Sizes of submarine slides and their significance

“…Detachment of sediment from the upper slope is a possible source for the Pleistocene slumps. Such localized slope detachments are a common type of failure observed in the Quaternary sediments seaward of New Jersey and Delaware (McGregor and Bennett, 1977, 1979Malahoff et al, 1980;Farre and Ryan, 1987). Similar localized upper slope failures and detachments were also probably the source for the Miocene debris flows of Facies 1.…”

Section: Discussionmentioning

confidence: 93%

“…Various classifications of these processes and their resulting deposits have been proposed and in this paper, we follow the terminology originally proposed by Varnes (1958), Dingle (1977) and Embley and Jacobi (1977) with slight modification by Shanmugam et al (1994Shanmugam et al ( , 1995. Slumps and slides are sometimes not distinguished from each other in the literature (Woodcock, 1979) because both processes involve downslope movement of sediment as a coherent mass. However, in this paper we differentiate the two processes as follows.…”

Section: Deep-marine Gravity-controlled Sedimentary Processesmentioning

confidence: 99%

“…Slump facies were identified in Leg 150 cores using the following criteria: (1) soft-sediment folds, (2) contorted or discordant bedding, (3) steeply dipping layers (up to 60°) with various orientations, (4) basal (primary) glide planes and shear zones, (5) internal (secondary) glide planes, (6) abrupt changes in lithology or fabric, (7) inclined dish structures, (8) brecciated zones, and (9) clastic injections (Helwig, 1970;Woodcock, 1976;Jacobi, 1976;Gawthorpe and Clemmey, 1985;Martinsen, 1989;Shanmugam et al, 1994Shanmugam et al, , 1995.…”

Section: Deep-marine Gravity-controlled Sedimentary Processesmentioning

confidence: 99%

See 1 more Smart Citation

Oligocene to Holocene Mass-Transport Deposits of the New Jersey Continental Margin and Their Correlation to Sequence Boundaries

McHugh¹,

Damuth²,

Gartner³

et al. 1996

Proceedings of the Ocean Drilling Program, 150 Scientific Results

View full text Add to dashboard Cite

The styles of soft-sediment deformation, mineralogy, and biostratigraphy of mass-transport deposits recovered from Leg 150 drill sites (902-906) provide important new information on the erosional and sedimentary history of the New Jersey continental slope and rise, and on the relationship of mass-wasting processes to changes in relative sea level. Nine distinct sedimentary facies are recognized within these mass-transport deposits, which mainly represent muddy slumps and debris flows, and to a lesser extent, sandy mass flows. These sedimentary facies, coupled with the ages of their clast and matrix material, reveal source areas, transport mechanisms, and depositional processes, and the relative contribution of downslope transport to the evolution of the continental rise.Mass-wasting deposits compose 10%-15% of the total sediment recovered beneath the continental slope at Sites 902, 903, and 904. Upper Miocene and Pleistocene debris flows and slumps frequently correlate to sequence boundaries beneath the upper paleoslope at Site 903, and to a lesser extent, beneath the middle paleoslope at Sites 902 and 904. In contrast, upper Oligocene to upper Miocene sands and sandy mass flows correlate to sequence boundaries beneath the middle paleoslope at Sites 902 and 904 and not beneath the upper paleoslope at Site 903. Mass flows at these sites document shelf and coastal plain erosion and sediment transport to the basin during glacioeustatic lowering. These observations suggest a correlation between mass-transport deposits and sequence boundaries. However, this correlation is complex because preservation of mass-wasting deposits appears to have been significantly influenced by the morphology and gradient of the existing paleoslope. In addition, mass-transport deposits also occur within sequences especially during the upper Miocene and Pleistocene.Site 906 was drilled in the floor of modern Berkeley submarine canyon. The sedimentary facies recovered from the middle Miocene section document an episode of canyon excavation and infilling. The Berkeley and middle Miocene canyon fill facies are different from the mass-transport deposits that characterize intercanyon regions of the slope (they contain debris flows with clasts of diverse ages and multiple turbidites). The middle Miocene canyon cutting event apparently occurred very rapidly (~l.l m.y.) during a single third-order sea-level cycle (13.5-12.4 Ma) and the mass-transport deposits at the base of the canyon fill rest upon a Type I sequence boundary, which forms the canyon floor.Downslope transport of sediment via mass movements has episodically contributed to the evolution of the upper continental rise. At Site 905 on the continental rise, approximately 30 m of mass-transport deposits were accumulated during the middle Miocene. Benthic foraminifer assemblages indicate that some deposits originated in the upper slope. The lithology of the clasts in these deposits indicates they were derived from canyon excavation on the continental slope and the age of the matrix...

show abstract

“…The earthquake hypothesis could possibly be used to explain some of these difficulties. It is reasonable to suppose that short-lived episodes of seismicity have occurred, a part of the ongoing geological evolution of the Atlantic margin and that "swarms" of earthquakes have led to recurrent slope failure in localized areas (Woodcock, 1979) walls. It is even plausible to assert that some of the intrastratal deformation could be a consequence of ground shaking.…”

Section: Comparative Features Of the Landslide Complexesmentioning

confidence: 99%