Closure of the Isthmus of Panama: the Near-Shore Marine Record of Costa Rica and Western Panama
Closure of the Isthmus of Panama: The near-shore marine record of Costa Rica and western Panama ANTHONY G. COATES* Department of Geology, The George Washington University, Washington, D.C. 20052 JEREMY B. C. JACKSON Smithsonian Tropical Research Institute, Box 2072, Balboa, Republic of Panama LAUREL S. COLLINS Museum of Paleontology, University of Michigan, Ann Arbor, Michigan 48109-1079 THOMAS M. CRONIN | HARRY J. DOWSETT | U.S. Geological Survey, 970 National Center, Reston, Virginia 22092 LAUREL M. BYBELL j PETER JUNG Naturhistorisches Museum, Augustinergasse 2, CH 4051, Basel, Switzerland JORGE A. OBANDO RECOPE, S.A., Apartado 4351, Zone 1000, San Jose, Costa Rica ABSTRACT sent on the Caribbean side. These sections was formed by northwestward movement of the fortuitously include abundant thick intra- South American plate (SO AM) and an easterly The final closure of the Isthmus of Panama formational slumps containing shallow-water vector of both the Nazca (NAZ) and Caribbean at ~3.5 Ma divided the American tropical fauna more appropriate for biological com- (C ARIB) plates that brought the Central Ameri- ocean into two separate and different oceano- parison with the Caribbean biota. Similarly, can volcanic arc in collision with the northwest graphic regions. Consequences for the marine the -1.9 Ma to 1.5 Ma interval, well con- South American foreland during the Neogene biota were profound, but, hitherto, correla- strained by various taxa, includes middle- to (Fig. 1). tion of the Pacific and Caribbean coastal sec- outer-shelf, and inner-shelf to upper-slope The timing and duration of closure of the tions has not been precise enough to track deposits on the Caribbean side, and marginal- Isthmus of Panama is known only in general biologic patterns.
[Show full text]