Cenozoic structural evolution of the eastern margin of the Middle Magdalena Valley basin, Colombia : integration of structural restorations, low-temperature thermochronology, and sandstone petrography

dc.contributor.advisorHorton, Brian K., 1970-en
dc.contributor.committeeMemberMann, Paulen
dc.contributor.committeeMemberKetcham, Richarden
dc.creatorSánchez, Carlos Javier, M.S. in geological Sciencesen
dc.date.accessioned2011-11-10T22:06:28Zen
dc.date.available2011-11-10T22:06:28Zen
dc.date.issued2011-08en
dc.date.submittedAugust 2011en
dc.date.updated2011-11-10T22:15:56Zen
dc.descriptiontexten
dc.description.abstractStructural analysis of surface and subsurface data from the Middle Magdalena Valley basin and Eastern Cordillera fold-thrust belt to construct a kinematic model for its Cenozoic structural and stratigraphic evolution. The La Salina west-vergent thrust system marks the boundary between the Paleogene foreland basin of the Middle Magdalena basin and the Eastern Cordillera fold-thrust belt. New low-temperature thermochonological and sandstone petrographic analyses provide constraints on ages of thrust deformation and sediment dispersal. Apatite fission track (AFT) and U-Th/He thermochronological results show the timing of three structural events along the La Salina fault system: (1) late Eocene-early Oligocene (~43–35 Ma) initial hanging wall exhumation; (2) continued middle Miocene (~15 Ma) exhumation; and (3) continued but more rapid late Miocene (~12–3 Ma) hanging wall exhumation. Vitrinite reflectance results provide estimates of maximum burial depths for the hanging wall of the La Salina fault ranging from 4 to 6 km., this depth of burial estimates constrain the basin geometry during its late Eocene to late Miocene evolution. The eastern hanging wall of the La Salina fault displays a broad anticline-syncline pair affecting Cretaceous to Eocene strata with no significant faulting, whereas the western footwall contains a complex series of tight, thrust-related folds in Eocene-Quaternary strata. For foreland basin province, a proposed triangle zone accommodates a small amount of east-west shortening (< 1000 m) along the frontal thrust system by east-vergent backthrusting within a broader passive-roof duplex. East-west shortening in the Cenozoic stratigraphic section was also accommodated by detachment folding, which produced localized areas of steep dips. In the proposed kinematic restoration, the most recent phase of deformation represents out-of-sequence reactivation of the La Salina fault that is consistent with irregular crosscutting relationships of some footwall structures. Earliest exhumation by ~45–30 Ma in the Eastern Cordillera fold-thrust belt province matches (1) an increased proportion of sedimentary lithic fragments; and (2) a high degree of compositional maturity (Q88F4Lf8). Exhumation since ~15 Ma in the foreland province coincides with (1) the highest accumulation rates observed for the upper Miocene Real Group; and (2) a decrease in compositional maturity (Q55F8Lf36).en
dc.description.departmentEarth and Planetary Sciencesen
dc.format.mimetypeapplication/pdfen
dc.identifier.slug2152/ETD-UT-2011-08-4185en
dc.identifier.urihttp://hdl.handle.net/2152/ETD-UT-2011-08-4185en
dc.language.isoengen
dc.subjectMiddle Magdalena Valley Basinen
dc.subjectEastern Cordilleraen
dc.subjectColombiaen
dc.subjectStructural analysisen
dc.subjectThermochronologyen
dc.subjectSandstone petrographyen
dc.subjectKinematicsen
dc.subjectFold-thrust belten
dc.subjectLa Salina faulten
dc.titleCenozoic structural evolution of the eastern margin of the Middle Magdalena Valley basin, Colombia : integration of structural restorations, low-temperature thermochronology, and sandstone petrographyen
dc.type.genrethesisen
thesis.degree.departmentGeological Sciencesen
thesis.degree.disciplineGeological Sciencesen
thesis.degree.grantorUniversity of Texas at Austinen
thesis.degree.levelMastersen
thesis.degree.nameMaster of Science in Geological Sciencesen

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