Wolfcamp Upper A Fan Study

AAPG ACE2019 ANNUAL CONVENTION & EXHIBITION 19 22 May San Antonio, Texas FLOW TYPE DEBRIS FLOW COMPOSITE/ CO-GENETIC FLOWS HIGH-DENSITY TURBIDITY CURRENT LOW-DENSITY TURBIDITY CURRENT NON-COHESIVE MIXED COHESIVE FLOW STRUCTURE Depth Depth BEHAVIOUR Laminar Depositional processes - Facies in Wolfcamp mixed carbonate-siliciclastic fan are dominated by sediment gravity flow deposits DEPOSITS Turbulent Flow Flow Debrite H5 H4 Velocity Megabed 'Linked' debrite H2 Hybrid event beds 'Banded' sandstone High-density turbidite Velocity Low-density turbidite H1 H3 5 cm 10 m thick 2 inches -> 32 ft thick DIVISIONS Pseudonodular and/or massive mud Parallel and ripple cross-lamination Muddy sand +/- mudclasts, sand patches, injections, outsized granules, shear fabrics; often segregation of plant fragments to top INTERPRETATION Suspension fallout+/- shearing Traction by dilute turbulent wake Cohesive debris flow, locally modified by sand injection from beneath, and partly reworked at top Alternating lighter and darker sands, with loading at base of lighter layers; sheared dewatering pipes and sheets Transitional flow with intermittent turbulence suppression due to near-bed dispersed clay and internal shearing Isolated mudclasts surrounded by clean sandstone Graded to ungraded, structureless and dewatered, relatively clean sand, commonly with isolated floating mudclasts at top current Progressive aggradation beneath non-cohesive high-density turbidity devon From Haughton et al., 2009, Hybrid sediment gravity flow deposits - classification, origin and significance: Marine and Petroleum Geology, v. 26, p. 1900-1918.

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