See more from this Division: Topical Sessions
See more from this Session: Brittle Deformation and Diagenesis as Coupled Processes
Wednesday, 8 October 2008: 11:35 AM
George R. Brown Convention Center, 320ABC
Abstract:
Knowledge of the history of structurally-influenced fluid flow and diagenetic processes within sandstone deposits can provide important information on the deposits' function as reservoirs for hydrocarbons, their potential for economic minerals, and overall understanding of basin evolution and burial history. Imaging spectroscopy provides a valuable tool for mapping surface patterns of authigenic mineralogy in exposed sedimentary rocks. The early Jurassic Navajo Sandstone is a thick, porous, and permeable eolian unit prominently exposed throughout southern Utah. Typical Navajo Sandstone is ~90% quartz, a mineral which lacks any significant absorption features in the VNIR/SWIR wavelength region. This detrital composition, with spectrally bland background as well as extensive surface exposure, allows for spectral identification and regional mapping of minor secondary cements such as carbonate, clays, iron oxides, and sulfates. Kavaicuwac (aka Mollies Nipple) is an anomalous jarosite-cemented butte of Navajo Sandstone in Grand Staircase Escalante National Monument. This site is of particular interest for understanding the history of fluid flow and chemical diagenesis in this area, due to its unique mineralogical and geomorphic characteristics. One hypothesis for the unusual nature of this site is that Kavaicuwac experienced alteration related to fluid flow at the intersection of multiple faults. Field observations, classification of data acquired from two aerial hyperspectral sensors (HyMap covering the VNIR/SWIR, and SEBASS covering the LWIR), evaluation of in situ spectral data, combined with petrographic, mineralogical, and geochemical analyses are being used to examine the diagenetic history of this site. This site is compared to other structurally-influenced diagenetic features elsewhere in the Navajo Sandstone to address the range of geochemical conditions that have existed in this reservoir over time and the benefit of investigating structural diagenesis with imaging spectroscopy.
See more from this Division: Topical Sessions
See more from this Session: Brittle Deformation and Diagenesis as Coupled Processes
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