Trough-mouth fans (TMFs) are large depocentres of glacially influenced sediments formed at the mouths of some glacially carved cross-shelf troughs (Vorren et al. 1989). They develop in front of ice streams grounded at, or near to, the shelf edge, which transported large volumes of glacigenic sediment to the outer shelf and upper slope. The main components of TMFs are prograding outer shelf–upper slope strata which are constructed largely of foresets comprising debris-flow units. They are commonly capped by topsets that may include subglacially deposited tills (Fig. 1f). Mass-wasting deposits, gullies and channels may also occur in conjunction with or within the TMFs.
Components of the Crary Fan. (a) Oblique view of Crary Fan and Filchner Trough from IBCSO bathymetry. Note the convex-outward shape of the fan. (b) Multibeam-bathymetric image showing slab. Acquisition system Kongsberg EM122. Frequency 12 kHz. Grid-cell size 30 m. (c) Multibeam-bathymetric image showing submarine landslide. Acquisition system as for (b). (d) Seafloor depth profile across submarine landslide scar. Location in (a). VE×28. (e) Sub-bottom profile of debris-flow deposit. Location in (a). Acquisition system Kongsberg TOPAS PS 018. Frequency 18 kHz. Secondary beam frequency …
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