3D Geological Characterization of Proximal Mississippian Mounds in the Sacramento Mountains, Southern New Mexico

摘要

The Mississippian strata (Lake Valley Formation, Fm) in the Orogrande Basin in southern New Mexico are well known for their Walsortian mud mounds (Ahr, 1989; Hunt, 2000; Jeffery and Stanton, 1996; Kirkby and Hunt, 1996; Laudon, 1941; Pray et al., 1977). These mounds show a range of size and architectural elements along the depositional ramp, dip profile (Fig. 1). In the updip part of the exposed profile are several small amalgamated mound complexes while in the downdip part are large and isolated mounds. The updip amalgamated mounds are very well persevered in the Indian Wells canyons where they are exposed along several parallel canyons and are the objective of this study. In this paper we are investigating the mounds 3D geometry, internal architecture (i. e., dimensions, flank symmetry or asymmetry) and spatial distribution using the exposures along parallel canyon walls an extrapolating to covered or eroded areas. The uncertainties in the extrapolation is a three dimensional problem that needs to integrate all outcrop information into a well constrained georeferenced framework and the use of geostatistical approaches. Further, we examine the relation between the positions of mounds to antecedent topography.