39 Structural Geology (Posters)

Added due to amount of discipline abstracts submitted.

Wednesday, 11 March 2026
9:00 AM - 12:00 PM
RCC, Lower Level Hall

Folding and Boudinage in Interbedded Salt: Insights from Scaled Experimental Models

Paper number: 39-6
Program: Technical Sessions
Time: 9:00 AM – 9:00 AM

Authors

Abstract

Many salt-rich sedimentary basins (e.g., onshore Texas and offshore eastern Canada and Brazil) contain not only rock salt (i.e., halite) but also interbedded brittle sedimentary rocks such as shales, carbonates, or other evaporites. This study investigates how the thickness and stratigraphic position of these brittle internal layers affect deformation patterns within salt using a series of scaled experimental models. In all models, alternating layers of silicone putty and wet clay or dry sand represent viscous salt and brittle interbedded layers, respectively. To trigger deformation, we place a narrow wedge of wet clay or dry sand above the layered models to simulate depositional loading. This loading produces a minibasin, causing lateral flow of the underlying putty away from the load. In all models, internal brittle layers beneath the depositional load undergo extension and form boudins, while a broad shortening domain develops adjacent to the minibasin. In this shortening region, the putty thickens and internal brittle layers undergo shortening, producing buckle folds. Our preliminary results indicate that both the relative thickness and depth of the brittle internal layers significantly influence fold style and intensity. Models with relatively thin brittle internal layers (>25% of the total thickness) develop numerous folds with variable geometries, ranging from gentle upright folds to tight and overturned folds. Many tight folds are disharmonic and asymmetric, with steeply dipping overturned limbs that verge away from the minibasin. In contrast, models with relatively thick brittle internal layers (>25% of the total thickness) produce only a few gentle, upright folds. Additionally, models with either shallow or deep internal layers develop fewer folds, suggesting that folding is most intense when the internal brittle layers are in an intermediate stratigraphic position. Sand models produce slightly more folds than clay models, indicating a higher ductility contrast between the interbedded layers and salt may enhance folding. These results provide new constraints on the structural evolution of interbedded salt and have direct implications for interpreting deformation in salt-bearing sedimentary basins worldwide, including the Orpheus rift basin, offshore eastern Canada, and other basins where intrasalt rocks serve as hydrocarbon reservoirs or sites for underground gas storage.

Geological Society of America Abstracts with Programs. Vol. 58, No. 1

doi: 10.1130/abs/2026SE-411744

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