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Abstract:
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This study provides new insights on the mechanisms that controlled the development of solution -enhanced fractures and suprastratal deformation associated with the Mississippian Madison Sequence IV evaporite paleokarst complex . Based on detailed field mapping utilizing LiDAR , GPS , and field observations , we document a paleostructural high (oriented 145º ) associated with the Ancestral Rockies uplift within the study area . One hundred twenty -one sediment -filled , solution -enhanced fractures within the Seq . IV cave roof were mapped and characterized by their dominant fill type (Amsden or Madison ) and vertical extent . Spatial analysis reveals minimum spacing of these features occurs in areas uplifted during the Late Paleozoic suggesting a link between paleostructural position and solution feature spacing . Shape analysis of these solution features also supports structural position during the Late Paleozoic acted as a dominant control on fracture morphology : (1 ) downward tapering and fully penetrative features concentrate in areas that experienced uplift ; (2 ) upward tapering concentrate in areas that were undeformed . Mapping of Seq . IV cave roof strata demonstrates vertical collapse variability exceeds 22 m and fault intensity increases in areas of increased collapse . These findings have significant implications for prediction and characterization of solution -enhanced fractures and suprastratal deformation within evaporite paleokarst systems . |