Changes

| Valley fills on bedrock unconformities || 12-1400 m (39-4593 ft); most < 500 m (1640 ft) || 75 m-52 km (246 ft-32 mi); most < 10 km (6 mi) || 2-870; highly variable; mainly 2-100

| Valley fills on bedrock unconformities || 12-1400 m (39-4593 ft); most < 500 m (1640 ft) || 75 m-52 km (246 ft-32 mi); most < 10 km (6 mi) || 2-870; highly variable; mainly 2-100

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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" | ¹''From Gibling,<ref name=Gibling_2006 /> Journal of Sedimentary Research. Reprinted with permission from, and &copy; by, the SEPM (Society for Sedimentary Geologists).''

| colspan="4" | ¹''From Gibling,<ref name=Gibling_2006 /> Journal of Sedimentary Research. Reprinted with permission from, and &copy; by, the SEPM (Society for Sedimentary Geologists).''

==Coarse-grained deltas==

==Coarse-grained deltas==

===Fan deltas===

===Fan deltas===

Fan deltas are coarse-grained deltas that form where alluvial fans deliver sediments into a lake or the sea. Geometries vary from wedging to tabular to sheet-like. Dreyer<ref name=Dreyer_1993>Dreyer, T., 1993, Geometry and facies of large-scale flow units in fluvial-dominated fan-delta-front sequences, in M. Ashton, ed., Advances in reservoir geology: Geological Society Special Publication 69, p. 135–174.</ref> described exposures of fan-delta sediments in the Miocene Ridge Route Formation of California as an analog for the Tilje Formation of the mid-Norwegian shelf. The main permeability barriers occur as transgressive prodelta mudstones separating individual regressive fan-delta sedimentary episodes. Minor heterogeneity within individual fan-delta mouth bars is provided by intramouth bar shales and carbonate-cemented sandstones.

Fan deltas are coarse-grained deltas that form where [[alluvial]] fans deliver sediments into a lake or the sea. Geometries vary from wedging to tabular to sheet-like. Dreyer<ref name=Dreyer_1993>Dreyer, T., 1993, Geometry and facies of large-scale flow units in fluvial-dominated fan-delta-front sequences, in M. Ashton, ed., Advances in reservoir geology: Geological Society Special Publication 69, p. 135–174.</ref> described exposures of fan-delta sediments in the Miocene Ridge Route Formation of California as an analog for the Tilje Formation of the mid-Norwegian shelf. The main permeability barriers occur as transgressive prodelta mudstones separating individual regressive fan-delta sedimentary episodes. Minor heterogeneity within individual fan-delta mouth bars is provided by intramouth bar shales and carbonate-cemented sandstones.

===Braid deltas===

===Braid deltas===

Four facies associations were defined:

Four facies associations were defined:

* Alluvial braided river, comprising stacked units of fine to coarse-grained, poorly sorted, cross-bedded sandstone. There are no shales present to act as permeability barriers to vertical flow. Excellent sweep could result from a wide well spacing in these rocks. However, there may be preferential flow through the coarser base of the sandstones, and the flood front could be unstable at the laminar scale as a result of grain size variation in the cross-beds.

* [[Alluvial]] braided river, comprising stacked units of fine to coarse-grained, poorly sorted, cross-bedded sandstone. There are no shales present to act as permeability barriers to vertical flow. Excellent sweep could result from a wide well spacing in these rocks. However, there may be preferential flow through the coarser base of the sandstones, and the flood front could be unstable at the laminar scale as a result of grain size variation in the cross-beds.

* Delta plain characterized by multistory sandstone channels and laterally extensive delta-plain siltstones. The bases of the channels commonly show silty conglomerate lags that are likely flow barriers or baffles. The persistent, thick siltstone intervals impart a strong degree of flow layering and create several stacked hydraulic units within this facies association.

* Delta plain characterized by multistory sandstone channels and laterally extensive delta-plain siltstones. The bases of the channels commonly show silty conglomerate lags that are likely flow barriers or baffles. The persistent, thick siltstone intervals impart a strong degree of flow layering and create several stacked hydraulic units within this facies association.

* Proximal delta front ([[:file:M91FG189.JPG|Figure 8]]). This comprises a series of thick mouth-bar sandstones and channel systems separated by extensive delta-front siltstones and mudstones. The latter can potentially form permeability barriers and create stacked hydraulic units.

* Proximal delta front ([[:file:M91FG189.JPG|Figure 8]]). This comprises a series of thick mouth-bar sandstones and channel systems separated by extensive delta-front siltstones and mudstones. The latter can potentially form permeability barriers and create stacked hydraulic units.