Channel Belt Architecture and Geometry- A Function of Depositional Parasequence Set Stacking Pattern, Ferron Sandstone, East-Central Utah: ABSTRACT

Abstract

SUMMARY Ferron Sandstone fluvial-deltaic parasequence sets exhibit a well-developed seaward-stepping, aggradational , and landward-stepping pattern. Detailed mapping has quantified the architecture and geometry of fluvial channel belts, as a function of parasequence set stacking patterns. Channel belts within the seaward-stepping parasequence sets, formed in river-dominat ed deltas, when the available sediment supply exceeded the available accommodation space. They have vertically stacked internal channel-fill elements. Thicknesses from 10-15 feet and 4045 feet and widths from 300-700 feet and 1200-1400 feet are most common. Width/thickness aspect ratios range from 7.8-52.9 and average about 29.5. Channel belts bifurcate as they approach the paleo-shoreline and become narrower, averaging 638 feet in width, with lower aspect ratios, averaging about 16.6. Channel belts within the aggradational parasequence sets, formed in more stormdominated deltas, when the sediment supply was balanced with rate of development of accommodation space. They have laterally stacked channel-fill elements. Thicknesses from 25-35 feet and 55-60 feet and widths from 1250-1900 feet are most common. Aspect ratios range from 31.9-97.4 and average about 57.2. Channel belts closer to the paleoshoreline have aspect ratios averaging about 12.0. Channel belts within back-stepping parasequence sets, formed in wave-dominated deltas, when the available sediment supply was less than the available accommodation space. They range in thickness from 9-27 feet and 749-2652 feet in width, with vertically stacked elements. Aspect ratios of 6590 and 185-195 are most common. Construction of geologic models of fluvial-delta ic channel belt reservoir systems must honor changes in architecture and geometry as a function of parasequence set stacking patterns and utilize realistic architectural objects.