Giles, Katherine A.1, Timothy F. Lawton2, Mark G. Rowan3
(1) New Mexico State University, Las Cruces, NM
(2) Institute of Tectonic Studies, New Mexico State University, Las Cruces, NM
(3) Rowan Consulting, Inc, Boulder, CO
ABSTRACT: Halokinetic Sequences within a Depositional Sequence Stratigraphic Framework
Halokinetic sequences, common features in strata adjacent to salt diapirs, record the dynamic interplay of rising salt and local sediment accumulation. These growth-stratal packages are genetically influenced by near-surface or extrusive salt movement and form due to temporal variations in bathymetric relief over the diapir. Angular unconformities bounding the sequences form when net diapiric rise rate exceeds local sediment accumulation rate, allowing diapiric inflation at the surface to generate steep, unstable slopes upon which subjacent growth strata are truncated by either slope failure or erosion. Increasing local sediment accumulation rate relative to net diapiric rise rate results in onlap and overlap of strata onto the diapir. These burial processes suppress diapiric surface topography and erosion. Halokinetic sequence boundaries correspond to periods either of major increase in net salt rise rate or decrease in local net sediment accumulation rate regardless of depositional setting and potentially independent of regional base-level changes. Halokinetic sequences appear to form at the depositional sequence, systems tract, and parasequence-set scale of sediment accumulation variation. In the shelf environment, halokinetic sequences are more numerous and best developed during deposition of the transgressive systems tracts of second- and third-order depositional sequences when bathymetric relief develops due to relative sediment starvation. In basinal settings this corresponds to the maximum flood or early highstand systems tract. Within mini-basins, halokinetic sequence stratigraphy is superior to traditional depositional sequence stratigraphy for near-diapir stratal correlation and prediction of reservoir character and distribution.
AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.