--> Axial Versus Marginal Sediment Systems in Rift Basin Settings

2018 AAPG International Conference and Exhibition

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Axial Versus Marginal Sediment Systems in Rift Basin Settings

Abstract

Works by Gupta et al., 1998; Ravnås and R. J. Steel, 1998; Gawthorpe, 2000; Cowie et al., 2000; Leeder and Mack, 2007 have made significant contributions towards the study of rift basins; recognizing the interplay between extensional tectonics, climate and sedimentary fill. Recent global exploration has highlighted our need to understand both deposition and preservation in modern day continental rift basins. As a result, this body of work aims to more clearly differentiate the stratigraphic architecture of rifts, by documenting how basin fill is impacted spatially and temporally during the different phases of rifting, to assess the petrographic nature and reservoir potential of modern day continental rifts. The Espanola basin of the Rio Grande rift New Mexico, U.S. is a Tertiary age sub-basin that provides an excellent outcrop analog for studying synrift fills in continental rifts. Outcrop sections were measure, described and sampled to document the Santa-Fe, syn-rift sediments of the Espanola toward an assessment of the nature of marginal to axial sediment development. Preliminary analysis shows from margin to axis sediments are generally younger, finer grained, better sorted, with occasional abrupt facies change. Bed thickness and vertical changes in stratigraphy indicate that the basin experienced significant variations during deposition. Overall, this research seeks to implement such observations to compare the stratigraphic architecture in fluvial dominated rift basins to test the ideas of linkages between fluvial morphology, fill architecture and composition; and contribute to a deeper understanding of rift basin evolution in order to develop more comprehensive stratigraphic frameworks.