Pleistocene coastal terraces of Kaikoura Peninsula and the Marlborough coast, South Island, New Zealand

Abstract

Pleistocene marine terraces along the Marlborough coast, South Island, New Zealand, have been re‐examined with detailed stratigraphic observations, accurate height data, and amino acid and thermo‐luminescence (TL) geochronology. Marine terraces range in age from c. 220 ka (oxygen isotope stage 7) to c. 60 ka (oxygen isotope stage 3), in the area from Cape Campbell to Conway River. At Kaikoura Peninsula, five marine terraces are preserved. The marine fauna, loess stratigraphy, and amino acid dating of Tawera spissa, from the Kaikoura I (highest) terrace and from the highest terrace at Haumuri Bluffs (Tarapuhi Terrace), indicate a correlation to oxygen isotope substage 5c, with an age of 100 ka. North of the Clarence River, marine terraces (including the Parikawa Formation) are correlated to oxygen isotope substage 5e of the last interglacial. TL dating of loess supports this interpretation. The Winterholme Formation terrace at Kekerengu is reinterpreted as a last glaciation fluvioglacial terrace graded to a low‐stand of the sea. Therefore, we abandon the use of Winterholme and Parikawa Formations and, instead, correlate terraces to the geo‐chronometrically and astronomically tuned oxygen isotope chronology. Maximum late Pleistocene uplift rates vary from c. 2 m/ ka at Conway River, 1.3 m/ka at Haumuri Bluffs, 1.1 m/ka at Kaikoura, and 1.1 m/ka at Clarence River, to c. 0.5 m/ka in the Long Point area, c. 10 km south of Cape Campbell. Local structures, rather than regional uplift related to subduction, appear to be primarily responsible for uplift, and in at least three of the four areas, the causative faults are contractional fault/fold structures between or south of the major strike‐slip faults of the Marlborough fault system.