GLORIA — GEOMAR Library Ocean Research Information Access

Hits per page

hits 1 - 2 | 2 hits

Sorting

Electronic Resource

Sheet slides and rotational failures on a convergent margin: the Kidnappers Slide, New Zealand (1991)

BARNES, PHILIP M. ; LEWIS, KEITH B.

Oxford, UK : Blackwell Publishing Ltd

Sedimentology 38 (1991), S. 0

add to mindlist on the mindlist

Details

ISSN: 1365-3091

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Geosciences

Notes: The Kidnappers Slide, on the upper continental slope of the convergent margin off eastern North Island, New Zealand, has been re-examined using a grid of high-resolution seismic reflection profiles. The slide is not a single feature but a complex of sheet slides and rotational failures ranging from 20 to 140 m thick, and covering a total area of 720 km2. Failures occurred in several phases, on slopes of 1–5°, in late Quaternary, muddy, shelf-edge clinoforms that have prograded into an accretionary, trench-slope basin. Piston cores and seismic stratigraphy show that the main failure probably occurred in early Holocene times but that movements ranged from mid last glacial to late Holocene times.The sheet slides exhibit tensional collapse via numerous listric normal faults that sole out on glide planes; there is no clear evidence of compressional structures anywhere within the complex. The glide planes occur at progressively deeper stratigraphic levels towards the northeastern end of the complex, and near the steep slope that defines the seaward edge of the trench-slope basin. There is retrogressive failure at the top of the slope. The surficial slides are being deformed by growth of active tectonic faults and folds associated with the convergent plate margin.This type of slope failure may be partially related to metastable sandy layers within the last glacial age progradational sequence, and possibly to formation of bubble phase gas at shallow depths. Failure was probably triggered by earthquake loading of sediments in this highly seismic region.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1111/j.1365-3091.1991.tb01257.x

Permalink

	Location	Call Number	Limitation	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

Electronic Resource

From oblique subduction to intra-continental transpression: Structures of the southern Kermadec-Hikurangi margin from multibeam bathymetry, side-scan sonar and seismic reflection (1996)

Collot, Jean-Yves ; Delteil, Jean ; Lewis, Keith B. ; [et al.]

Springer

Marine geophysical researches 18 (1996), S. 357-381

add to mindlist on the mindlist

Details

ISSN: 1573-0581

Keywords: Oblique subduction ; strike-slip faults ; transpressive deformation ; tectonic erosion ; tectonic accretion ; seamount collision ; multibeam bathymetry

Source: Springer Online Journal Archives 1860-2000

Topics: Geosciences , Physics

Notes: Abstract The southern Kermadec-Hikurangi convergent margin, east of New Zealand, accommodates the oblique subduction of the oceanic Hikurangi Plateau at rates of 4–5 cm/yr. Swath bathymetry and sidescan data, together with seismic reflection and geopotential data obtained during the GEODYNZ-SUD cruise, showed major changes in tectonic style along the margin. The changes reflect the size and abundance of seamounts on the subducting plateau, the presence and thickness of trench-fill turbidites, and the change to increasing obliquity and intracontinental transpression towards the south. In this paper, we provide evidence that faulting with a significant strike-slip component is widespread along the entire 1000 km margin. Subduction of the northeastern scrap of the Hikurangi Plateau is marked by an offset in the Kermadec Trench and adjacent margin, and by a major NW-trending tear fault in the scarp. To the south, the southern Kermadec Trench is devoid of turbidite fill and the adjacent margin is characterized by an up to 1200 m high scarp that locally separates apparent clockwise rotated blocks on the upper slope from strike-slip faults and mass wasting on the lower slope. The northern Hikurangi Trough has at least 1 km of trench-fill but its adjacent margin is characterized by tectonic erosion. The toe of the margin is indented by 10–25 km for more than 200 km, and this is inferred to be the result of repeated impacts of the large seamounts that are abundant on the northern Hikurangi Plateau. The two most recent impacts have left major indentations in the margin. The central Hikurangi margin is characterized by development of a wide accretionary wedge on the lower slope, and by transpression of presubduction passive margin sediments on the upper slope. Shortening across the wedge together with a component of strike-slip motion on the upper slope supports an interpretation of some strain partitioning. The southern Hikurangi margin is a narrow, mainly compressive belt along a very oblique, apparently locked subduction zone.