Pacific Coast Coccolith Stratigraphy between Point Conception and Cabo Corrientes, Deep Sea Drilling Project Leg 63

Abstract

DSDP Leg 63 recovered Neogene coccoliths from south of Point Conception, California (Site 467), to north of Cabo Corrientes, Mexico (Site 473), as part of a traverse exploring the sedimentary record of the California Current along the Pacific Coast. A combination of temperate and tropical zonations were used to date Leg 63 coccolith assemblages because of intergradations of warm and cool species along the transect. Variations in the abundance and the presence and absence of Discoaster species are useful in recognizing warm-cool intergradations. New taxa described in this report include Discoaster okadai n. sp., D. sanmiguelensis n. sp., Helicosphaera californiana n. sp., H. crouchii n. sp., H. gertae n. sp., and H. vedderi n. sp.

Neogene geohistory analysis of Santa Maria Basin, California, and its relationship to transfer of Central California to the Pacific Plate. Diatom biochronology of the Sisquoc Formation in the Santa Maria Basin, California, and its paleoceanographic and tectonic implications

“…Age estimates for older diatom zones are mostly derived through indirect correlation to paleomagnetic stratigraphy and (or) radiometric ages (Barron, 1986a(Barron, , 1992a. The radiolarian zonation of Weaver and others (1981) and the calcareous nannofossil zonation of Okada and Bukry (1980) as recognized by Bukry ( , 1981 off California are correlated to the diatom zones after Barron (1986aBarron ( , 1992a. Low diversity and low abundance of agediagnostic calcareous nannofossil taxa prevents further subdivision of the calcareous nannofossil zones.…”

Magnetobiostratigraphic Synthesis of Leg 123: Sites 765 and 766 (Argo Abyssal Plain and Lower Exmouth Plateau)

“…Cenozoic calcareous nannofossil zonations used during Leg 123 include Gartner (1977) for the Pleistocene and Martini (1971), Okada and Bukry (1980), and Bukry (1981) for the remainder of the Cenozoic. All zonations were reasonably applicable to the eastern Indian Ocean and, where usable, Okada and Bukry's zonation was preferred over Martini's zonation because of its higher resolution.…”

“…Both nannofossils and planktonic foraminiferal assemblages display a temperate, or mid-latitude, nature. For example, the mid-latitude Amaurolithus delicatus Subzone (CNlOd) of Bukry (1981) could be applied, and Globorotalia puncticulata, a good marker species in the northern Atlantic Ocean, is common in the Pliocene. Unfortunately, rotary drilling in the upper portion of the hole disrupted the sedimentary fabric and reset the magnetization.…”

“…The corecatcher sample belongs in the Amaurolithus delicatus Subzone (CNlOd) of Bukry (1981), based on the common co-occurrence of Discoaster asymmetricus and Amaurolithus delicatus. The foraminiferal assemblage contains Globorotalia puncticulata (including morphotypes transitional to G. inflata), G.…”

Late Neogene Calcareous Nannofossil Biostratigraphy and Paleoceanography of ODP Hole 677A, Panama Basin

“…The highest occurrence of Discoaster surculus occurs in Sample 111-677A-13H-CC, whereas the highest occurrence of both Discoaster tamalis and Discoaster decorus occurs between Samples 111-677A-14H-3, 25 cm, and 111-677A-14H-CC. In the zonation of Okada and Bukry (1980) Bukry (1973) at Deep Sea Drilling Project (DSDP) Site 157 in the Panama Basin, where the species consistently occurs in the D. tamalis Subzone, with only rare occurrences in adjacent sub zones.…”