Sedimentology of Shale

Potter, Paul Edwin; Maynard, J. Barry; Pryor, Wayne A.

doi:10.1007/978-1-4612-9981-3

Cited by 281 publications

(163 citation statements)

References 59 publications

Supporting

Mentioning

146

Contrasting

Unclassified

Order By: Relevance

“…6). The relationship between organic carbon concentration and optical density shown in Figure 6 fits the well-established association between sediment color and organic carbon concentration in fine-grained sediments, which has been characterized as a trend in which modest organic carbon contents (<1%) impart a strong dark color, and increasing organic carbon concentration produces a consistent increase in color darkness, but with considerable spread (Potter et al, 1980). Patterns of color variation as a function of calcium carbonate and organic matter abundance in part are related in that a general inverse relationship between calcium carbonate and organic carbon concentrations exists in Owen Ridge and Oman margin sediments (Prell, Niitsuma, et al, 1989).…”

Section: Characteristics Of Bulk Density and Color Variationsupporting

confidence: 74%

“…The effect of this variation on changes in wet-bulk density is probably minor. Color variation of fine-grained sediments is primarily controlled by two factors: (1) oxidation state of iron, the Fe 3+ /Fe 2+ ratio, and (2) amount of organic carbon present (Potter et al, 1980). These two factors are partly related in that presence of small amounts of organic matter favors the reduced form of iron (Fe 2+ ).…”

Section: Discussionmentioning

confidence: 99%

“…These two factors are partly related in that presence of small amounts of organic matter favors the reduced form of iron (Fe 2+ ). Potter et al (1980) have divided color variation of fine-grained sediments into two series, a red to purple to greenish gray series based on Fe 3 + /Fe 2+ and a greenish gray to gray to black series based on organic carbon content. Sediments lacking iron compounds or organic matter as pigments display colors associated with other constituents.…”

Section: Discussionmentioning

confidence: 99%

“…Sediments lacking iron compounds or organic matter as pigments display colors associated with other constituents. These sediments are characterized by bluish colors, pale blue or pale blue green, where carbonate minerals are abundant (Potter et al 1980) and green colors where the true color of clay minerals shows through (Blatt, 1982).…”

Section: Discussionmentioning

confidence: 99%

See 3 more Smart Citations

Analysis of Wet-Bulk Density and Sediment Color Cycles in Pliocene-Pleistocene Sediments of the Owen Ridge (Site 722) and Oman Margin (Site 728)

Busch¹

1991

Proceedings of the Ocean Drilling Program

View full text Add to dashboard Cite

Pliocene and Pleistocene sediments of the Oman margin and Owen Ridge are characterized by continuous alternation of light and dark layers of nannofossil ooze and marly nannofossil ooze and cyclic variation of wet-bulk density. Origin of the wet-bulk density and color cycles was examined at Ocean Drilling Program Site 722 on the Owen Ridge and Site 728 on the Oman margin using 3.4-m.y.-long GRAPE (gamma ray attenuation) wet-bulk density records and records of sediment color represented as changes in gray level on black-and-white core photographs. At Sites 722 and 728 sediments display a weak correlation of decreasing wet-bulk density with increasing darkness of sediment color. Wet-bulk density is inversely related to organic carbon concentration and displays little relation to calcium carbonate concentration, which varies inversely with the abundance of terrigenous sediment components. Sediment color darkens with increasing terrigenous sediment abundance (decreasing carbonate content) and with increasing organic carbon concentration. Upper Pleistocene sediments at Site 722 display a regular pattern of dark colored intervals coinciding with glacial periods, whereas at Site 728 the pattern of color variation is more irregular. There is not a consistent relationship between the dark intervals and their relative wet-bulk density in the upper Pleistocene sections at Sites 722 and 728, suggesting that dominance of organic matter or terrigenous sediment as primary coloring agents varies. Spectra of wet-bulk density and optical density time series display concentration of variance at orbital periodicities of 100, 41, 23, and 19 k.y. A strong 41-k.y. periodicity characterizes wet-bulk density and optical density variation at both sites throughout most of the past 3.4 m.y. Cyclicity at the 41-k.y. periodicity is characterized by a lack of coherence between wet-bulk density and optical density suggesting that the bulk density and color cycles reflect the mixed influence of varying abundance of terrigenous sediments and organic matter. The 23-k.y. periodicity in wet-bulk density and sediment color cycles is generally characterized by significant coherence between wet-bulk density and optical density, which reflects an inverse relationship between these parameters. Varying organic matter abundance, associated with changes in productivity or preservation, is inferred to more strongly influence changes in wet-bulk density and sediment color at this periodicity.

show abstract

Section: Characteristics Of Bulk Density and Color Variationsupporting

confidence: 74%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Analysis of Wet-Bulk Density and Sediment Color Cycles in Pliocene-Pleistocene Sediments of the Owen Ridge (Site 722) and Oman Margin (Site 728)

Busch¹

1991

Proceedings of the Ocean Drilling Program

View full text Add to dashboard Cite

show abstract

“…The C org content tends to be higher in dark layers, suggesting that the presence of organic carbon contributes to the dark color (Potter et al, 1980;Tada, 1991). This tendency is clearly illustrated when the gray value of the sediments is plotted against their C org content (Fig.…”

Section: Carbon and Sulfur Contentsmentioning

confidence: 99%

Correlation of Dark and Light Layers, and the Origin of Their Cyclicity in the Quaternary Sediments from the Japan Sea

Tada¹,

Koizumi²,

Cramp³

et al. 1992

Proceedings of the Ocean Drilling Program

View full text Add to dashboard Cite

Nearly continuous cores of Quaternary fine-grained sediments with distinct dark-light colored cycles were recovered from Sites 794, 795, and 797 in the basinal parts of the Japan Sea during Leg 127. A comparison of gray value (darkness) profiles supplemented by visual inspection of core photographs between sites indicated that most of the dark and light layers were correlatable between sites, and that two of the dark layers lie close to adjacent marker ash layers. These observations indicate that deposition of dark and light layers resulted from basin-wide synchronous events.In order to understand the origin of these dark-light cycles, petrographical, mineralogical, compositional, and paleontological studies were carried out on closely spaced samples from the upper Quaternary sediments recovered from Site 797. Age model was constructed based on comparison between variation in diatom abundance and the standard oxygen isotope curve of Imbrie et al. (1984), the latter was interpolated between the five age controlled levels established at Site 797. The two curves show similar patterns which enabled us to "tune" the sediment ages to the oxygen isotope stages. We have to use variation in diatom abundance as a substitute for oxygen isotope curve since oxygen isotopic data are not available at the studied sites.Bottom water oxygenation conditions were estimated based on two criteria: (1) the degree of lamina preservation and (2) the ratio of C org to S tot . The surface water productivity was deduced from the C org and biogenic silica content.Results suggest that the bottom water oxygenation level and the surface water productivity varied significantly in response to the glacial-interglacial cycles. Glacio-eustatic sea-level changes and subsequent changes in water circulation in the Japan Sea appear to have been responsible for these variations and consequent changes in sediment composition throughout the Quaternary.

show abstract

Reconstruction of rocks petrophysical properties as input data for reservoir modeling

Cantucci

Montegrossi

Lucci

et al. 2016

Geochem Geophys Geosyst

View full text Add to dashboard Cite

The worldwide increasing energy demand triggered studies focused on defining the underground energy potential even in areas previously discharged or neglected. Nowadays, geological gas storage (CO2 and/or CH4) and geothermal energy are considered strategic for low‐carbon energy development. A widespread and safe application of these technologies needs an accurate characterization of the underground, in terms of geology, hydrogeology, geochemistry, and geomechanics. However, during prefeasibility study‐stage, the limited number of available direct measurements of reservoirs, and the high costs of reopening closed deep wells must be taken into account. The aim of this work is to overcome these limits, proposing a new methodology to reconstruct vertical profiles, from surface to reservoir base, of: (i) thermal capacity, (ii) thermal conductivity, (iii) porosity, and (iv) permeability, through integration of well‐log information, petrographic observations on inland outcropping samples, and flow and heat transport modeling. As case study to test our procedure we selected a deep structure, located in the medium Tyrrhenian Sea (Italy). Obtained results are consistent with measured data, confirming the validity of the proposed model. Notwithstanding intrinsic limitations due to manual calibration of the model with measured data, this methodology represents an useful tool for reservoir and geochemical modelers that need to define petrophysical input data for underground modeling before the well reopening.

show abstract

Sedimentology of Shale

Cited by 281 publications

References 59 publications

Analysis of Wet-Bulk Density and Sediment Color Cycles in Pliocene-Pleistocene Sediments of the Owen Ridge (Site 722) and Oman Margin (Site 728)

Analysis of Wet-Bulk Density and Sediment Color Cycles in Pliocene-Pleistocene Sediments of the Owen Ridge (Site 722) and Oman Margin (Site 728)

Correlation of Dark and Light Layers, and the Origin of Their Cyclicity in the Quaternary Sediments from the Japan Sea

Reconstruction of rocks petrophysical properties as input data for reservoir modeling

Contact Info

Product

Resources

About