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Advancements in the Integrated Stratigraphic and Structural Model of the Guadalupian Mixed Clastic-Carbonate Model, Guadalupe Mountains, New Mexico

Abstract

An emphasis on developing an integrated stratigraphic and structural model of the Capitan shelf margin has driven rapid development of important new insights on syndepositional faulting, fracturing, and early through late diagenesis. In the past decade the acquisition of extensive airborne lidar as well as ground-based differential GPS and Gigapan mapping templates has fostered detailed comparisons within a common framework. The recognition of shelf-edge proximal early-formed, syndepositional faults and the potential impact these features have on facies patterns, stratigraphic architecture, syn- to post-depositional diagenetic fluid movement and subsequent rock property modification (e.g. early marine cementation, dolomitization, and dissolution) is a central development that contradicts earlier models. A 3D model of the Capitan shelf margin system has been of the Guadalupian 24 through 30 high frequency sequences. Model dimensions are 35 km parallel to shelf margin, 4 km perpendicular, and 500 m in depth, focused around Rattlesnake and Walnut Canyons and Carlsbad Caverns. We have also utilized observations of the Capitan system exposed in McKittrick Canyon to develop a stratal form template for extending the sequence surfaces and faults into the subsurface while honoring the locally mapped outcrop contacts and observations. The variability of several key fault systems associated with gravitational collapse of the shelf margin that develop contemporaneous with or soon after deposition are highlighted. Fault systems have 10s m of offset and are expressed as fault relays with variable fault length traces and offset. In addition, numerous early formed fractures develop along the margin, have limited offset, but often laterally extend 100s of m. While the local variability of faults and fracture systems is high, the role of pre-existing early cemented margins to concentrate the shelf-margin fractures and fault systems is clear and is reflected in the outcrop exposures and the developed model.