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Closure of the Central American seaway was a local tectonic event with potentially global biotic and environmental repercussions. We report geochronological (six U/Pb LA‐ICP‐MS zircon ages) and geochemical (19 XRF and ICP‐MS analyses) data from the Isthmus of Panama that allow definition of a distinctive succession of plateau sequences to subduction‐related protoarc to arc volcaniclastic rocks intruded by Late Cretaceous to middle Eocene intermediate plutonic rocks (67.6 ± 1.4 Ma to 41.1 ± 0.7 Ma). Paleomagnetic analyses (24 sites, 192 cores) in this same belt reveal large counterclockwise vertical‐axis rotations (70.9° ± 6.7°), and moderate clockwise rotations (between 40° ± 4.1° and 56.2° ± 11.1°) on either side of an east‐west trending fault at the apex of the Isthmus (Rio Gatun Fault), consistent with Isthmus curvature. An Oligocene‐Miocene arc crosscuts the older, deformed and segmented arc sequences, and shows no significant vertical‐axis rotation or deformation. There are three main stages of deformation: 1) left‐lateral, strike‐slip offset of the arc (∼100 km), and counterclockwise vertical‐axis rotation of western arc segments between 38 and 28 Ma; 2) clockwise rotation of central arc segments between 28 and 25 Ma; and 3) orocline tightening after 25 Ma. When this reconstruction is placed in a global plate tectonic framework, and published exhumation data is added, the Central American seaway disappears at 15 Ma, suggesting that by the time of northern hemisphere glaciation, deep‐water circulation had long been severed in Central America.

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The emergence of the Central American isthmus occurred episodically from Eocene to Pliocene time and was caused by a series of tectonic and volcanic processes. Results from zircon U‐Pb geochronology, zircon (U‐Th)/He (ZHe) and apatite (U‐Th)/He (AHe) thermochronology, and zircon Lu‐Hf isotopic data from sedimentary (sandstones and recent river sands) and plutonic rocks from the Azuero Peninsula and Central Panama document the exhumation and uplift history of the Panamanian basement complex. Our data support previous paleobotanical and thermochronological studies that suggest that by middle Eocene time some areas of Central Panama and Azuero Peninsula were exposed above sea level as a series of islands surrounded by shallow open marine waters. The Gatuncillo, Cobachón and Tonosí formations were deposited during this partial emergence. Transtension in the Oligocene‐early Miocene produced various pull‐apart basins (e.g., the Canal Basin) and local uplift that exhumed the Eocene strata (Gatuncillo and Cobachón formations). This event probably reduced circulation between the Pacific Ocean and the Caribbean Sea. The Tonosí Formation records late Miocene to Pleistocene cooling and exhumation, which may be related to uplift above the subducting Coiba Ridge. These results suggest that the emergence of the Isthmus of Panama followed a series of diachronous events that led to the final closure of the Central American seaway.

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