Bottom Current Modification of Turbidite Lobe Complexes

• DOI: 10.3389/feart.2021.752066
• Publication Date: 2022-02-21T11:06:00Z
• Authors: A. Fuhrmann; I. A. Kane; E. Schomacker; M. A. Clare; Anna Pontén
• Keywords: Contourite; Turbidity current; Seafloor Spreading; Shoal; Gravity current

Submarine lobes form at the distal end of sediment gravity flow systems and are globally important sinks for sediment, anthropogenic pollutants organic carbon, as well forming hydrocarbon CO 2 reservoirs. Deep-marine, near bed or bottom currents can modify pathways distribution by directly interacting with modifying seafloor morphology. Deciphering nature gravity- interaction, particularly in ancient systems, remains a challenge due to lack integrated datasets necessary oceanographic framework. Here we analyse high-resolution 3D seismic reflection core data from Upper Cretaceous interval offshore Tanzania reveal interaction turbidite fine-grained waves contourite drift deposits. Contourite morphology governs large-scale confinement style shape that range frontally confined crescent shaped, laterally elongated, semi-confined lobes. Core reveals massive cross-laminated high density turbidites lobe axis position show no direct between flows contour currents. Lobe off-axis fringe deposits consist parallel- ripple-laminated, low turbidites, which inter-bedded bioturbated, muddy siltstones represent toes drifts. Starved ripples, streaks up sandstone above individual beds indicate reworking This facies reflects temporal quasi-steady turbidity interact topography build over short periods time. Frontally fill-and-spill fashion, causes rapid deposition obscures any current signal. Lateral increased runout length, promotes development fringes proportion reworked sands. During times when subordinate, contourites accumulate on top lobe, confining next thus overall stacking pattern complex. Although volumes these modified complexes comparable other deep-marine considerably influence deposit architecture.