Unusual silty turbidites

Written by Kathryn Amos on . Posted in Research highlights

A new paper in Sedimentary Geology presents some great research describing interesting proximal silt-rich turbidites from the Secretary Basin, New Zealand. They're unusual, because silty turbidites are usually interpreted as distal marine deposits. This paper presents multibeam bathymetry and shallow sediment core data to present a suite of late Holocene proximal sandy-silt and silty-sand turbidites that contain negligible clay. The authors suggest that these deposits represent a previously undescribed suite of proximal continental slope deposits, based on their coarseness, sand-silt character, wide variety of bed types and inferred formative flow types. A range of non-cohesive flow processes are interpreted, with deposition from multi-phase and mixed-mode (ie both turbulent and laminar) flow. Flow partitioning is interpreted to most likely be the result of a variety of up-dip partial flow transformtations. This paper is a "must read" if you're interested in gravity flow processes and deposits!

Schematic diagrams of turbidity current processes. Figure taken from Strachan et al paper, link below.

Schematic diagrams of turbidity current processes. Figure taken from Strachan et al paper, link below.



http://www.sciencedirect.com/science/article/pii/S0037073816301506