Browsing by Subject "McKittrick Canyon"
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Item Airborne lidar-aided comparative facies architecture of Yates Formation (Permian) middle to outer shelf depositional systems, McKittrick Canyon, Guadalupe Mountains, New Mexico and west Texas(2010-12) Sadler, Cari Elizabeth; Kerans, C. (Charles), 1954-; Steel, Ronald; Fisher, WilliamThe eastern side of the Guadalupe Mountains, located in New Mexico and west Texas, represents an erosional profile along the Capitan reef margin. A complete shelf-to-basin exposure of the Upper Permian Capitan shelf margin is found on the north wall of North McKittrick Canyon, which is nearly perpendicular to the Capitan reef margin. An excellent 2-D sequence stratigraphic framework for upper Permian backreef facies has been developed by previous workers for North McKittrick Canyon (Tinker, 1998) and Slaughter Canyon (Osleger, 1998), forming the basis for observations in this study. The goal of this study is to describe the sequence stratigraphic architecture of the Yates Formation, focusing on the Y4-Y6 high-frequency sequences (HFSs) found in the middle to outer shelf depositional systems, and to illustrate the use of airborne lidar data to quantitatively map at the cycle-scale. Seven measured sections were taken in North McKittrick Canyon. From airborne lidar, 3-D geometries of key sedimentary and structural features were mapped in Polyworks, in addition to the sequence boundaries delineating the Yates 4-6 HFSs. In general, major cycles exhibit asymmetry and shoal upward. Cycle boundaries are sometimes hard to delineate due to amalgamation, particularly in the shelf crest. High-frequency sequences are commonly asymmetric; they deepen and thicken upward toward the maximum flooding surface, and the boundaries between HFSs are usually marked by thick siltstones. Major HFS boundaries can be mapped across the entire dataset, and some component cycles can be observed for minimum distances of one kilometer in an updip-downdip direction. Also, some facies tract dimensions can be estimated directly from the lidar data. Measured sections indicate that the shelf crest facies tract shifts seaward with each successive HFS, while the outer shelf facies tract steps landward. Future work that could be done with the Y4-Y6 HFSs includes 8-10 more measured sections, collection of samples for thin sections, and tracing out of contacts between facies tracts. Extensive lidar data interpretation needs to be done so that digital outcrop models demonstrating facies distributions can be produced. This would enable the development of an outcrop analog model to mixed carbonate-siliciclastic reservoirs, which would be unprecedented in this area.Item Anatomy, dimensions, and significance of the penultimate Yates tepee-shelf crest complex, G25 Hairpin HFS, Guadalupe Mountains, New Mexico and Texas(2016-05) Voorhees, Kristopher James; Kerans, C. (Charles), 1954-; Janson, Xavier; Fisher, William L.The steep-rimmed Permian Capitan platform in the Guadalupe Mountains has been studied in extensive detail to understand the effect of eustacy on platform architecture as seen in continuously exposed 700 m relief shelf-to-basin depositional profile. The Guadalupian Hairpin member (G25 High-Frequency Sequence) of the Yates Formation represents a major regional shelf marker and displays continuous 2.5 km dip-width exposures of the Capitan platform in McKittrick, Big, Double, Gunsight, Slaughter, Rattlesnake, and Walnut Canyons. Compared to the sequences above and below it, the G25 HFS is unique in that it reveals pronounced expansion of the shelf crest tepee-pisolite complex from an average of 1 km width to greater than 2 km. Tepee structures are 2-20 m diameter expansion megapolygons with compressional ridges formed by syndepositional expansive crystallization of micritic cement in arid to evaporitic supratidal settings. Increased dip-width of the shelf crest tepee-belt reflects a prolonged period where repeated cycles of wetting, evaporation, precipitation, and buckling of storm-ridge washover facies (grainy tidal flats/beaches) dominated the shelf. This study seeks to examine the role that eustacy/accommodation play in expansion of the shelf crest tepee complex by quantifying the dimensions of Capitan-equivalent shelf facies in McKittrick and Rattlesnake Canyons. Dip-oriented regional cross sections in Rattlesnake and McKittrick Canyons were created from 21 measured sections from 50-500 m spacing covering 30 to 70 m in thickness calibrated to 3 high-resolution gigapan photomosaics that are in turn constrained spatially using airborne lidar data. Cross sections in both canyons constrain facies tract dimensions as well as depositional topography and spatial distribution of the tepee complexes, allowing construction of a new tightly controlled depositional profile. 29 thin sections aid in grain identification, cement composition, and facies classification. Two main results of this study are (1) a new tightly constrained model for the Capitan shelf unequivocally showing that the tepee-belt is the topographic high-point of the profile, and (2) the Hairpin G25 highstand marks a period of prolonged supratidal exposure of the shelf and rapid volumetrically significant marine cementation from a supersaturated fluid, marking the first phase of silling of the Delaware Basin and onset of basinal restriction prior to end-Capitan Castile evaporite deposition.