Changes

The most common sedimentary structure consists of a variety of small-scale cross laminae and current ripple drift types ([[:file:M31F18.jpg|Figure 3G-I]]). Quite often mass-movement processes such as small localized slumps result in distorted laminations. This is particularly true near lower sections of the distributary-mouth-bar sequence, where over-pressured sediments are much more common. [[:file:M31F18.jpg|Figure 3G]] illustrates one type of slump structure commonly seen. Near the top of the distributary-mouth bar large accumulations of river-transported organic debris are often present. Water-saturated logs and other organic debris are transported down the rivers in times of flood and discharged into the nearshore zone, where wave action grinds down the coarser wood particles into large concentrations of organic debris. [[:file:M31F18.jpg|Figure 3I]] is a core showing some of the organic laminations present within the upper part of the sand body.

The most common sedimentary structure consists of a variety of small-scale cross laminae and current ripple drift types ([[:file:M31F18.jpg|Figure 3G-I]]). Quite often mass-movement processes such as small localized slumps result in distorted laminations. This is particularly true near lower sections of the distributary-mouth-bar sequence, where over-pressured sediments are much more common. [[:file:M31F18.jpg|Figure 3G]] illustrates one type of slump structure commonly seen. Near the top of the distributary-mouth bar large accumulations of river-transported organic debris are often present. Water-saturated logs and other organic debris are transported down the rivers in times of flood and discharged into the nearshore zone, where wave action grinds down the coarser wood particles into large concentrations of organic debris. [[:file:M31F18.jpg|Figure 3I]] is a core showing some of the organic laminations present within the upper part of the sand body.

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file:M31F19.jpg|{{figure number|4}}Part of a continuously cored boring through the distributary-mouth bar sequence. This section represents the lower part of the distal bar deposit. Diameter of cores is 8 cm (3 in.).<ref name=Colemanetal_1981>Coleman, J. M., and D. B. Prior, 1981, Deltaic environments of deposition ''in'' P. A. Scholle and D. Spearing, eds., Sandstone depositional environments: AAPG Memoir 31, p. 139-178.</ref>

file:M31F19.jpg|{{figure number|4}}Part of a continuously cored boring through the distributary-mouth bar sequence. This section represents the lower part of the distal bar deposit. Diameter of cores is 8 cm (3 in.).<ref name=Colemanetal_1981>Coleman, J. M., and D. B. Prior, 1981, Deltaic environments of deposition ''in'' P. A. Scholle and D. Spearing, eds., Sandstone depositional environments: AAPG Memoir 31, p. 139-178.</ref>

file:M31F20.jpg|{{figure number|5}}Part of a continuously cored boring through the distributary-mouth bar sequence. This section represents the lower part of the distributary-mouth bar deposit. Diameter of cores is 8 cm (3 in.).<ref name=Colemanetal_1981 />

file:M31F20.jpg|{{figure number|5}}Part of a continuously cored boring through the distributary-mouth bar sequence. This section represents the lower part of the distributary-mouth bar deposit. Diameter of cores is 8 cm (3 in.).<ref name=Colemanetal_1981 />