Abstract: Salt-Related Fault
Families and
Fault
Welds in the
Northern Gulf of Mexico
ROWAN, MARK G. and BRUCE D. TRUDGILL, 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 asym-metric 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 down-slope
movement. These linked
fault
systems are directly related to five
types of salt systems: autochthonous, stepped counter-regional,
roho, salt-stock canopy, and salt nappe.
AAPG Search and Discovery Article #90937©1998 AAPG Annual Convention and Exhibition, Salt Lake City, Utah