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| Valley fills within alluvial and marine strata || 2-210 m (6-689 ft); most < 60 m (197 ft) || 0.1-105 km (0.06-65 mi); common range 0.2-25 km (0.1-15 mi) || 4.6-3640; highly variable; common range 10-1000; many from 100 to 1000
| Valley fills within alluvial and marine strata || 2-210 m (6-689 ft); most < 60 m (197 ft) || 0.1-105 km (0.06-65 mi); common range 0.2-25 km (0.1-15 mi) || 4.6-3640; highly variable; common range 10-1000; many from 100 to 1000
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| colspan="4" | <sup>1</sup>''From Gibling<ref name=Gibling_2006 />, Journal of Sedimentary Research. Reprinted with permission from, and © by, the SEPM (Society for Sedimentary Geologists).''
| colspan="4" | <sup>1</sup>''From Gibling,<ref name=Gibling_2006 /> Journal of Sedimentary Research. Reprinted with permission from, and © by, the SEPM (Society for Sedimentary Geologists).''
|}
|}
Sand is deposited within linear distributary channels as side bars. In the modern-day Mahakam Delta, Borneo, side bars alternate on both sides of the distributary channels. These form elliptical sand pods, 5–8 km (3–5 mi) or more long and up to 1 km (0.6 mi) wide.<ref name=Allenandchambers_1998>Allen, G. P., and J. L. C. Chambers, 1998, Sedimentation in the modern and Miocene Mahakam delta: Indonesian Petroleum Association, 236 p.</ref> Channel fills typically show an upward-fining sediment profile and an upward-decreasing permeability profile. From the base upward, a distributary channel comprises the active channel fill, showing decimeter-scale trough cross-bedded sets; a partial abandonment fill with mainly centimeter-scale cross-beds; and sometimes an abandonment channel fill of thinly interbedded fine sand, silt, and shale.
Sand is deposited within linear distributary channels as side bars. In the modern-day Mahakam Delta, Borneo, side bars alternate on both sides of the distributary channels. These form elliptical sand pods, 5–8 km (3–5 mi) or more long and up to 1 km (0.6 mi) wide.<ref name=Allenandchambers_1998>Allen, G. P., and J. L. C. Chambers, 1998, Sedimentation in the modern and Miocene Mahakam delta: Indonesian Petroleum Association, 236 p.</ref> Channel fills typically show an upward-fining sediment profile and an upward-decreasing permeability profile. From the base upward, a distributary channel comprises the active channel fill, showing decimeter-scale trough cross-bedded sets; a partial abandonment fill with mainly centimeter-scale cross-beds; and sometimes an abandonment channel fill of thinly interbedded fine sand, silt, and shale.
[[file:M91FG123.png|thumb|300px|{{figure number|4}}A schematic delta showing a range of sand body types at their average dimensions, together with several oil and gas fields at the same scale. The delta front is divided into three segments that are storm-, fluvial-, and tidal-dominated, respectively. The delta and its divisions are not to scale (from Reynolds<ref name=Reynolds_1999>Reynolds, A. D., 1999, [http://archives.datapages.com/data/bulletns/1999/02feb/0211/0211.htm Dimensions of paralic sandstone bodies]: AAPG Bulletin, v. 83, no. 2, p. 211–229.</ref>).]]
[[file:M91FG186.JPG|thumb|300px|{{figure number|5}}Fluvial-dominated delta environment, Mississippi Delta. Photograph courtesy of the [http://www.earthasart.gsfc.nasa.gov NASA Web site]. The inset box on the photograph measures 34 times 42 km (21 times 26 mi). The lower diagram is a box diagram showing the sedimentological relationships within the inset box (after Fisk<ref name=Fisk_1961>Fisk, H. N., 1961, [http://archives.datapages.com/data/specpubs/sandsto1/data/a055/a055/0001/0000/0029.htm Bar-finger sands of the Mississippi delta], in J. A. Peterson and J. C. Osmond, eds., Geometry of sandstone bodies: AAPG Symposium, SP22, p. 29–52.</ref>).]]
==Mouth bars==
Mouth bars form where a distributary channel enters a standing body of water and sediment drops out. A shoaling to emergent sand body grows at the channel mouth. The resulting obstruction can cause the channel to bifurcate at the upstream head of the mouth bar. Mouth bars show an arcuate fan shape in plan view and a wedge-shaped profile in cross section. Reynolds<ref name=Reynolds_1999 /> gave average dimensions for mouth bars of about 3 km (1.8 mi) wide and about 6.5 km (4 mi) long (see [[:file:M91FG123.png|Figure 4]]; Table 3). Relatively straight distributary channels building out into deep water will form more linear deposits known as bar fingers ([[:file:M91FG186.JPG|Figure 5]]).<ref name=Fisk_1961 />
{| class = "wikitable"
|-
|+ {{table number|3}}Statistics of dimensional data for deltaic sandstone bodies in meters.*
|-
! Sand body type || colspan="3" | Width || colspan="3" | Length || colspan="3" | Thickness ||
|-
! || Mean || Max. || Min. || Mean || Max. || Min. || Mean || Max. || Min. || N
|-
| Incised valleys || 9843 || 63,000 || 500 || - || - || - || 30.3 || 152 || 2 || 91
|-
| Fluvial channels || 755 || 1400 || 57 || - || - || - || 9 || 24 || 2.5 || 6
|-
| Distributary channels || 518 || 5900 || 20 || - || - || - || 7.8 || 40 || 1 || 268
|-
| All types of systems tracts || 25,365 || 106,000 || 1600 || 93,166 || 190,000 || 47,000 || 19.1 || 49 || 2.7 || 67
|-
| Highstand systems tract || 16,425 || 43,000 || 16,000 || - || - || - || - || - || - || 36
|-
| Transgressive systems tract || 7150 || 20,000 || 3300 || - || - || - || - || - || - || 5
|-
| Distributary mouth bars || 2868 || 14,000 || 1100 || 6477 || 9600 || 2400 || 9.7 || 42 || 1.2 || 26
|-
| Flood tidal delta complex || 6201 || 13,700 || 1700 || 12,300 || 25,700 || 2900 || 6.7 || 23 || 1.8 || 13
|-
| Crevasse channels || 58 || 400 || 5 || - || - || - || 2.4 || 17 || 0.2 || 44
|-
| Crevasse splays || 787 || 7700 || 18 || 5577 || 11,700 || 160 || 1.4 || 12 || 0.3 || 84
|-
| Lower tidal flat || 994 || 1550 || 400 || - || - || - || 4.6 || 9 || 2 || 14
|-
| Tidal creeks || 813 || 1550 || 161 || - || - || - || 5.2 || 18 || 1 || 15
|-
| Tidal inlet || 1850 || 2550 || 700 || 4300 || 4300 || - || 4.8 || 7 || 3 || 3
|-
| Estuary mouth shoal || 2400 || 2900 || 1700 || 3750 || 4700 || 2200 || 10 || 35 || 10 || 4
|-
| Chenier || 3650 || 6400 || 900 || 21,758 || 38,600 || 49,000 || 5.8 || 7 || 4.6 || 2
|-
| All sands || 5094 || 106,000 || 5 || 35,313 || 190,000 || 160 || - || - || - || 671
|-
| colspan="11" | *''From Reynolds.<ref name=Reynolds_1999 /> N = number.''
|}
[[file:M91FG187.JPG|thumb|300px|{{figure number|6}}Idealized log and permeability profiles for deltaic sand bodies (from Sneider et al.<ref name=Sneideretal_1978 />). Reprinted with permission from, and © by, the Society of Petroleum Engineers.]]
An upward-increasing grain size profile is characteristic for mouth bars. The lower parts are finer grained, more poorly sorted, and with common shale intercalations. Upward, the texture is coarser although there may be many laminations of clays and organic material. Permeability typically increases upward ([[:file:M91FG187.JPG|Figure 6]]).