50thKaikoura05 -1- Kaikoura 2005 CHARACTERISATION OF NEW ...
50thKaikoura05 -1- Kaikoura 2005 CHARACTERISATION OF NEW ...
50thKaikoura05 -1- Kaikoura 2005 CHARACTERISATION OF NEW ...
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spore-pollen catalogue<br />
[http://data.gns.cri.nz/sporepollen]. Our aim is to<br />
integrate these with the NPC and FRED databases<br />
to provide a single "seamless" system.<br />
ORAL<br />
QMAP KAIKOURA: THE <strong>NEW</strong> 1:250 000<br />
GEOLOGICAL MAP <strong>OF</strong> NORTHEASTERN<br />
SOUTH ISLAND<br />
M.S. Rattenbury 1 ,D.B.Townsend 1<br />
& M.R. Johnston 2<br />
1 GNS Science, PO Box 30368, Lower Hutt<br />
2 395 Trafalgar St, Nelson, New Zealand 7001<br />
(m.rattenbury*gns.cri.nz)<br />
A pre-publication version of the new 1:250 000<br />
geological map of the <strong>Kaikoura</strong> region is presented.<br />
The map covers 18 100 km 2 of northeastern South<br />
Island, from northern Canterbury to southern<br />
Marlborough, including <strong>Kaikoura</strong> and parts of<br />
Buller and Nelson. The region straddles the<br />
Australia-Pacific plate boundary and the prominent<br />
Marlborough Fault System, incorporating the<br />
Alpine, Awatere, Clarence, and Hope faults<br />
amongst others, is a feature of the area. The map<br />
significantly refines the location of many of the<br />
known active faults and many new traces have been<br />
identified.<br />
The basement rocks include parts of most New<br />
Zealand tectonostratigraphic terranes. North of the<br />
Alpine Fault the Buller and Takaka terranes occur<br />
in the far northwest of the map and are intruded by<br />
the granitic Karamea and Rahu suites. The Median<br />
Batholith to the east includes the mafic Rotoroa<br />
Complex and the dominantly felsic Tasman<br />
Intrusives and Separation Point Suite granite.<br />
Closer to the Alpine Fault are relatively restricted<br />
outcrops of the Brook Street and Murihiku terranes,<br />
and a wider exposure of the Dun Mountain-Maitai<br />
and Caples terranes. Southeast of the Alpine Fault,<br />
the Torlesse composite terrane dominates the map<br />
sheet area comprising greywacke of Rakaia and<br />
Pahau terranes in the west and east respectively.<br />
The Rakaia rocks of Triassic age are increasingly<br />
metamorphosed towards the west, up to greenschist<br />
facies, textural zone III schist near the fault. The<br />
weakly metamorphosed Late Jurassic-Early<br />
Cretaceous Pahau terrane greywacke is generally<br />
less structurally deformed than the Rakaia terrane<br />
apart from several zones of melange and broken<br />
formation. One of these, the Esk Head belt, occurs<br />
at the western edge of the Pahau terrane and is<br />
structurally discordant to the Rakaia terrane. The<br />
Esk Head belt also contains large areas of poorly<br />
bedded and structurally discontinuous sandstone.<br />
The Late Cretaceous and Tertiary rocks of the<br />
region have been unified under a simplified<br />
stratigraphic schema using existing, established<br />
names. Where space on the map permits, local<br />
stratigraphic detail has been preserved to reflect the<br />
diversity of multiple depositional basins,<br />
particularly for the Late Cretaceous and Miocene<br />
rocks. These rocks are predominantly of marine<br />
origin but locally significant terrestrial and volcanic<br />
rocks occur. Igneous rocks are relatively abundant<br />
in the east of the map area. The most conspicuous<br />
of these is the Tapuaenuku Igneous Complex, a<br />
discrete mafic igneous pluton which intrudes Pahau<br />
terrane and is accompanied by an extensive, largely<br />
radial dike swarm. Time transgressive units such as<br />
the Amuri Limestone are another feature of the<br />
sheet.<br />
Glacial till and associated outwash gravel in<br />
alluvial terraces dominate the widespread<br />
Quaternary deposits of the region. Scree, rock<br />
glacier and alluvial fan deposits are common in the<br />
mountains and raised interglacial beach deposits<br />
adjacent to the coast reflect Late Quaternary uplift.<br />
Many lakes in the region are dammed by landslide<br />
deposits, most of which are attributed to strong<br />
earthquake shaking.<br />
POSTER<br />
SOME LIKE IT HOT! CORE COMPLEX<br />
FORMATION IN THE CENTRAL AEGEAN<br />
SEA, GREECE, AND POSSIBLE<br />
IMPLICATIONS FOR THE PAPAROA CORE<br />
COMPLEX IN BULLER, SOUTH ISLAND,<br />
<strong>NEW</strong> ZEALAND<br />
Uwe Ring 1 , Klaus Gessner 2 , Stephanie Brichau 3<br />
& Johannes Glodny 4<br />
1 Department Geological Sciences, Canterbury<br />
University, Christchurch, New Zealand.<br />
2 School of Earth Sciences, University of Western<br />
Australia, Perth, Australia.<br />
3 Department of Geology, University of Kansas,<br />
Lawrence, KS 66045, USA.<br />
4 GeoForschungsZentrum Potsdam, 14473 Potsdam,<br />
Germany.<br />
(uwe.ring*canterbury.ac.nz)<br />
Continental extension is very differently expressed<br />
and varies from rifting with little extension resolved<br />
on slowly displacing high-angle faults through<br />
core-complex forma-tion, which in extreme cases<br />
may accommodate more than 100 km of<br />
displacement with slip rates >10 km/Myr on the<br />
master fault. Numerical simulations suggest that the<br />
viscosity of the lower crust plays a fundamental<br />
role in the mode of continental exten-sion (Wijns et<br />
al. <strong>2005</strong>). A high viscosity lower crust (and thus a<br />
small viscosity con-trast between the ductile lower<br />
and the brittle upper crust) during extension favours<br />
rift development. A lower strength of the lower<br />
crust, due to a low viscosity, favours a core<br />
complex mode of continental extension. Within the<br />
50 th <strong>Kaikoura</strong>05 -74- <strong>Kaikoura</strong> <strong>2005</strong>