96-8 Geological Investigation of the Salt Tectonic Features along the northwestern margin of Moab Valley Salt Wall, Paradox Basin

Session: Twenty-Seven Years of Advances in Understanding Salt-Sediment Interaction: A Legacy of Katherine A. Giles

Presenting Author:

Charles Igomu

Authors:

Igomu, Charles Ojodale¹, Brunner, Benjamin², Gannaway Dalton, Cora Evelyn³, Langford, Richard P.⁴, Salas Rivera, Paola⁵, Giles, Katherine A.⁶

(1) Department of Geological Science, University of Texas at El Paso, El Paso, TX, USA; Institute of Tectonics Studies/Salt-Sediment Interaction Research Consortium, El Paso, Texas, USA, (2) University of Texas at El Paso, Geological Sciences, El Paso, TX, USA; Institute of Tectonics Studies/Salt-Sediment Interaction Research Consortium, El Paso, Texas, USA, (3) Utah State University, PRICE, UT, USA; Institute of Tectonics Studies/Salt-Sediment Interaction Research Consortium, El Paso, Texas, USA, (4) Univ Texas - El Paso, El Paso, TX, USA; Institute of Tectonics Studies/Salt-Sediment Interaction Research Consortium, El Paso, Texas, USA, (5) The University of Texas at El Paso, El Paso, TX, USA, (6) University of Texas at El Paso, University of Texas at El Paso, El Paso, TX, USA; University of Texas at El Paso, Institute of Tectonics Studies, El Paso, Texas, USA,

Abstract:

This study investigates recently recognized salt-sediment interaction features such as burial wedges and non-evaporite inclusions/stringers in the area around the Moab Valley salt wall and also evaluates the potential southward continuation of a megaflap previously mapped approximately 1km north of the study area.

New geologic field mapping, petrographic and stratigraphic analysis, and drone imagery were integrated for this investigation. 161 petrographic samples were evaluated and utilized in tandem with stratigraphy to characterize the various carbonate lithofacies in the study area.

One of the study area’s most distinctive sedimentary features is a Triassic Chinle section that thins and wedges with angular unconformity toward the diapir. This section, located approximately 1.5 km south of the Colorado River, occupies about 200m wide folded zone. It includes a 4m thick, Upper Triassic bitumen-bearing lacustrine dolostone beds emplaced within sandstone beds of the lower slope forming member of the Chinle Formation. These strata are unconformably overlain by the informal black ledge unit. The observed thinning, wedging, and angular unconformity relationships toward the salt diapir indicate the presence of a burial wedge - a wedge-shaped accumulation of synkinematic strata that thins towards rising salt structure.

This geometry suggests progressive sedimentation during passive salt rise, where continued subsidence adjacent to the diapir accommodated deposition, while  diapir highs provided very little accommodation space for deposition. The burial wedge thus provides critical insight into the timing and dynamics of salt diapirism and the associated minibasin subsidence history. Several breccia pipes/chimneys are aligned along the fold axis within this burial wedge, suggesting structural control.

In addition, a steeply dipping, interbedded gypsum, shale, and dolostone succession on the southwest flank of Moab Valley was evaluated for its potential to be a megaflap based on previous mapping by Doelling et al (2002) and Trudgill (2011).  It was found to be highly fractured, extending about 110-meter, and contained disoriented deformation attributes more consistent with inclusions. By showing a lateral continuity much less than a kilometer before terminating under the younger Triassic Chinle sediments, we determined this unit ultimately falls short of the kilometer-scale requirement central to the megaflap definition.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-6527

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