Mass transport deposits (MTDs) are commonly regarded as motionless evidences of past mass wasting events. Three-dimensional seismic surveys acquired offshore central Israel reveal continued long-lasting and even current deformation of >1.5 Myr old MTDs, now buried hundreds of meters beneath and still impacting the seafloor. Faulting and folding of the Messinian-Pliocene unconformity (M), at the base of the studied interval, represent the possible impacts of tectonic and halokinematic deformation. However, an ~200 m thick continuous stratified unit straddles the M and entirely separates the overlaying Plio-Quaternary sedimentary stack from underlying faulting. Overlaying and etched into this stratified unit are headscarp regions of two up to 450 m thick buried MTDs, characterized by distinct combinations of chaotic seismic reflections and typically ~1 km wide detached and rotated blocks. “Crowns” of growth faults emanate upward from these MTD headwalls, truncating and deforming the overburden and offsetting overlaying reflections by tens of meters up to ~100 m below the seafloor. Moreover, asymmetric sagging and faulting of the overburden mimic the layout and flow pattern of the MTDs and rafted blocks within, providing kinematic indications of combined compaction and lateral flow. These observations imply that the MTDs undergo continuous postslumping differential compaction, combined with lateral mobilization. Additional smaller and younger buried MTDs distributed within the overburden are observed to portray similar deformation kinematics. We suggest that the buried MTDs provide deformational foci and pathways for downslope internal collapse of the continental margin at large, offering a new possible mechanism of thin-skinned extension.
Bibliographical noteFunding Information:
This research was funded by student grants of the Moses Strauss Department of Marine Geosciences and AMEL internal funds, Charney School of Marine Sciences, University of Haifa. We thank Paradigm for their software sponsorship; The Petroleum Commissioner, Ministry of National Infrastructure, Energy and Water Resources, State of Israel, for permitting the academic usage of the data; Modiin Energy and the Bathymetric Survey of Israel for data sharing; Alexander Surdyaev for technical support; Amotz Agnon, Nicolas Waldmann, Emmanuel Eruteya, and Nimer Taha for their helpful comments; and Davide Gamboa, Mathieu Rodriguez, and J. Bruce H. Shyu for their valuable reviews. The seismic data used in this work are available, contingent on approval and payment procedures, from the Petroleum Commissioner, Ministry of National Infrastructure, Energy and Water Resources, State of Israel. Interpretation maps and attributes used to produce the figures of this paper can be made available, upon request, by the corresponding author.
©2017. American Geophysical Union. All Rights Reserved.
- continental margins
- mass transport deposits
- passive margin deformation
- sediments load
- thin-skinned extension
ASJC Scopus subject areas
- Geochemistry and Petrology