96-3 The Burial Wedge Concept – New Understandings of the tops of Diapirs.

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

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Abstract:

In studies spanning 10 years, the Integrated Institute of Tectonic Studies group at UTEP has recognized new processes and structures related to the end of diapirism. Although our research has been concentrated in the Paradox Basin of Utah and Colorado, burial wedges have been recognized in salt basins around the world and allow reinterpretation of the histories of diapirism and deformation.  We now know that many diapirs do not just rise and then are buried.  Rather, parts of the diapirs are buried, while diapirism continues in adjacent areas. This creates partial roofs that are subject to deformation during and after deposition and can vary widely in age from one part of a diapir to another. Many interpretations of exposed diapirs have inferred solution blocks faulted into the diapir with roots surrounded by caprock. Recognition of burial wedges shows that these are actually in situ wedges of sediment, deposited on the caprock. This reinterpretation recognizes that many structures, originally identified as faults, are instead burial wedge strata folded over diapiric caprock.  Strata on burial wedges commonly contain clasts derived from the adjacent diapir as it is exposed during its continued rise. Debris flows show that the diapir may have maintained a steep topographic high. Furthermore, burial wedges exhibit qrowth strata and syndepositional folding, in a few diapirs, documenting compression, probably gravity driven from topographically high diapir adjacent to the burial wedge. Almost universal are syndepositional microbasins that fold burial wedge strata. In various basins, this has previously been interpreted as post-diapiric tectonism or solution collapse deformation. Burial wedges highlight the dynamic interplay of halokinetic deformation and sedimentation that the ITS group has explored.

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

doi: 10.1130/abs/2025AM-8514

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