Poorly sorted

Poorly sorted sediments comprise very different particle sizes, resulting in a dense rock fabric wifh low porosify. As a resulf the connate water saturation is high, leaving little space for the storage of hydrocarbons. Conversely, a very well sorted sediment will have a large volume of space between the evenly sized components, a lower connate water saturation and hence a larger capacity to store hydrocarbons. Connate water is the water which remains in the pore space after the entry of hydrocarbons. 

Silty, fine grained sandstone, poorly sorted... 

Relatively moderate permeability, poorly sorted silty sand. 

Ice rafting is responsible for 7% of the terrigenous input of siliclastic particles to the ocean. When the ice melts, the particles settle to the seafloor to form glacial marine deposits. These are currently forming at latitudes greater than 40°N and 50° S. Most of the glacial marine sediments are poorly sorted deposits composed of relatively unweathered materials with chlorite being the dominant clay mineral. In the North Atlantic, layers... 

Unsorted sediments Sediments that contain unconsolidated grains exhibiting a wide range of particle sizes. Same as poorly sorted sediments. 

The glacial till deposits consist of poorly sorted to unsorted, nonstratified till ranging from muddy gravel to sandy coarse gravel. Pebbles and small cobbles are dominant. Surface morphology commonly includes morainal ridges, dry and water-filled kettle depressions, and meltwater channels (Hamilton 2007). 

Between 80 Ma and 50 Ma, the Namib rocks were eroded to a smooth peneplain (the Namib Unconformity). Namib Group Tertiary and Quaternary sedimentary debris was deposited in east-west to southwest trending paleochannels incised into Karibib marbles and schists on that Cretaceous age unconformity. From mid Tertiary to present, the central Namib region has maintained profoundly arid climatic conditions for the last 50 or more million years. Uplift initiated the post African erosion surface that filled valleys and channels with poorly sorted angular... 

Till A poorly sorted sediment deposited by glaciers. 

SORTING POOR SORTING GOOD R0UN0E0 AABRADED... 

The term sorting describes the relative amounts of different grain sizes in a rock. A well-sorted sandstone will contain only sand-sized grains, while a poorly sorted sandstone will include a large percentage of silt, clay or larger grains. 

There are a few other terms commonly used to describe sandstones. A wacke is a poorly sorted sandstone containing more than 10% argillaceous material (clay). Arenites are well-sorted sandstones having little or no clay in them. An arkose is a sandstone whose particles are derived from plutonic rocks and so consist largely of quartz and feldspar. 

Fine-grained deposits are indicative of either low energy or a long distance from the source rock. In some cases these deposits may represent fine-grained material winnowed from older, poorly-sorted deposits. Rounded, sand to cobble-sized deposits are indicative of relatively high energy stream deposition. 

The rocks in which the conglomerates lie are also similar yellow-green to grey elastics, some clean and well washed as at Elliot Lake and some being poorly sorted and dirty. They are, with one exception, only very slightly metamorphosed, they lie with profound unconformity on highly metamorphosed strata and they underlie a red rock sequence which contains no pyrite. 

The Arcturus Formation is structurally over-lain by felsic volcanic rocks and volcaniclastic sedimentary rocks (Passaford and Lower Shamva formations) and intercalated graphitic argillites (Mount Hampden Formation). Tuffaceous rocks and volcanic breccias occur in close association with porphyry stocks. All are andesitic to dacitic in composition. Associated epiclastic sedimentary rocks are poorly sorted massive, structureless and planar-bedded deposits. Clasts are felsic in composition and include crystal tuff, porphyry and chert, suggesting a very localized provenance. This felsic volcanism has been dated at 2643 8 Ma (Figs 2a and 3g, Wilson et al. 1995) and is associated with the emplacement of late-tectonic... 

FIGURE 3-3 Particle size, size distribution, and hydraulic conductivity in soil. In a well-sorted soil, all the particles are similar in size, giving the soil a relatively high hydraulic conductivity compared with an otherwise similar but poorly sorted soil, in which small soil particles block the pore spaces between larger particles, thereby decreasing the hydraulic conductivity. 

A generalized stratigraphic column of the area (Dalland et al., 1988) is shown in Fig. 3. The poorly sorted, shallow marine sandstones of the Tilje Formation, is overlain by the Ror Formation, which consists predominantly of clay- and silt-stones, in an overall coarsening upward trend. The Ror Formation is overlain by a regressive sandstone known as the... 

Well-sorted sands -3 to -5 Poorly-sorted sand gravel 25 to 40... 

CS Crevasse splay deposits Trough cross-bedded sand (St) planar laminated sand (Sp) low angle cross-bedded sand (SI) horizontally laminated sand (Sh) ripple cross-laminated sand (Sr) massive sand (Sm) Tabular, massive, lenticular, to thin wedge-shaped sands, 0.2-4 m thick 0.5 m to 0.5 km in lateral extent Poorly sorted sands and silty sands Thin sandstone sheets are usually well cemented... 

ES Aeolian sandsheet deposits Low angle cross-bedded sand (Sle) horizontally laminated sand (She) ripple cross-laminated sand (Sre) Tabular 1-2 m thick >1 km lateral extent Fine to medium moderately to poorly sorted sand/sandstone Coarser layers often form well cemented type 1 and type 3 (phreatic)... 

Fig. 12A). The most common, thickest and most laterally extensive units (>2 km) are those that are close in appearance to type 1 tabular units (Fig. 7). Mixed feature cements near the type 2 end-member are associated with more poorly sorted, finer grained layers and pit, tube and rod structures, with some evidence of the original sedimentary structures (type 3) (Fig. 12B). 

In the Upper Namur Sandstone the poikilotopic calcite cement is absent in moderately to poorly sorted quartz arenites and feldspathic quartz aren-ites that contain abundant primary porosity and some secondary porosity. Only minor patches of siderite micrite and microspar are observed in these elastics, where euhedral quartz overgrowths are well developed, albeit not volumetrically significant (< 5-10%) (Fig. 14D). The detrital grains are dominated by tangential and long contacts, with rare sutured contacts. 

Fig. 9. BSE image of a fine-grained, moderate to poorly sorted back-barrier marsh sample completely cemented by SI (white). Note the serrated nature of some quartz grains and the very high intergranular volume (>50%), which suggest the replacement of part of the margins of quartz grains by siderite cement. Sample F4-9441, Fly Lake 4, 2877.6 m. Scale bar = 500 pm.

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