Wolfcamp Upper A Fan Study

AAPG ACE2019 ANNUAL CONVENTION & EXHIBITION 19 22 May. San Antonio, Texas HIERARCHY OF DEEPWATER ELEMENTS COMBINE TO BUILD ARCHITECTURE OF DEEPWATER SYSTEM detail of low density & high density flow laminated sands of channel sheet elements fill with fluid escape channel sheet element fill of low density flow laminated & high density flow sands beds with fluid escape elements float in fine grained matrex represented by transparent areas architectural element set of nested stacked amalgamated channels vertical stacked cycles of channel fill elements dispersed & offset channel elements non-leveed "winged" channel fill element channel & sheet KEY slumps & sand elements debris flows overbank wings blanket fines C. Kendall & P. Haughton, 2008 Figures from: http://www.sepmstrata.org/page.aspx?&pageid=40&3 linear source devon point source source ramps Observation: Most of what is known about deep-water fans comes from siliciclastic-dominated systems Major mud-rich river delta Mud-rich systems Marsh Lagoon Valley anyon Lake Coastal delta lain and Shelf Slope apron Abandoned channel-levee Slide scars Slumps, Inner Lan-Mid-fan Basin valley High sinuosity channels and levees offe Low muddy coastal plain, deltas, cheniers system in subsurface Lateral feeding Muddy shelf Coastal plain Shelf Slope apron Arid Channel-levees in the sub-surface Heterogeneous depositional lobe sands & silts coastal plain Low gradient coastal plain Low anidur Slump scar Stump Turbidity cuments Slump Coastal plain Shelf Slope aprom Mud diapir Canyon fed by active nearshore littoral drift or relicit shelf sands Sandy coastal plain Sand-rich systems Barrier Longshore drift Slump scar Inner fan Mid-fan channelized suprafan lobe Alluvial fan Canyon 1000- 5000 m Coastal plain 2000 m Outer fan plain Shelf Basin plain Slope apron Slump Avalanching 10-50 km scar Slump 100-500 km Inertia flow Turbidity flow 5000 m 50-250 km Multiple rivers/sandy delta and coastal systems Coastal Himerland Proximal Med ramp Medial 1000 5000 m Braid Braid Shelf plnia sands Coalescing turbidite sands 10-100 km, Slides in the subsurface Distal ramp Braidplain Basin pla Sandy shelf Apron 10-50 km turbidites Basin plain 2000 m 5000 m Gravel-rich systems Swale Hummocks, lobes and plays 1-5 km 500 m Hilly hinterland Fan deltas Narrow shelf. Shoreline Inner-fan conglomerates and sandstones. Debris flows and high density turbidites Outer-fan mudstones and turbidites Line sourced talus cones, Line sourced coalescing alluvial fans Coalescing lobes Avalanching 1-10 km Inertia flow Turbidity flow Talus slopes urface plun Increasing size of source area, depositional system, size of flows, tendency for major slumps, persistence and size of fan-channels, channel-levee systems, tendency to meander, thin sheet-like sands in lower fan and basin plain 1-2 km Mid-fan high density turbidites Increasing dominance of a single feeder system, feeder channel stability, organization of depositional sequence, downcurrent length/width ratio, 'life time' of source area Decreasing grain size, slope gradient, frequency of flows, tendency for channels to migrate laterally After Stow & Mayall 2000 (based on Reading & Richards 1994 & Stow et al 1996)

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