Mass‐emplaced sand‐fingers at Mararoa construction site, southern New Zealand

Publisher Website
Google Scholar
Abstract
During work on a dam construction site in South Island, New Zealand, outflowing ground water resulted in extensive local mass‐transport of the sands being excavated. A series of small scale sand fans was built up, probably mainly by laminar mass‐flow processes. The surfaces of the fans were made up of a series of complexly interdigitating sand‐fingers that are inferred to have been emplaced by viscous plug‐flow. Other sedimentary processes associated with the building and synsedimentary destruction of the fans included rapid grain‐flow, liquefaction and progressive slumping. Although small in scale, the Mararoa mass‐flow fans may be a close analogue for some of the many‘fluxoturbidite’ or‘proximal flysch’ facies described in the sedimentological literature, and their geologic implications are therefore briefly discussed.