RT Journal Article SR Electronic(1) A1 Plenderleith, Gayle E. A1 Dodd, Thomas J. H. A1 McCarthy, Dave J.YR 2022 T1 The effect of breached relay ramp structures on deep‐lacustrine sedimentary systems JF Basin Research, VO 34 IS 3 SP 1191 OP 1219 DO https://doi.org/10.1111/bre.12655 PB European Association of Geoscientists & Engineers, SN 1365-2117, AB [Abstract Fault relay ramps are important sediment delivery points along rift margins and often provide persistent flow pathways in deepwater sedimentary basins. They form as tilted rock volumes between en‐echelon fault segments, which become modified through progressive deformation, and may develop through‐going faults that ‘breach’ the relay ramp. It is well established that hinterland drainage (fluvial/alluvial systems) is greatly affected by the presence of relay ramps at basin margins. However, the impact on deepwater (deep‐marine/lacustrine) subaqueous sediment gravity flow processes, particularly by breached relay ramps, is less well documented. To better evaluate the complex geology of breached relay settings, this study examines a suite of high‐quality subsurface data from the Early Cretaceous deep‐lacustrine North Falkland Basin (NFB). The Isobel Embayment breached relay‐ramp, an ideal example, formed during the syn‐rift and was later covered by a thick transitional and early post‐rift succession. Major transitional and early post‐rift fan systems are observed to have consistently entered the basin at the breached relay location, directed through a significant palaeo‐bathymetric low associated with the lower, abandoned ramp of the structure. More minor systems also entered the basin across the structure‐bounding fault to the north. Reactivation of basin‐bounding faults is shown by the introduction of new point sources along its extent. This study shows the prolonged influence of margin‐located relay ramps on sedimentary systems from syn‐rift, transitional and into the early post‐rift phase. It suggests that these structures can become reactivated during post‐rift times, providing continued control on deposition and sourcing of overlying sedimentary systems. Importantly, breached relays exert control on fan distribution, characterised by laterally extensive lobes sourced by widespread feeder systems, and hanging walls settings by small‐scale lobes, with small, often line‐sourced feeders. Further characterising the likely sandstone distribution in these structurally complex settings is important as these systems often form attractive hydrocarbon reservoirs., Early post‐rift deposition associated with the breached relay structure can be divided into two domains: (1) systems which entered the basin at the breached relay structure via the lower abandoned ramp; (2) systems which entered directly across the hangingwall of structure bounding faults. Into the early post‐rift, systems continue to enter at the same locations, however, fan geometries and sources change in response to overall basin subsidence becoming the main accommodation driver. ], UL https://www.earthdoc.org/content/journals/10.1111/bre.12655