|A storm-dominated inner shelf, western Cook Strait, New Zealand|
Lewis, K.B. (1979). A storm-dominated inner shelf, western Cook Strait, New Zealand. Mar. Geol. 31(1-2): 31-43
In: Marine Geology. Elsevier: Amsterdam. ISSN 0025-3227; e-ISSN 1872-6151, meer
Beddingvorm; Geomorfologie; Platendynamiek; Sedimentverdeling; Stormen; Marien
In the exposed, western approaches to Cook Strait, westerly storms are considered to have generated southeastward-moving, coast-parallel currents which have been responsible for the formation and maintenance of stable ridges of black, mafic sand and ephemeral ribbons of light, felsic sand. These bedforms are examined using side-scan sonographs. The black sand ridges probably formed 12,000 to 9000 years ago as 'shoreface connected shoals'. Since inundation by rising sea level, their form has been perpetuated by occasional storm-generated currents, the only strong currents in the area. Formation ceased about 9000 years ago when rock promontories to the west began to act as natural barriers to the rapid longshore supply of black sand. The light sand ribbons represent the feather edge of a seaward-migration prism of fine, mobile, river-derived, sand. During prolonged storms, wind drift and storm surge currents drive the sand in ribbons along the rippled, shell-and-black-sand-floored troughs between ridges.