Salt Sutures in
Single- and Multi-Tiered Allochthons,
Liro, Louis, RepsolYPF, The Woodlands, TX
Single-tiered allochthons originate
from Mesozoic salt layers. Such allochthons define
the present-day Sigsbee Escarpment in
Multi-tiered allochthons emanate from precursors at deeper levels. Across the study area, a consistent weld level at approximately 8 km depth suggests a pre-Miocene, extensive allochthon likely similar to the relatively undisturbed Miocene allochthon observed to the south. The multi-tiered allochthons have rugose tops, resulting in a poor subsalt image. They also display internal reflectors and complex suturing.
Extensive lateral sutures are observed both in single-tiered and multi-tiered salt regions. Lateral sutures in single-tiered allochthons are associated with feeder regions and parallel or diverge slightly from the base allochthon seismic event. These sutures are located in the lower third of the salt body, suggesting an early origin. In multi-tiered allochthons, the lateral sutures are observed at any height within the allochthon, and display less affinity to vertical salt sourcing regions. This relationship suggests that in the multi-tiered regions, “crowding” of allochthons, due to higher salt flux and secondary allochthon development, results in “pancaking” of salt allochthons, rather than lateral amalgamation.