Evento
Early post-rift facies and architectural changes within a coarse-grained deepwater system deposited above a Mass Transport Complex (MTC)
Tipo del evento:
Reunión
Nombre del evento:
British Sedimentological Reseach Group 55th Annual General Meeting
Fecha del evento:
18/12/2016
Institución Organizadora:
British Sedimentological Reseach Group;
Título del Libro:
British Sedimentological Reseach Group 55th Annual General Meeting. Abstract Volume
Editorial:
British Sedimentological Research Group
Idioma:
Inglés
Clasificación temática:
Resumen
Local gradient changes and variable accommodation characterize the upper surface of mass transport complexes (MTCs). Bathymetric variability can influence the longitudinal and vertical processes occurring within coarse-grained sediment gravity flows, which are challenging to interpret from the rock record alone. A 60 m thick succession of very coarse-grained and poorly-sorted matrix-rich sandstones deposited above a seismic-scale mass transport complex (MTC) is investigated in the Jurassic stratigraphy of the Los Molles Formation, Neuquén Basin. The facies types and architectural changes documented within the deep-water succession provide insights into the interactions between coarse-grained sediment gravity flows and uneven seabed inherited from the top of a MTC. The succession was deposited in the Chacay Melehue hemi-graben outcrops along a 6.5 km long oblique downdip longitudinal profile which permitted correlation of individual beds between 16 stratigraphic sections (1:25 scale). Two units are defined: Unit 1 comprises heterolithic facies grading upwards into poorly sorted, very coarse- to fine-grained, thin- to medium-bedded sandstones with abundant pebble-sized clasts; Unit 2 comprises three thick conglomeratic event beds of very poorly-sorted, granular to medium-grained mud-rich sandstone matrix, supporting polygenic gravels ranging from pebble to boulder and large clasts.The sandstone-rich division of the deep-water succession studied is interpreted as a lobe complex emplaced by an out-of-equilibrium sand-rich system, which recorded a progressive decrease of confinement from Unit 1 to Unit 2. The MTD-related topography controlled stratigraphic trapping of considerable sand volumes in Unit 1. Once the MTC-related accommodation was filled, relief associated with individual supra-MTC sandbodies produced subtle changes in depositional processes in the Unit 2. Predictive stratigraphic outcrop-based models can provide insights into spatial distribution and internal architecture of heterogeneous sandbodies able to generate multiscale net/gross variations that make-up the internal complexity of subsurface reservoirs hosted in lobes above MTCs.
Palabras clave:
EARLY POST-RIFT
,
DEEP-WATER FACIES
,
FLOW BEAHVIOUR
,
MTC
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Colecciones
Eventos(CIG)
Eventos de CENTRO DE INVEST.GEOLOGICAS (I)
Eventos de CENTRO DE INVEST.GEOLOGICAS (I)
Citación
Early post-rift facies and architectural changes within a coarse-grained deepwater system deposited above a Mass Transport Complex (MTC); British Sedimentological Reseach Group 55th Annual General Meeting; Cambridge; Reino Unido; 2016; 53-53
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