Organic matter and the geotechnical properties of submarine sediments

Keller, George H.

doi:10.1007/bf02462762

Cited by 59 publications

(45 citation statements)

References 19 publications

(14 reference statements)

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“…Judging from grain size (very fine sandstone) and abundant relict stratification, almost all of these beds with soft-sediment deformation were originally dominated by climbing-ripple stratification. The susceptibility of fine cohesionless sediment (silt to very fine sand) to liquefaction is well established (Terzaghi and Peck 1948;Keller 1982). These convolute beds contain well-developed folds with consistent asymmetries (Figs.…”

Section: Thin-to Medium-bedded Sandstone and Shale Faciesmentioning

confidence: 91%

Wave-Modified Turbidites: Combined-Flow Shoreline and Shelf Deposits, Cambrian, Antarctica

Myrow¹,

Fischer²,

Goodge³

2002

Journal of Sedimentary Research

173

118

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Sandstone tempestite beds in the Starshot Formation, central Transantarctic Mountains, were deposited in a range of shoreline to shelf environments. Detailed sedimentological analysis indicates that these beds were largely deposited by wave-modified turbidity currents. These currents are types of combined flows in which storm-generated waves overprint flows driven by excess-weight forces. The interpretation of the tempestites of the Starshot Formation as wave-dominated turbidites rests on multiple criteria. First, the beds are generally well graded and contain Bouma-like sequences. Like many turbidites, the soles display abundant well-developed flutes. They also contain thick divisions of climbing-ripple lamination. The lamination, however, is dominated by convex-up and sigmoidal foresets, which are geometries identical to those produced experimentally in current-dominated combined flows in clear water. Finally, paleocurrent data support a turbidity-current component of flow. Asymmetric folds in abundant convolute bedding reflect liquefaction and gravity-driven movement and hence their orientations indicate the downslope direction at the time of deposition. The vergence direction of these folds parallels paleocurrent readings of flute marks, combined-flow ripples, and a number of other current-generated features in the Starshot event beds, indicating that the flows were driven down slope by gravity. The wave component of flow in these beds is indicated by the presence of small-to largescale hummocky cross-stratification and rare small two-dimensional ripples.Wave-modified turbidity currents differ from deep-sea turbidity currents in that they may not be autosuspending and some proportion of the turbulence that maintains these flows comes from storm waves. Such currents are formed in modern shoreline environments by a combination of storm waves and downwelling sediment-laden currents. They may also be formed as a result of oceanic floods, events in which intense sediment-laden fluvial discharge creates a hyperpycnal flow. Event beds in the Starshot Formation may have formed from such a mechanism. Oceanic floods are formed in rivers of small to medium size in areas of high relief, commonly on active margins. The Starshot Formation and the coeval Douglas Conglomerate are clastic units that formed in response to uplift associated with active tectonism. Sedimentological and stratigraphic data suggest that coarse alluvial fans formed directly adjacent to a marine basin. The geomorphic conditions were therefore likely conducive to rapid fluvial discharge events associated with storms. The abundance of current-dominated combinedflow ripples at the tops of many Starshot beds indicates that excessweight forces were dominant throughout deposition of many of these beds.

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Section: Thin-to Medium-bedded Sandstone and Shale Faciesmentioning

confidence: 91%

Wave-Modified Turbidites: Combined-Flow Shoreline and Shelf Deposits, Cambrian, Antarctica

Myrow¹,

Fischer²,

Goodge³

2002

Journal of Sedimentary Research

173

118

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“…The sediments present some affinities with eastern Mediterranean deposits (low densities and shear strength), but are quite typical of central Mediterranean deposits: lower water content, relatively high plasticity characteristics (Figure 3a-3b), intermediate between those of western and eastern Mediterranean sediments (Keller and Lambert, 1972); the last phenomena are due to the particularly high content of smectite that issued from the Mio- Table 1, demonstrate the various correlations; the different zones appear to be well distinguished. Plotting along the A-line from clay of low plasticity to clays of high plasticity is principally a function of:…”

Section: Geotechnical Properties Of Trenches and Deepest Parts Of Marmentioning

confidence: 94%

“…Examples of grain size influence: sediments from the Pelagian Sea, which are often the coarsest, frequently show: With reference to this, the increase of the Atterberg limits of continental margin deposits of the Adriatic Sea may reflect their influence on part of the geotechnical properties of the central Mediterranean abyssal deposits (Keller and Lambert, 1972).…”

Section: Geotechnical Properties and Sedimentary Fades Of Continentalmentioning

confidence: 99%

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On the use of Atterberg limits on marine soils

Chassefiere

Monaco

1983

Marine Geotechnology

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On the basis of the Atterberg indexes of various sediments collected in the Mediterranean Sea, we select two major parameters indicative of the mechanical behavior of marine soils: the sedimentary facies (i.e., mechanism of deposition expressed by silt content) and the clay mineral association characterized by smectite content in the fraction finer than 2 µm. Activity and real thixotropic ability appear to be particularly important parameters in marine engineering; better values are obtained by a double test operation in distilled and marine water.

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“…Again, an increase in liquid and plastic limits with increasing organic content was found. Keller (1982) suggests that several index properties of marine sediments, including plasticity, correlate well with organic carbon at levels near 2%, but that strength characteristics may not be influenced until organic carbon contents reach 4-5%.…”

Section: Introductionmentioning

confidence: 95%

A note on the relationships between organic matter and some geotechnical properties of a marine sediment

Booth

Dahl

1986

Marine Geotechnology

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An analysis of the relationship between organic matter and liquid and plastic limits, and grain-specific gravity of a marine sediment was accomplished by making a stepwise adjustment in the organic content of that sediment. The sample used was from Santa Barbara Basin (off southern California) and is typical of fine-grained marine sediments: it is a clayey silt with a common suite of minerals and other constituents. During the experiment, texture and composition (except organic content) were constant; only the quantity of natural, indigenous organic matter was changed.A strong linear relationship exists between the independent variable, the amount of organic carbon present in the sample, and the dependent variables. Liquid limit, plastic limit, and plasticity index all increased with increasing organic content over the range studied (0.57-3.20% organic carbon). Grain-specific gravity decreased. All had linear correlation coefficients (r) greater than |0.90| and r 2 values greater than 90%, except the plasticity index (83%).Comparing the results of regression analyses from this and several similar studies shows that although there is good qualitative agreement, there are quantitative inconsistencies. In particular there is considerable overall variability in the regression coefficients. Among studies on marine sediments the inconsistencies are less pronounced, yet still evident. The increase in liquid limit as organic carbon increased by 1 % sediment dry weight ranged from 9 to 28% water content; in the plastic limit the range was from 4 to 18%. However, in these marine studies regression coefficients are relatively close in value in some cases, levels of significance of the regressions are high in most cases, and in all cases the relationships appear to be linear over the range of organic carbon percentage studied. Finally, we believe that a relatively clear relationship between plasticity and organic carbon begins to emerge when the latter exceeds a value of 2%.

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Organic matter and the geotechnical properties of submarine sediments

Cited by 59 publications

References 19 publications

Wave-Modified Turbidites: Combined-Flow Shoreline and Shelf Deposits, Cambrian, Antarctica

Wave-Modified Turbidites: Combined-Flow Shoreline and Shelf Deposits, Cambrian, Antarctica

On the use of Atterberg limits on marine soils

A note on the relationships between organic matter and some geotechnical properties of a marine sediment

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