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Line 129: − M31F27.jpg|{{figure number|12}}Core photographs of subaqueous slump deposits. Diameter of cores A, B, and E is 13 cm (5 in.) and of cores C and D 8 cm (3 in.). A. X-ray radiograph of highly distorted clay layers in marine deposits beneath the slump block. B. X-ray radiograph of multiple fracturing in clays in the shear plane zone. C. X-ray radiograph of silt and sand core in the slump block. Note that bedding is preserved with only minor fracturing but is tilted at angles of 20 to 30°. D. X-ray radiograph of disturbed structures in mudflow deposit that caps a slump block. E. X-ray radiograph of core in normally deposited marine clays, which often cap the slump deposits. ote the lack of disturbance in these deposits. <ref name=Colemanetal_1981 /> Line 143:
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Line 154: − − <gallery mode=packed heights=200px widths=200px> − file:M31F28.jpg|{{figure number|13}}Part of a cored boring through a slump block composed of distributary mouth bars sands. This slump block is off Southwest Pass, Mississippi River delta, and is underlain and capped by marine clays. Diameter of cores is 8 cm (3 in.).<ref name=Colemanetal_1981 /> − file:M31F29.jpg|{{figure number|14}}Part of a core taken through a mudflow lobe on the continental shelf off the modern Mississippi River delta.<ref name=Colemanetal_1981 /> − </gallery>
→Subaqueous slump deposits
M31F25.jpg|{{figure number|10}}High-resolution seismic record run across an active growth fault seaward of the mouth of South Pass, Mississippi River delta. A. Seismic line showing active growth fault seaward of a large upslope mudflow. Note the increased thickness of sediment on the downthrown side of the fault. Horizontal scale is 300 m between shot points and vertical scale is 25 milliseconds per time line, or 19 m (62.5 ft). B. Detailed subbottom seismic record run across an active growth fault. Note the presence of a rollover structure and the increased accumulation of sedimentation on the downthrown side of the fault. Horizontal scale is 300 m between shot points and vertical scale is 10 milliseconds per time line, or 7.6 m (25 ft).<ref name=Colemanetal_1981 />
M31F25.jpg|{{figure number|10}}High-resolution seismic record run across an active growth fault seaward of the mouth of South Pass, Mississippi River delta. A. Seismic line showing active growth fault seaward of a large upslope mudflow. Note the increased thickness of sediment on the downthrown side of the fault. Horizontal scale is 300 m between shot points and vertical scale is 25 milliseconds per time line, or 19 m (62.5 ft). B. Detailed subbottom seismic record run across an active growth fault. Note the presence of a rollover structure and the increased accumulation of sedimentation on the downthrown side of the fault. Horizontal scale is 300 m between shot points and vertical scale is 10 milliseconds per time line, or 7.6 m (25 ft).<ref name=Colemanetal_1981 />
M31F26.jpg|{{figure number|11}}Summary diagram illustrating the major characteristics of slump deposits in the subaqueous delta plain.<ref name=Colemanetal_1981 />
M31F26.jpg|{{figure number|11}}Summary diagram illustrating the major characteristics of slump deposits in the subaqueous delta plain.<ref name=Colemanetal_1981 />
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Thus many sedimentary structures are the same as those described for distributary-mouth-bar deposits. Having been mass moved downslope, however, they lie on entirely marine clay deposits and thus normally have a sharp lower bounding surface. The upper surface is also usually extremely sharp and generally is characterized by a high degree of intensive burrowing on the top of the sand body. Because most of the deposits are mass moved, depositional dips increase significantly, and high-angle dips of 10 to 25° are not uncommon in these beds. Fracturing and localized faulting and slump structures are also abundant in most of the sand bodies.
Thus many sedimentary structures are the same as those described for distributary-mouth-bar deposits. Having been mass moved downslope, however, they lie on entirely marine clay deposits and thus normally have a sharp lower bounding surface. The upper surface is also usually extremely sharp and generally is characterized by a high degree of intensive burrowing on the top of the sand body. Because most of the deposits are mass moved, depositional dips increase significantly, and high-angle dips of 10 to 25° are not uncommon in these beds. Fracturing and localized faulting and slump structures are also abundant in most of the sand bodies.
<gallery mode=packed heights=300px widths=300px>
M31F27.jpg|{{figure number|12}}Core photographs of subaqueous slump deposits. Diameter of cores A, B, and E is 13 cm (5 in.) and of cores C and D 8 cm (3 in.). A. X-ray radiograph of highly distorted clay layers in marine deposits beneath the slump block. B. X-ray radiograph of multiple fracturing in clays in the shear plane zone. C. X-ray radiograph of silt and sand core in the slump block. Note that bedding is preserved with only minor fracturing but is tilted at angles of 20 to 30°. D. X-ray radiograph of disturbed structures in mudflow deposit that caps a slump block. E. X-ray radiograph of core in normally deposited marine clays, which often cap the slump deposits. ote the lack of disturbance in these deposits. <ref name=Colemanetal_1981 />
file:M31F28.jpg|{{figure number|13}}Part of a cored boring through a slump block composed of distributary mouth bars sands. This slump block is off Southwest Pass, Mississippi River delta, and is underlain and capped by marine clays. Diameter of cores is 8 cm (3 in.).<ref name=Colemanetal_1981 />
file:M31F29.jpg|{{figure number|14}}Part of a core taken through a mudflow lobe on the continental shelf off the modern Mississippi River delta.<ref name=Colemanetal_1981 />
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[[:file:M31F27.jpg|Figure 12A-E]] illustrates specific types of stratification often encountered in finer grained sequences separating slumped sand blocks. Both normal bedded marine clay deposits ([[:file:M31F27.jpg|Figure 12E]]) and highly distorted marine clays ([[:file:M31F27.jpg|Figure 12A, B, D]]) are common within the finer grained sequences.
[[:file:M31F27.jpg|Figure 12A-E]] illustrates specific types of stratification often encountered in finer grained sequences separating slumped sand blocks. Both normal bedded marine clay deposits ([[:file:M31F27.jpg|Figure 12E]]) and highly distorted marine clays ([[:file:M31F27.jpg|Figure 12A, B, D]]) are common within the finer grained sequences.
[[:file:M31F29.jpg|Figure 14]] represents a part of a core taken through a mudflow lobe that moved down from shallower waters in the delta front across the continental shelf and on to outer continental slope water depths. This particular mudflow consists primarily of fine-grained silty clays of the distal bar and prodelta clay deposits. As is evident in the core, a wide variety of distorted laminations are present. Numerous fractures exist throughout the entire deposit; however, this particular depositional lobe has moved downslope from water depths of approximately 20 m and now lies at the edge of the continental shelf, where water depths are about 130 m (downslope movement of approximately 3 to 4 km). Even with this magnitude of movement, primary stratification is still preserved within individual block , as shown in the cored boring in [[:file:M31F29.jpg|Figure 14]].
[[:file:M31F29.jpg|Figure 14]] represents a part of a core taken through a mudflow lobe that moved down from shallower waters in the delta front across the continental shelf and on to outer continental slope water depths. This particular mudflow consists primarily of fine-grained silty clays of the distal bar and prodelta clay deposits. As is evident in the core, a wide variety of distorted laminations are present. Numerous fractures exist throughout the entire deposit; however, this particular depositional lobe has moved downslope from water depths of approximately 20 m and now lies at the edge of the continental shelf, where water depths are about 130 m (downslope movement of approximately 3 to 4 km). Even with this magnitude of movement, primary stratification is still preserved within individual block , as shown in the cored boring in [[:file:M31F29.jpg|Figure 14]].
The lower two diagrams in [[:file:M31F26.jpg|Figure 11]] attempt to illustrate a sand isopach map associated with a growth fault offshore, and accumulation of slump-block material on the downthrown side of a growth fault. This type of isopach is common in many of the published papers discussing Tertiary depocenters. Variations in electric-log response in various parts of the isopach map are shown in the lower right-hand diagram of [[:file:M31F26.jpg|Figure 11]]. One of the most characteristic features of sand bodies deposited by slumping processes is the extremely blocky character of the electric-log response. Sands generally tend to be sharp based, producing rather uniform log response. Correlation of individual kicks on the sand body is extremely tentative simply because of the nature of the slumping process. It is the writers' belief that many of the sand bodies associated with growth fault systems represent shallow-water sand bodies that have slumped downslope into deeper water and become trapped on the seafloor near growth fault systems.
The lower two diagrams in [[:file:M31F26.jpg|Figure 11]] attempt to illustrate a sand isopach map associated with a growth fault offshore, and accumulation of slump-block material on the downthrown side of a growth fault. This type of isopach is common in many of the published papers discussing Tertiary depocenters. Variations in electric-log response in various parts of the isopach map are shown in the lower right-hand diagram of [[:file:M31F26.jpg|Figure 11]]. One of the most characteristic features of sand bodies deposited by slumping processes is the extremely blocky character of the electric-log response. Sands generally tend to be sharp based, producing rather uniform log response. Correlation of individual kicks on the sand body is extremely tentative simply because of the nature of the slumping process. It is the writers' belief that many of the sand bodies associated with growth fault systems represent shallow-water sand bodies that have slumped downslope into deeper water and become trapped on the seafloor near growth fault systems.