon snail