Changes

==Effect on reservoir deposition==

==Effect on reservoir deposition==

[[file:sedimentary-basin-analysis_fig4-40.png|300px|thumb|{{figure number|3}}Relationship between 23 fields in the High Island–East Breaks depocenter that produce from the ''Glob alt'' sandstones and the ''Glob alt sandstone'' 200-ft (60-m) isopach.]]

The lowstand phase of the ''Glob alt'' depositional sequence is sand prone ([[:file:sedimentary-basin-analysis_fig4-29.png|Figure 3]]) and produces hydrocarbons from at least 23 fields within the High Island–East Breaks depocenter ([[:file:sedimentary-basin-analysis_fig4-40.png|Figure 4]]). The sandstone reservoirs were deposited within slope valleys by gravity-flow processes.<ref name=ch04r7>Armentrout, J., M., 1991, Paleontological constraints on depositional modeling: examples of integration of biostratigraphy and seismic stratigraphy, Pliocene–Pleistocene, Gulf of Mexico, in Weimer, P., Link, M., H., eds., Seismic Facies and Sedimentary Processes of Submarine Fans and Turbidite Systems: New York, Springer-Verlag, p. 137–170.</ref> The abundance of ''Glob alt'' sandstone is interpreted to be the consequence of a major fall in relative sea level. The falling sea level resulted in enhanced bypass of sand across the shelf and into the slope basins and deposition of a lowstand systems tract.

The lowstand phase of the ''Glob alt'' depositional sequence is sand prone (Figure 4-29) and produces hydrocarbons from at least 23 fields within the High Island–East Breaks depocenter ([[:file:sedimentary-basin-analysis_fig4-40.png|Figure 3]]). The sandstone reservoirs were deposited within slope valleys by gravity-flow processes.<ref name=ch04r7>Armentrout, J., M., 1991, Paleontological constraints on depositional modeling: examples of integration of biostratigraphy and seismic stratigraphy, Pliocene–Pleistocene, Gulf of Mexico, in Weimer, P., Link, M., H., eds., Seismic Facies and Sedimentary Processes of Submarine Fans and Turbidite Systems: New York, Springer-Verlag, p. 137–170.</ref> The abundance of ''Glob alt'' sandstone is interpreted to be the consequence of a major fall in relative sea level. The falling sea level resulted in enhanced bypass of sand across the shelf and into the slope basins and deposition of a lowstand systems tract.

The ''Glob alt'' sequence mapped on [[:file:sedimentary-basin-analysis_fig4-29.png|Figure 3]] represents the lowstand depositional phase of the Haq et al.<ref name=ch04r43 />) third-order 3.7 cycle (Figure 4-25). Cycle 3.7 begins with the most significant relative fall in sea level of the Tejas B-3 supersequence after the second-order highstand (cycles 3.4 and 3.5). This significant fall in sea level resulted in transport of large volumes of sand from the paleo-Mississippi River system into the slope basins of the High Island and East Breaks areas of offshore Texas ([[:file:sedimentary-basin-analysis_fig4-29.png|Figures 3]] and [[:file:sedimentary-basin-analysis_fig4-33.png|5]]), depositing numerous potential reservoirs of gravity-flow sands during maximum amplification of falling sea level. Following lowstand deposition, relative rise in sea level cut off the sand supply and resulted in deposition of hemipelagic mudstones, forming a regional top seal to the ''Glob alt'' sandstones ([[:file:sedimentary-basin-analysis_fig4-29.png|Figures 3]] and [[:file:sedimentary-basin-analysis_fig4-33.png|5]]). The top seal is a condensed section that correlates laterally with the transgressive and early highstand systems tracts.

 

The ''Glob alt'' sequence mapped on Figure 4-29 represents the lowstand depositional phase of the Haq et al.<ref name=ch04r43 />) third-order 3.7 cycle (Figure 4-25). Cycle 3.7 begins with the most significant relative fall in sea level of the Tejas B-3 supersequence after the second-order highstand (cycles 3.4 and 3.5). This significant fall in sea level resulted in transport of large volumes of sand from the paleo-Mississippi River system into the slope basins of the High Island and East Breaks areas of offshore Texas (Figures 4-29 and 4-33), depositing numerous potential reservoirs of gravity-flow sands during maximum amplification of falling sea level. Following lowstand deposition, relative rise in sea level cut off the sand supply and resulted in deposition of hemipelagic mudstones, forming a regional top seal to the ''Glob alt'' sandstones (Figures 4-29 and 4-33). The top seal is a condensed section that correlates laterally with the transgressive and early highstand systems tracts.

==See also==

==See also==