Page 236 - Global Tectonics

222 CHAPTER 8

Five Fingers Five Fingers Dagg Ridge
(a) Basin Dagg Basin (b) Basin Breaksea Basin Dagg Basin

N
(c)
Alpine Fault 4km

Footwall extension
outside releasing
bend 0
Releasing 10km
Present Dagg Basin bend
depocenter
Sediment

Channels transport 0
abundant glacial
sediment supply
to basin.

Dagg Ridge
Transpressional
push - up and
basin inversion

Figure 8.10 Sketches showing the progressive evolution of the Resolution segment of the Alpine Fault near Fiordland
at (a) ∼1 Ma when a series of pull-apart basins formed between extensional step-overs and (b) presently when linkages
among faults have cut through the Dagg Basin forming the Dagg Ridge (shaded) (after Barnes et al., 2005, with
permission from the Geological Society of America). (c) Schematic block diagram showing the three-dimensional
geometry of adjacent releasing and restraining bends (image provided by P. Barnes and modified from Barnes et al.,

2001, with permission from Elsevier). Southern end of basin displays a positive flower structure, push-up, and
transpression. Northern end of basin displays pull-apart basin, subsidence, and transtension.

braided pattern in plan view. The faults that reversed oblique-slip fault forms. Signifi cant
most closely follow the direction of plate rotations about vertical or near vertical axes
movements predominate, grow longer, and also commonly occur (Section 8.5). At the ends
assume near vertical dips. Other faults at an of large strike-slip faults, displacements may be
angle to the overall direction of movement dissipated along arrays of curved faults that
may then rotate farther out of alignment and link to the main fault forming fans or horsetail
develop dips significantly less than vertical, so splays (Fig. 8.5c). These structures may

that the fault involves a component of dip-slip record either contractional or extensional
motion. If the fault’s curvature carries it to a deformation according to the geometry of the
region of extension, a normal oblique-slip fault curvature and the sense of motion on the main
develops; if to a region of compression, a fault.