The Oligocene-Miocene collision between Panama and South America significantly influenced ocean currents, global climate, and species diversification. Intraplate deformation of the
Panama Block also played an important role in the evolution of this tectonic system, but is not well understood. A high-resolution gravity survey, coupled with geologic observations, was
conducted in north-central Panama to better constrain the processes responsible for the Isthmus' modern configuration. Approximately 110 gravity stations were collected from Colón to
Nombre de Dios, Panama and merged with existing data. Subsequently, four 2.5-D gravity models were produced to constrain the geometry of the Gatun-Chagres Basin using different sedimentary
densities (1.8, 2.0, and 2.2 g/cm3) to produce a realistic range of basin thicknesses. Overall, models with an average basin density of 2.0 g/cm3 are most consistent with offshore seismic
profiles and field evidence, suggesting basin thickness is ~3.0-3.5 km. Previous seismic reflection data and geochemical analyses of Miocene arc volcanic rocks delineate a zone of
extension in the Panama Canal Region, and gravity analysis from this study supports this hypothesis. Field evidence of multiple NW-facing normal faults suggests that they separate the
basin from uplifted arc basement rocks east of the Canal, resulting in a 60 mGal gravity gradient. Beneath the basin, gravity models indicate ~5-10 km of crustal thinning. 3-D
reconstruction of the 2.5-D models show a northward thickening basin and two depocenters that correspond to the Rio Indio and Toro facies of the Chagres Formation. This analysis suggests
two directional extension of the Gatun-Chagres Basin; an east-west direction corresponding to the initial formation of the basin, and a modern northwest-southeast direction. To the
northeast, gravity modeling indicates that there is a ~150 m-thick, Cretaceous-Holocene sedimentary basin present from Portobelo to Nombre de Dios. Sedimentary units in the western part of
this basin exhibit large-scale open folds, which may indicate a transition from extensional to compressional tectonics east of the Panama Orocline Apex. The ongoing collision between South
America and the Panama Block also fractured the crust creating zones of extension in central Panama. Overall, gravity modeling suggests that low-density sedimentary rocks extend across the
Isthmus and south of the Gatun-Chagres Basin. Such results are consistent with the idea that the Panama Canal Region formed a young marine connection between the Caribbean Sea and Pacific
Ocean. / A Thesis submitted to the Department of Earth, Ocean, and Atmospheric Science in partial fulfillment of the requirements for the degree of Master of
Science. / Fall Semester 2015. / October 19, 2015. / Basin, Geophysics, Gravity, Modeling, Panama, Tectonics / Includes bibliographical references. / David W. Farris, Professor Directing Thesis; James F. Tull, Committee Member; Stephen Kish, Committee Member; Seth Young, Committee Member.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_291319 |
| Contributors | Mynhier, Kelci (authoraut), Farris, David W. (professor directing thesis), Tull, James F. (committee member), Kish, Stephen A. (committee member), Young, Seth Allen, 1978- (committee member), Florida State University (degree granting institution), College of Arts and Sciences (degree granting college), Department of Earth, Ocean, and Atmospheric Science (degree granting department) |
| Publisher | Florida State University |
| Source Sets | Florida State University |
| Language | English, English |
| Detected Language | English |
| Type | Text, text |
| Format | 1 online resource (65 pages), computer, application/pdf |
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