Efficiencies of Percentile Measures for Describing the Mean Size and Sorting of Sedimentary Particles

McCammon, Richard B.

doi:10.1086/626836

Cited by 65 publications

(26 citation statements)

References 8 publications

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“…Many formulae have been proposed (e.g. Trask, 1932;Krumbein, 1938;Otto, 1939;Inman, 1952;McCammon, 1962) although the most widely used are those proposed by Folk and Ward (1957). Such techniques are most appropriate for the analysis of open-ended distributions, since the tails of the distribution, which may include extreme outliers, are ignored.…”

Section: Fundamentals Of Grain Size Analysismentioning

confidence: 99%

GRADISTAT: a grain size distribution and statistics package for the analysis of unconsolidated sediments

Blott¹,

Pye²

2001

Earth Surf Processes Landf

3,435

1,668

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Grain size analysis is an essential tool for classifying sedimentary environments. The calculation of statistics for many samples can, however, be a laborious process. A computer program called GRADISTAT has been written for the rapid analysis of grain size statistics from any of the standard measuring techniques, such as sieving and laser granulometry. Mean, mode, sorting, skewness and other statistics are calculated arithmetically and geometrically (in metric units) and logarithmically (in phi units) using moment and Folk and Ward graphical methods. Method comparison has allowed Folk and Ward descriptive terms to be assigned to moments statistics. Results indicate that Folk and Ward measures, expressed in metric units, appear to provide the most robust basis for routine comparisons of compositionally variable sediments. The program runs within the Microsoft Excel spreadsheet package and is extremely versatile, accepting standard and non-standard size data, and producing a range of graphical outputs including frequency and ternary plots.

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Section: Fundamentals Of Grain Size Analysismentioning

confidence: 99%

GRADISTAT: a grain size distribution and statistics package for the analysis of unconsolidated sediments

Blott¹,

Pye²

2001

Earth Surf Processes Landf

3,435

1,668

View full text Add to dashboard Cite

show abstract

“…Sediment analyses were performed from a 100-g sediment subsample (dried for 24 h at 60°C) (Buchanan 1984), and granulometric parameters were obtained with the RYS-GRAN package for R (R Development Core Team 2012), following the method of McCammon (1962). Verbal classification is based on Wentworth tables (Wentworth 1922).…”

Section: Sediment Analysesmentioning

confidence: 99%

Protodrilus (Protodrilidae, Annelida) from the southern and southeastern Brazilian coasts

et al. 2013

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Protodrilus corderoi, Protodrilus ovarium n. sp. and Protodrilus pythonius n. sp. are reported from beaches in southern and southeastern Brazil and described combining live observations with light and electron scanning microscopy studies. Protodrilus corderoi is redescribed from new collections at the type locality, and a neotype for the species is assigned since the original type material no longer exists. New information on reproductive organs, segmental adhesive glands and unpigmented ciliary receptors as well as morphometrics is provided. Protodrilus ovarium n. sp. and P. pythonius n. sp. are formally described. Protodrilus ovarium n. sp. is diagnosed by the presence of separated lateral organs on segments 7-12, three spermioducts of segments 10-12 and salivary glands in segments 1-9. Protodrilus pythonius n. sp. is defined by the presence of separated lateral organs on segments 7-16, long pygidial lobes and body tapering toward the pygidium. The distribution of the different species in more or less spacious habitats seems to be correlated with their gross morphology. Protodrilus pythonius n. sp., with relatively long and wide body and long palps with ciliary bands, was collected in very coarse sandy sediments at a reflective sheltered beach. Conversely, P. corderoi and P. ovarium n. sp., both possessing more slender bodies with shorter, less ciliated palps, occurred in medium-coarse, well-sorted sediments in the more energetic swash zone of exposed intermediate-reflective beaches. The finding of P. pythonius and P. corderoi in nearby beaches corroborates other studies showing a higher morphological variability among species in different habitats within the same geographical area than among species in the same habitat in different geographical areas.

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“…The grain-size is expressed in phi-scale (negative log 2 of grain-size measured in millimeter). There are different quantitative definition of sorting in the sedimentology literature (eg., Inman, 1957, Folk and Ward, 1957and McCammon, 1962. We use Folk and Ward (1957) method to compute sorting coefficient as described below.…”

Section: Grain Size and Sorting Variationsmentioning

confidence: 99%

Imaging Reservoir Quality: Seismic Signatures of Geologic Processes

Mavko¹

2008

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Lithofacies successions from diverse depositional environments show distinctive patterns in various rock-physics planes (velocity-porosity, velocity-density and porosityclay). Four clear examples of decameter-scale lithofacies sequences are documented in this study: (1) Micocene fluvial deposits show an inverted-V pattern indicative of dispersed fabric, (2) a fining-upward sequence of mud-rich deep deposits shows a linear trend associated with laminated sand-clay mixtures, (3) sand-rich deposits show a pattern resulting from the scarcity of mixed lithofacies, and (4) a coarsening-upward sequence shows evidence of both dispersed and horizontally laminated mixed lithofacies, with predominating dispersed mixtures generated by bioturbation..It was observed that carbonate-cemented sandstones are extremely heterogeneous in the project deep-water study area. Those from the base of incisions are usually associated with lower shaliness, lower porosity and higher P-impedance, while from the top of flooding surfaces exhibit higher shaliness, higher porosity and lower P-impedance. One rock physics model that captures the observed impedance-porosity trend is the "stiff-sand model." For this model, the high-porosity end-member is unconsolidated sand whose initial porosity is a function of sorting and shaliness, while the low-porosity end-member is solid mineral. These two end points are joined with a Hashin-Shtrikman equation.A systematic variation of quartz:clay ratio from proximal to distal locations was observed in the study area even within a single facies. The quartz:clay ratio changes from [0.5:0.5] to [1:0] along the direction of flow, based on the trends of P-impedance vs. porosity as predicted by the rock model for uncemented sands. The results are in agreement with spill-and-fill sequence stratigraphic model in mini-basin setting. In addition, porosity at the distal location (~25 % to 35%) is higher than the porosity at the proximal location (~20 % to 23%). This trend is explained by a sequence stratigraphic model which predicts progressive increase in sorting by turbidity current along the flow, as well as, quantified by a rock model that heuristically accounts for sorting. The results can be applied to improve quantitative predication of sediment parameters from seismic impedance, away from well locations. Figure 1. Conceptual model illustrating the concomitant changes in porosity and elastic properties of clastic sediments. These textural effects have been documented by previous studies: e.g. , , , , , , , . Figure 2. Rock-physics template to evaluate the patterns of concomitant variations of porosity and elastic properties within clastic sequences. Porosity determined from density and neutron (in sands) logs, clay fraction determined from gamma ray and the difference between neutron and density porosities. Figure 6. Bivariate histograms of well-log P-wave velocity and porosity (PHID) from the four different clastic depositional sequences shown in Figure A-10. Q indicates the sand points (quartzose sand...

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Efficiencies of Percentile Measures for Describing the Mean Size and Sorting of Sedimentary Particles

Cited by 65 publications

References 8 publications

GRADISTAT: a grain size distribution and statistics package for the analysis of unconsolidated sediments

GRADISTAT: a grain size distribution and statistics package for the analysis of unconsolidated sediments

Protodrilus (Protodrilidae, Annelida) from the southern and southeastern Brazilian coasts

Imaging Reservoir Quality: Seismic Signatures of Geologic Processes

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