96-1 The Early La Popa Years (1995–1998) of Dr. Katherine Giles: Springboard to Advanced Concepts in Salt-Sediment Interaction

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

Presenting Author:

Author:

Abstract:

The perspectives that Kate Giles derived from the study of evaporite diapirs in La Popa basin of northeastern Mexico—and along with her students subsequently exported to other localities the world over—have left an indelible and permanent impact on the field of sedimentation near structures formed by mobile evaporite ("salt"). The salt features of La Popa basin had been mapped and described by the mid-1980s, and although some were recognized to have had syndepositional growth, they were nevertheless categorized variously as piercement structures or as reverse faults that entrained gypsum and lost displacement laterally into bedding planes of adjacent strata. Shortly after arriving at New Mexico State University (NMSU), Kate cajoled a couple of colleagues to visit La Popa in January of 1995 with the idea of studying a classic foreland basin and lenticular carbonate strata, termed lentils, adjacent to salt bodies of the basin. On that trip, El Papalote diapir received its name and diapir-flanking growth strata in both carbonate lentils and siliciclastic intervals, although previously described, excited the interest of all involved. A year later, mafic igneous clasts derived from meter-scale blocks exposed in the diapir, as well as carbonate clasts and local gypsum fragments of diapiric provenance, were recognized in flanking siliciclastic strata, leading to the notion of syn-sedimentary diapir exposure during salt rise and to the concept of "diapir-derived detritus" (D³). By May 1996, it was recognized that the lentils, containing D³, formed the bases of unconformity-bounded carbonate-siliciclastic successions, which by the beginning of 1997 were termed halokinetic sequences. In a crowning achievement, following a semester break epiphany by Kate ("It's a weld!"), a 24-km-long planar discontinuity formerly regarded as a complex fault system was reinterpreted in January 1998 as an elongate salt weld, a former salt wall whose evaporite was mostly evacuated during subsidence of an adjacent minibasin. In 1998, a cascade of events attributable to Kate's energy and vision included development of a combined salt course and La Popa field excursion with Mark Rowan, initiation of the La Popa Joint Industry Consortium, the first such funding institute at NMSU, and acquisition of a field Suburban. The first industry-funded graduate students visited La Popa basin in September 1998, and the basin ultimately hosted twenty NMSU M.S. theses.

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

doi: 10.1130/abs/2025AM-8987

© Copyright 2025 The Geological Society of America (GSA), all rights reserved.