Quaternary faulting in the offshore Flaxbourne and Wairarapa Basins, southern Cook Strait, New Zealand

Abstract Marine seismic reflection profiles, bathymetric data, and seabed samples reveal the stratigraphy and Quaternary structure of the southern Wairarapa and Flaxbourne Basins in southeastern Cook Strait and eastern Marlborough. These SW‐NE‐trending basins began forming before the late Miocene (>10 Ma), but their development has been mainly during and since that time and continues today within the Pacific‐Australia plate boundary zone. Recently active structures deforming and bounding the basins are recognised by growth strata and deformation of Quaternary sediments. Observed structural geometries reflect Pliocene‐Recent changes in the kinematics of faulting in central New Zealand. The 12–22 km wide southern Wairarapa Basin contains up to c. 2.9 km of strata and is deforming between offshore segments of the dextral strike‐slip Wairarapa Fault and associated Wharekauhau Thrust on the western margin, and offshore extensions of the Aorangi Mountains range‐front reverse faults on the eastern margin. To the...