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CRETACEOUS-TERTIARY (K/T) MASS EXTINCTION: EFFECT OF GLOBAL CHANGE ON CALCAREOUS 82 MICROPLANKTON (top of P1a) that marks the initial recovery of the ecosystem at El Kef (Figure 4.9). The N. parvulum abundance peak is followed by abundance peaks in Futyania petalosa (Toweius petalosus), Praeprinsius of P. dimorphesus, and Octolithus multiplus (Perch-Nielsen, 1981). Caravaca, Spain The planktic foraminiferal assemblages that dominate during the latest Maastrichtian at Caravaca (as well as Agost) are similar to those at El Kef, although species abundance varies significantly (Figure 4.10; Canudo et al., 1991). The K/T boundary is characterized by the same species datums as well as lithological and geochemical markers (Robin et al., 1991), but the boundary clay is much thinner (7 cm) than at El Kef (50 cm). Species abundances are variable across the boundary. Heterohelix navarroensis, H. glabrans, and H. globulosa decline in abundance 5 to 10 cm below the boundary, whereas H. globulosa, Pseudotextularia costulata, P. kempensis, Globigerinelloides aspera, and G. yaucoensis remain the same or increase in the boundary clay. All Cretaceous species, except G. cretacea, decline to <2% immediately above the clay layer. As indicated earlier, this sharp faunal change marks a short hiatus (Figure 4.3), and part of the anomalous abundance increase in P0 may be due to reworking of Cretaceous taxa. Nevertheless, these relative abundance changes suggest ecological disturbances beginning prior to the K/T boundary and continuing into the earliest Tertiary (7-cm clay layer). At Caravaca and El Kef, similar sequences of rapidly evolving and changing dominant planktic foraminiferal components are present in the earliest Tertiary, including the maximum abundances of P. longiapertura, P. eugubina, and Woodringina (Canudo et al., 1991). However, because the earliest Tertiary at Caravaca is more condensed Figure 4.10 Percentage CaCO3, Î´13C values, and abundance of dominant planktic foraminiferal species (percent) across the K/T boundary at Caravaca, SE Spain. Note the presence of abundant Cretaceous specimens in the boundary clay (Zone P0).