Changes

[[file:sedimentary-basin-analysis_fig4-35.png|thumb|300px|{{figure number|2}}After Bartec et al.).<ref name=ch04r17>Bartek, L., R., Vail, P., R., Anderson, J., B., Emmet, P., A., Wu, S., 1991, The effect of Cenozoic ice sheet fluctuations on the stratigraphic signature of the Neogene, in Cloetingh, S., ed., Long Term Sea Level Changes: Journal of Geophysical Research, vol. 96, 6753–6778.</ref> Copyright: Journal of Geophysical Research.]]

[[file:sedimentary-basin-analysis_fig4-35.png|thumb|300px|{{figure number|2}}After Bartec et al.).<ref name=ch04r17>Bartek, L., R., Vail, P., R., Anderson, J., B., Emmet, P., A., Wu, S., 1991, The effect of Cenozoic ice sheet fluctuations on the stratigraphic signature of the Neogene, in Cloetingh, S., ed., Long Term Sea Level Changes: Journal of Geophysical Research, vol. 96, 6753–6778.</ref> Copyright: Journal of Geophysical Research.]]

[[:file:sedimentary-basin-analysis_fig4-35.png|Figure 2]] shows the depositional geometry of third-order cycles stacked into a second-order transgressive/regressive cycle. Each third-order cycle is represented by a depositional sequence composed of three phases (Figure 4-18). The lowstand phase may consist of basinal sand-prone mounds (basin-floor fans) and shelf-edge deltas. The transgressive phase is usually dominated by regional mudstones. The highstand most often consists of prograding fluvial and deltaic sediments forming broad coastal plains with potential sandstone reservoir facies.

[[:file:sedimentary-basin-analysis_fig4-35.png|Figure 2]] shows the depositional geometry of third-order cycles stacked into a second-order transgressive/regressive cycle. Each third-order cycle is represented by a depositional sequence composed of three phases (Figure 4-18). The lowstand phase may consist of basinal sand-prone mounds (basin-floor fans) and shelf-edge deltas. The transgressive phase is usually dominated by regional mudstones. The highstand most often consists of [[Well_log_sequence_analysis#Parasequence_stacking_patterns|prograding]] fluvial and deltaic sediments forming broad coastal plains with potential sandstone reservoir facies.

In carbonate-prone depositional settings, the transgressive-to-highstand phases may be dominated by regionally extensive carbonate platforms. The mudstone-dominated transgressive deposits can provide potential hydrocarbon source rocks, especially in the third-order transgressive phases composited within the second-order transgressive phase. In contrast, the dominance of third-order regressive phases within the second-order regression brings more potential reservoir sand progressively further into the basin. Optimal hydrocarbon traps form where the regressive sandstones are in close proximity to organic-rich transgressive mudstones and are overlain by effective top seal.

In carbonate-prone depositional settings, the transgressive-to-highstand phases may be dominated by regionally extensive carbonate platforms. The mudstone-dominated transgressive deposits can provide potential hydrocarbon source rocks, especially in the third-order transgressive phases composited within the second-order transgressive phase. In contrast, the dominance of third-order regressive phases within the second-order regression brings more potential reservoir sand progressively further into the basin. Optimal hydrocarbon traps form where the regressive sandstones are in close proximity to organic-rich transgressive mudstones and are overlain by effective top seal.