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Kinematic 3-D Analysis of Dina Field Structure from Growth Strata Patterns, Neiva Sub-Basin, Upper Magdalena Valley, Colombia

Pedro Alejandro Galindo1 and Freddy Corredor2
1 Universidad Nacional de Colombia, Bogotá D. C, Colombia
2 Harvard University, Cambridge, MA

We use the patterns of growth sedimentation above the frontal and backlimbs of the Dina field structure, located in the western fold and thrust belt of the Upper Magdalena Basin, Colombia to describe the 3D kinematic evolution of this fault-related fold. This large structure has a maximum structural relief of 850 m above the western flank of the Neiva Sub-basin (Central Cordillera foothills) where syntectonic sedimentation has occurred since the Miocene and is active today (Barzalosa and Honda Formations). Through the structural interpretation of a depth converted 3D seismic volume in the Neiva sub-basin, and using quantitative fault-related folding theories we describe the main folding mechanisms for the Dina Anticline. The Dina Anticline is described as a complex wedge formed by the Bache and Dina east verging thrust faults. The seismic interpretation of the frontal and backlimbs of the Dina Anticline, assisted with well logs data, resulted in the mapping of inflection points of inactive axial surfaces across growth strata, which define the relative timing of thrusting and the kinematics of structural growth. These maps show the differences along the strike in relative timing of formation of the fold and fault propagation. Maps of inflection points of inactive axial surfaces are an efficient new method of defining the structural fold evolution in three dimensions, and the direction of fault propagation in an environment of syntectonic sedimentation.