192-2 The Influence of Salt Structures and Associated Strata on Local and Regional Paleofluid Migration in the Paradox Basin, USA

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

Presenting Author:

Authors:

Abstract:

Paleofluid migration in the Paradox Basin was complex due to the presence of salt tectonics, which progressively altered the paleofluid system through changes in the 3-D distribution of low-permeability, evaporitic strata of the Pennsylvanian Paradox Formation, as well as the distribution of overlying Pennsylvanian through Jurassic strata. The thickness, facies patterns and spatial distribution of these later units were particularly impacted by the growth of salt walls in the northeastern part of the Paradox Basin. Because of the high thermal conductivity of evaporites, these salt walls are also likely to have altered the thermal structure of the basin, locally adding a thermal convective influence on whatever regional topographic head gradients may have been driving fluid migration in the basin. Given that Paradox Basin oil and gas accumulations and mineral deposits like copper, uranium and vanadium are spatially correlated with salt walls, it is useful to constrain how the fluid system changed in response to the salt tectonic evolution of the basin.

In this study, we use 2-D finite element modeling to examine the connection between salt walls and paleofluid migration in the Paradox Basin.  We first employed simple, rectangular models with a single layer of salt of varying geometry to study the influences of lateral changes of salt thickness. We then used published, 2-D cross sections restored to the Permian and Cretaceous to capture the evolution of salt structures to examine the paleohydrological changes that were brought about as a result of changes in the geometry of salt walls and the nearby, halokinetically deformed strata.

Our models demonstrate the development of thermal convection is related to the thickness of non-salt sedimentary rock. Where salt is thin and the non-salt rock is thicker, there is an increase in convection. The presence of a horizontal layer of salt creates two separate fluid systems, where convection may occur independently above or below salt. When salt is thin and creates a salt weld, the fluid systems may become linked and allow fluid to migrate between systems that were once separate. In the presence of salt structures, a lower temperature zone is observed in the non-salt rock below the diapir, likely associated with the thermal conductivity of salt transporting heat up the diapir faster than surrounding rock.

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

doi: 10.1130/abs/2025AM-5477

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