50thKaikoura05 -1- Kaikoura 2005 CHARACTERISATION OF NEW ...

This paper explores what we know of New
Zealand’s fossil freshwater fishes, and seeks to
place them in the context of the extant fauna (based
largely on material collected in the last few years
by a student from the Geology Department,
University of Auckland; Liz Kennedy of GNS,
Lower Hutt; and Daphne Lee and Jon Lindqvist,
Geology Department, Otago University.)
In the more distant past WRB Oliver mentioned
eleotrids from the Pliocene (now known to be mid-
Pleistocene) of the Ormond Valley, inland from
Gisborne, and also some galaxiids from near
Dunedin; Gerald Stokell added galaxiids from near
Middlemarch, and I reported on all of these and
provided a summary some 30 years ago.
Things have moved rapidly in the past year or so,
and we can now report on:
1. A couple of scales from an undetermined lower
perciform family from an Early Miocene
deposit near Bannockburn;
2. The first fossil record of grayling
(Prototroctes) from the mid-Pleistocene of the
Ormond Valley, as well as:
3. Additional eleotrids of the genus
Gobiomorphus from the Ormond Valley;
4. An additional eleotrid from Early Miocene
deposits near St Bathans; and
5. A series of Early Miocene galaxiid fossils from
diatomite deposits near Middlemarch.
There are also numerous fish otoliths in Geology
Department, University of Otago collections that
have not yet been looked at seriously, and which
have potential to provide new revelations.
I will seek to clarify the significance of these fossils
in the evolutionary history of the fauna.
ORAL
A PRELIMINARY SEDIMENTATION
MODEL FOR BENEATH THE MCMURDO
ICE SHELF
R. McKay 1 ,P. Barrett 1 , G. Dunbar 1 ,T.Naish 1 ,
M. Harper 2 &L.Carter 1
1 Antarctic Research Centre, Victoria University of
Wellington, PO Box 500 Wellington
2 School of Earth Sciences, Victoria University of
Wellington, PO Box 500, Wellington
(robert.mckay*vuw.ac.nz)
Ross Island has been depressing the crust under its
own weight for at least the last million years, and at
the same time has been acting as the western
pinning point for the Ross Ice Shelf. As a result, a
thick sedimentary sequence has accumulated in a
sea floor depression now 900 m deep beneath the
McMurdo-Ross Ice Shelf on the south side of Ross
Island in Windless Bight. These sediments record
the history of ocean currents and the ice shelf itself
to be investigated as part of the ANDRILL project
(http://www.andrill.org/).
Here we present results of two 60-cm-long gravity
cores taken from the sea floor beneath the ice shelf
in January 2003, and which record recent
sedimentation there. Core 1 was taken 5km east of
the ice shelf front, and contains a record of the past
~20,000 years. The basal unit is a diamict that
contains clasts, some subrounded and striated, and
derived from Transantarctic Mountains. This is
interpreted as representing basal debris from an
expanded Ross Ice Shelf/Sheet at the LGM. This
passes upwards into a well-sorted sand layer, which
represents locally derived sediment either deposited
through a retreating ice shelf or beneath the ice
shelf as a result of slope instability. Overlying the
sand is a series of fine muds and muddy sands,
which are indicative of sub-ice shelf conditions,
with only minor fluctuations of the ice shelf front.
The biogenic content also suggests that the Ross Ice
Shelf front has not retreated significantly from its
present position during the Holocene and that
seasonally open water has been present in
McMurdo Sound for much of this period.
Core 2, taken 12 km east of the ice shelf front,
contains a record of the past ~10,000 years. It
consists mainly of locally derived sandy mud, and
contains a higher biogenic component of diatoms
and sponge spicules, typically more than 20%. The
uniform nature of this core suggests that current
flow has varied little from the present regime (5-20
cm/sec; Robinson, 2005), and also supports the
view that the ice shelf front has varied little during
the Holocene.
Additional cores are planned for 2005/06 field
season and will be used to develop a high resolution
sedimentation model in preparation for deep
drilling planned by ANDRILL for the 2006/07
season.
ORAL
LATE QUATERNARY
PALEOEARTHQUAKES ON THE
NORTHERN NORTH ISLAND FAULT
SYSTEM, NEW ZEALAND
V. Mouslopoulou 1,2 ,A.Nicol 2 , T. Little 1 ,
D. Beetham 2 , K. Berryman 2 ,R. Langridge 2 ,
P. Villamor 2 &S.Beanland 1,2†
1 Victoria University of Wellington, School of
Earth Sciences, PO Box 600, Wellington.
2 Institute of Geological and Nuclear Sciences, PO
Box 30 368, Lower Hutt.
(V.Mouslopoulou*gns.cri.nz)
† Deceased
50 th Kaikoura05 -55- Kaikoura 2005