Jgv. Widmark, Biogeography of terminal Cretaceous benthic foraminifera: deep-water circulation and trophic gradients in the deep South Atlantic, CRETAC RES, 21(2-3), 2000, pp. 367-379
The biogeographic distribution of terminal Cretaceous (late Maastrichtian)
deep-sea benthic foraminifera are analysed from the South Atlantic Ocean. T
he data quantified derive from six DSDP sites representing a west-to-east t
ransect in mid-latitudes and three high-latitude ODP sites.
Correspondence analysis revealed five benthic foraminiferal assemblages tha
t are representative of bathymetrically and latitudinally different environ
mental settings within the South Atlantic: (1) a Shallow Mid-Latitude Assem
blage [Bolivinoides draco, Eouvigerina subsculptura, Gaudryina pyramidata,
Scheibnerova? sp., Spiroplectammina spp. (calcerous forms) and Tritaxia asp
era]; (2) an Intermediate Mid-Latitude Assemblage [Cibicidoides hyphalus, N
uttallides truempyi, Paralabamina lunata, Praebulimina spp., Sitella cushma
ni and Valvalabamina sp. (involute form)]; (3) a Deep Mid-Latitude Assembla
ge (Bulimina velascoensis, Gyroidinoides beisseli, Nuttallinella sp. A. Ori
dorsalis-complex, Osangularia? sp., Paralabamina hillebrandti, Quadrimorphi
na camerata, Reussella szajnochae szajnochae and Sitella cf. plana); (4) a
Shallow High-Latitude Assemblage (Alabamina creta, Brizalina incrassata, Os
angularia texana, Pullenia coryelli, Pyramidina rudita and Spiroplectammina
'crassa'); and (5) a Deep High-Latitude Assemblage [Gavelinella beccariifo
rmis, Gyroidinoides quadratus, Nuttallides sp. A, Osangularia velascoensis,
Paralabamina sp. (intermediate form), Valvalabamina? praeacuta and Spiropl
ectammina dentata].
Comparison of the proportions of epibenthic/endobenthic morphotypes within
each of the five assemblages resulting from correspondence analysis suggest
s clear trends between sites of the mid- and high latitudes respectively, a
nd along bathymetric gradients among sites of similar latitudes. These tren
ds are inferred to represent environmental (such as trophic and oxygenation
) gradients when placed within a framework of hypothesized surface circulat
ion and upwelling patterns in the late Maastrichtian South Atlantic. (C) 20
00 Academic Press.