Abstract: Salt-Related Fault Families and Fault Welds in the Northern Gulf of Mexico

Rowan, M. G. - University of Colorado at Boulder; Jackson, M. P. A. - University of Texas at Austin; Trudgil, B. D. - University of Colorado at Boulder

We present and illustrate a new classification for salt-related faults and fault welds in the Gulf of Mexico that is based on the three-dimensional geometry of the faults, deformed strata, and associated salt. Families of extensional faults comprise symmetric arrays (peripheral, crestal, keystone) and asymmetric arrays, where the dominant direction of fault dip is basinward (roller, ramp, shale-detachment), landward (counter-regional), or variable (flap, rollover). We also illustrate contractional fault families (toe-thrust, break-thrust) and strike-slip families (lateral, tear). Finally, various fault welds (primary, roho, counter-regional, bowl, thrust, wrench) are surfaces representing evacuated salt bodies along which there has been significant slip.

Groups of fault families and fault welds are kinematically and genetically linked. Linked fault systems may contain extensional, contractional, strike-slip, salt, salt weld, and fault weld components. Extensional fault families are formed by basinward translation, subsidence into salt, or folding. Those that accommodate lateral translation may be balanced by salt extrusion and/or contractional fault families. Strike-slip fault families bound or segment areas with different magnitudes of downslope movement. These linked fault systems are direcdtly related to five types of salt systems: autochthonous, stepped counter-regional, roho, salt-stock canopy, and salt nappe.

AAPG Search and Discovery Article #90933©1998 ABGP/AAPG International Conference and Exhibition, Rio de Janeiro, Brazil