Factors influencing sediment supply, deposition, accommodation and stabilization

Climate

• Arid during glacial periods (low sea level) (Rankey,1997; Soreghan, 2002 )
• More humid during interglacial periods (high sea level)
• Monsoonal precipitation patterns (dry winters, wetter summers)
• Prevailing winds from present-day west during winter and east during summer (Parrish and Patterson, 1988)

Geometry of shelf and forced sea level changes

• Extremely low relief, 30 meters from updip margin to position of steepened slope downdip; estimated by considering Wolfcamp isopach, position of marine carbonate pinchout and a faunal depth indicator (fusulinids)
• Rapid absolute sea level changes (forced) due to glacial cycles

Proximity to probable siliciclastic source (Ancestral Rocky Mountains)

• 250 kilometers to western margin
• 330 kilometers to steepened slope marginal to the Anadarko Basin

End members of the cycles

Interglacial (low sea level)

• Continental conditions on the Kansas shelf
• Relatively high siliciclastic sediment supply
• Cg silts and vfg sands available from source due to arid conditions
• Monsoonal patterns (dry winters and wetter summers) and prevailing winds (present-day westerly in winter and easterly in summer) were synchronized for optimal sediment supply by wind and optimal biostabilization of eolian sediments.
• Wetter months supported at least intermittent vegetative cover, support for burrowing animals, soil moisture, intermittent mobile water (gleying) and high water tables

Glacial (high sea level)

• Marine conditions on Kansas shelf except in areas above updip margin
• Relatively low siliciclastic sediment supply
• Cg silts and vfg sands stabilized closer to source during more humid conditions
• Only fg silts and clay in low volumes were delivered to the Kansas shelf

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Last Modified November 2005