Faulting in Banks Peninsula: tectonic setting and structural controls for late Miocene intraplate volcanism, New Zealand

Abstract

An analysis of faulting in the late Miocene volcanic rocks of Banks Peninsula, South Island, New Zealand, shows that the formation of the volcanic edifice was largely controlled by NE–SW-striking dextral-oblique strike-slip faults. The data show a variable component of west–east- or NW–SE-oriented shortening and north–south or NE–SW extension. Synvolcanic faults reactivated Cretaceous normal faults and are interpreted to have formed a local pull-apart basin that controlled volcanism. Further east, the geometry of Akaroa Harbour is controlled by a north–south-striking oblique reverse fault. Limited fault-slip data collected from sub-recent loess deposits are not significantly different from the data collected in the volcanic rocks and appear to show that the kinematic field did not change significantly over the last c . 10 Ma. The overall kinematic field causing the recent series of earthquakes in the greater Christchurch region is also not fundamentally different from the one that controlled the eruption of the volcanic rocks. We conclude that the inherited Cretaceous faults controlled the development of the late Miocene volcanism on Banks Peninsula and largely provided a major anisotropy along which the recent faults ruptured.

Development of a 3D Velocity Model of the Canterbury, New Zealand, Region for Broadband Ground‐Motion Simulation

“…The Rakaia basin is relatively constrained by the Indopacific Rakaia River lines. Another apparent feature in the top Basement surface is the structural high that is connected with the late Miocene-Pliocene volcanism in the Banks Peninsula area (Ghisetti and Sibson, 2012;Hampton, 2010;Ring and Hampton, 2012;Sewell, 1988). The Basement surface (as well as the other surfaces) shows the bulge associated with the double volcanic edifice structure where the Lyttelton and Akaroa volcanoes lie (Sewell, 1988;Sewell et al, 1993).…”

“…The late Miocene-Pliocene BPV (11-6 Ma) (Forsyth et al, 2008), located south of Christchurch city represent a geologically significant feature (Hampton, 2010;Ring and Hampton, 2012;Sewell, 1988) which must be considered in the velocity model of the Canterbury region. These volcanic rocks have a significantly higher velocity (i.e.…”

“…The elevation of the Basement in the Lyttelton structure is inferred to reach a higher elevation than in the Akaroa structure as constrained from Basement outcropping at Gebbies pass as a result of the Gebbies Pass fault system (Forsyth et al, 2008;Ring and Hampton, 2012). The 'saddle' structure of the Basement surface between Rolleston and Darfield is a feature which arises as a consequence of the raised elevation of the Banks Peninsula and Southern Alps areas.…”

Seismic Anisotropy and Stress of the Canterbury Plains

“…Quigley et al (2010). Dashed black lines are inferred faults mapped by Beavan et al (2010Beavan et al ( , 2011 and Ring and Hampton (2012). Coloured triangles represent VUW temporary stations (yellow), GNS temporary stations (brown) and GeoNet permanent stations (blue).…”

“…Solid red lines are faults, with the Greendale fault in the centre from(Quigley et al, 2010). Thin and dashed red lines are active faults and late Cretaceous normal faults respectively(Ring and Hampton, 2012). Dashed black lines are buried faults from(Beavan et al, 2010(Beavan et al, , 2011.…”