Ages, biostratigraphic datums, and coiling ratios of Pulleniatina in sediments from DSDP Holes 15-154A and 16-157 ...

• Main Author: Keigwin, Lloyd D
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA 1978
• Subjects: Drilling/drill rig; Leg15; Leg16; Glomar Challenger; Deep Sea Drilling Project DSDP; Neogloboquadrina pachyderma
• Online Access: https://dx.doi.org/10.1594/pangaea.722569; https://doi.pangaea.de/10.1594/PANGAEA.722569

Pliocene and Pleistocene planktonic foraminiferal biogeography and paleoceanography have been examined in Deep Sea Drilling Project (DSDP) sites of the Panama Basin (Pacific Ocean) and Colombian and Venezuelan Basins (Atlantic Ocean) to determine the timing of the isolation of Atlantic and Pacific tropical planktonic faunas resulting from the development of the Central American isthmus. Previous studies have suggested a late Miocene to middle Pliocene occurrence of this event. The Panama Basin (DSDP site 157) and the Colombian Basin (DSDP site 154A) share two early Pliocene biogeographic events: (1) great abundance of sinistral coiling Neogloboquadrina pachyderma at 4.3 m.y. ago at site 157 and 0.7 m.y. later at site 154A, and (2) a sinistral-to-dextral change in the coiling-direction preference in Pulleniatina 3.5 m.y. ago at both locations. Identification of these events farther to the east in the Venezuelan Basin (DSDP site 148) is complicated by insufficient lower Pliocene core recovery, but abundant ... : Supplement to: Keigwin, Lloyd D (1978): Pliocene closing of the Isthmus of Panama, based on biostratigraphic evidence from nearby Pacific Ocean and Caribbean Sea cores. Geology, 6(10), 630-634 ...