Geological structure of Wairarapa Valley, New Zealand, from seismic reflection profiling

Deformation style and history of the Eketahuna region, Hikurangi forearc, New Zealand, from shallow seismic reflection data

“…The Eketahuna Group (Te) sediments are fine-grained sandstone, siltstone, mudstone, and turbidite units, and the Makuri Group (Tmk) comprises shallow water shelly sandstones interbedded with limestones. Stratigraphy of the Eketahuna Basin is similar to that of the Dannevirke and Wairarapa Basins to the north and south along the Hikurangi forearc (Wells 1989;Cape et al 1990;Melhuish 1990), with the exception that Miocene strata are less widespread and Pliocene-Pleistocene strata are thicker in the Dannevirke Basin.…”

“…To the north, Melhuish (1990) described moderate to steeply dipping reverse faults offsetting a sequence of Pliocene-Pleistocene sediments in the Dannevirke Basin, which is contiguous with the Eketahuna Basin. To the south, Cape et al (1990) have described the Wairarapa Fault and associated deformation as a flower structure, consistent with the Wairarapa Fault having strikeslip motion, and several open folds and reverse faults to the east, within the forearc basin.…”

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

“…Stratal geometry across the faults indicates negligible thrust fault and fold growth during deposition of most of the late Miocene strata, although extensional growth faulting may have occurred on one of the faults prior to reflector eTt (centre of profile A). The thrusts therefore developed predominantly since the late Miocene, an observation consistent with many other contractional structures within the Wairarapa Basin (Cape et al 1990;Beanland 1995;Lamarche et al 1995;Nicol et al 1996). The faults, however, have no bathymetric expression (Fig.…”

“…Significant subsidence and sedimentation was occurring in the southern forearc Wairarapa Basin during the late Miocene (Cape et al 1990;Lamarche et al 1995;Beanland 1995), but the vertical separation on major structures imaged in the profiles beneath Palliser Bay is largely post-Miocene age (<5 Ma) and on many of the faults it could be Pleistocene ( Fig. 6,7; profiles A-D).…”

“…It has been commonly argued that the Hikurangi margin was dominated by thrust faulting, folding, and tectonic imbrication throughout the Neogene and that strike-slip faults have not played a major role in the tectonic development of eastern Wairarapa (e.g., Pettinga 1982;Cape et al 1990;Chanier & Ferriere 1991;Rait et al 1991;Rait 1997). Beanland (1995) considered that: (1) although the azimuth of PacificAustralian plate motion has changed during the Neogene, the relative plate motion remained approximately perpendicular to the clockwise-rotating margin until 4-2 Ma, such that there was no requirement for an older dextral fault belt in the east coast ranges (Fig.…”