Walvis Ridge, dredge CH 18 DR 04 (Cretaceous to of South Atlantic)

Where: South Atlantic (19.6° S, 9.0° E)

• coordinate stated in text

• outcrop-level geographic resolution

When: Albian to Albian (113.2 - 93.9 Ma)

• One specimen of Neithea could be Neithea cf. shawi Pervinquiere (= N. coquandi Peron). The distribution of N. shawi is Albian-Cenomanian in the Angola Basin but mostly Cenomanian in northern Africa. This specimen is, however, poorly preserved and could belong to the species N. regularis Schlotheim. In Europe the distribution of N. regularis Schlotheim ranges from Turonian to Senonian. Thus the macrofossils indicate an Albian Senonian age. The nannofossils consist mainly of Lithastrinus floralis Stradner. Cricolithus multiradiatus Kamptner, C. pemmatoideus Deflandre, Loxolithus armilla (Black) and Parhabdolithus embergeri (Noel). These are typical Albian-Cenomanian species.

• group of beds-level stratigraphic resolution

Environment/lithology: lithified, white chalk

• Hypotheses for a depositional environment of the sediments, which might explain the observed association include ( 1) the coccoliths accumulated in deep water and the macrofossils are thanatocoenoses transported from shallow depths by turbidity currents or some other process; (2) both the coccoliths and macrofossils were deposited in shallow water. We favour the second hypothesis, tentatively rejecting a mixed origin for the sediments because of the distance from the African coast and the absence of local seamounts. A shallow water environment would comply with the ecological needs of the macrofossils. Neithea, for example, is commonly found in shallow water Alba-Cenomanian deposits in the Angola Basin. Furthermore, coccoliths are epipelagic organisms and cannot be used as precise depth indicators. Although they are typical of open sea sedimentation, their occurrence does not necessarily imply deep water.

Size classes: macrofossils, microfossils

Collected by RV Jean Charcot in 1971

Collection methods: surface (float)

Primary reference: L. Pastouret and J. Goslin. 1974. Middle Cretaceous sediments from the eastern part of Walvis Ridge. Nature 248:495-496 [M. Clapham/M. Clapham]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 209782: authorized by Matthew Clapham, entered by Matthew Clapham on 15.05.2020

Creative Commons license: CC0 (CC0)

Taxonomic list

Bivalvia
 Heteroconchia -
Heterodonta indet. Neumayr 1884 clam
 Arcida -
"Arcacea indet." = Arcoidea
"Arcacea indet." = Arcoidea Lamarck 1809 clam
 Pectinida - Neitheoidae
"Neithea cf. shawi" = Neithea (Neithea) coquandi
"Neithea cf. shawi" = Neithea (Neithea) coquandi Peron 1877 scallop
 Ostreida - Ostreidae
Ostreidae indet. Rafinesque 1815 oyster
Echinoidea
 Irregularia -
Holasteroida indet. Durham and Melville 1957 sea urchin
Spatangoida indet. Agassiz 1840 heart urchin
Coccolithophyceae
 Braarudosphaerales - Polycyclolithaceae
"Lithastrinus floralis" = Eprolithus floralis
"Lithastrinus floralis" = Eprolithus floralis Stradner 1962
 Eiffellithales - Chiastozygaceae
Loxolithus armilla Black 1959
 Prymnesiophycidae - Prymnesiophycidae
 Stephanolithiales - Parhabdolithaceae