Meso-Scale Kinematic Indicators in Exhumed Mass Transport Deposits: Definitions and Implications

Abstract

In this study we combine observations and analytical data from large-scale (10-100s of m-thick and 100 m(2)-extensive), siliciclastic and carbonate MTD/MTCs belonging to the Oligocene - Miocene foredeep and wedge-top successions of the Northern Apennines and the Paleocene - Eocene Friuli basin of the northwestern Dinarides (Italy and Slovenia), to discuss the deformation processes critical to the emplacement of submarine landslides. We focus on the identification of meso-scale structures, used as diagnostic kinematic indicators of local paleo-transport directions. These structures, represented by linear-planar and complex-shaped elements such as tabular shear zones and detached slump-type folds, are the product of ductile-plastic deformation developed at relatively low-confining pressure that involves water-saturated, un- to poorly-lithified sediments, along with liquefaction/fluidization processes. Their final appearance is thus mainly controlled by the mechanical-rheological behavior of deformed sediments, and eventually by tectonic fabrics inherited from deeper structural levels of deformation. Due to this parallelism these structures have been termed and classified accordingly. They reflect strain partitioning due to differential movements within the slide mass, which is in turn controlled by the overall landslide typology. Due to the parallelism with classified tectonic structures and structural associations, we have thus redefined and classified accordingly meso-scale kinematic indicators in ancient MTD/MTCs

Characterization of the Rapanui mass‐transport deposit and the basal shear zone: Mount Messenger Formation, Taranaki Basin, New Zealand

“…Similar structures were named by Ogata et al . () as cuspidate injections and form during sudden dilation of the brittle beds (sandstone) resulting in forceful injection of the bounding plastic mudstones (Winterer et al., ). Boudins in the RMTD are shear‐band boudins ( sensu Goscombe et al., ).…”

“…). Common structures in the bsz are small‐scale folds (Clare et al., ; Ogata et al., ; Jablonská et al., ), ‘necking’ or boudinage (Tripsanas et al., ; Ogata et al., ), brecciation/cataclasis (Ineson, ; Farrell & Eaton, ; Callot et al., ), convolute/contorted bedding (Tripsanas et al., ; Butler et al., ) and structures associated with liquidization ( sensu Allen, 1982a). Furthermore, the bsz can be a zone of erosion if the mass flow erodes into the substratum or a bypass zone if there is little or no interaction between the mass flow and the substratum (Sobiesiak et al., ).…”

“…Each morphodomain is typically characterized by a locally dominant stress regime and the material in these morphodomains has stress‐reflective kinematic indicators (Farrell, ; Farrell & Eaton, ; Bull et al., ; Ogata et al., ). Some examples of such a kinematic indicators are grooves and folds.…”

Styles of basal interaction beneath mass transport deposits

“…All types of erosional features described above can be used as kinematic indicators for the movement of MTDs, as the linear axis of scours, grooves and/or peel-backs are usually parallel or elongated towards the main flow direction (e.g. Ogata et al, 2016;. The differentiation of MTD erosional features from turbidite erosion can be inferred on the basis of their occurrence upslope and/or beneath blocky debris flows (e.g.…”

Submarine Mass Movements and Their Consequences: Progress and Challenges

“…Outcrop investigations provide detailed insight into the kinematics (Ogata et al 2016) and internal mixing and structure (Sobiesiak et al 2016) of MTD. Sympathetic to these approaches are fine-scale sedimentological studies that provide a modern context of present day seafloor processes (Postma et al 2016;Sawyer and Hodelka 2016).…”