Further information about CLIMES may be obtained
from Associate
Professor David J. Lowe <d.lowe (at) waikato.ac.nz>.
Studies of how climates and environments have changed are dictated by time scale: very long-term change is measured in millions of years, long-term change in hundreds or tens of millennia, short-term change in millennia, and very short-term change in centuries or decades. Studies of environmental change over the last 2.5 million years are usually referred to as Quaternary science. Documentation and analysis of modern environments and processes typically span a few years or decades. Research at Waikato University and especially within the Department of Earth Sciences covers all these timescales and is wide-ranging, dealing with both marine and terrestrial deposits of many different kinds. Marine studies are based on the analysis of sediments in deep-sea cores, and terrestrial studies include research on long sedimentary sequences, loess deposits, pyroclastic and volcanic deposits including tephrochronology, lake and peat deposits, cave deposits, glacial materials, and paleosols.
Major advances in understanding have arisen also
from analyses of long ice cores from Greenland and Antarctica
and elsewhere, and from tree-ring studies (dendroclimatology and
dendrochronology). Ice cores, tree rings and laminated lake or
marine sediments provide high-resolution archives of the past
on an annual or near-annual basis. The major focus of much of
this work has been to reconstruct paleoenvironments and palaeoclimates
using a variety of proxy tools including pollen analysis and other
methods.
Such studies have involved shorter time scales
and higher sampling resolution and an increasing emphasis on quantifying
palaeoclimatic parameters and feedback processes for short-lived
‘abrupt’ climatic change events that lasted around 1000 years
or less (popularised by the melodramatic Hollywood film The
Day After Tomorrow). One recent project in which Waikato staff
have developed leading roles is NZ-INTIMATE (INTegration of Ice-core,
Marine And TerrEstrial records) that is developing an integrated
high-resolution record of climatic change events in the New Zealand region for the past 30,000 years (see www.paleoclimate.org.nz).
Climate Change Discussion Group (CCDG)
A climate change discussion group meets monthly in the School
of Science and Engineering. For further information contact
Tom Whittaker (Ph.D. Candidate and Comer Fellow, Departments
of Chemistry and Earth & Ocean Sciences), email: tew3(at)waikato.ac.nz
All this research is underpinned by the
application of radiometric and other dating techniques including
radiocarbon (see below), K-Ar, Ar-Ar, fission-track and palaeomagnetic
methods, dendrochronology, ice core and varved lake sediment
dating, and by the use of widespread tephra (volcanic ash) layers
as isochronous time planes to link and date sequences in different
environments. Recent research has involved developing new techniques
to detect and analyse ‘cryptic’ or ‘hidden’ tephra
deposits, which are typically microscopic ash deposits usually
found disseminated within peats or lake sediments. A new
(U-Th)/He dating system has recently been constructed in the
Department of Earth Sciences, one of only a handful of such systems
in the world.
Pastoral volcanic landscape near Mt Tarawera, North Island.
Photo: David Lowe
New Zealand, by virtue of its remote location,
is unique as a substantial, oceanic mid-latitudinal landmass
that has remained untouched by human activities until the
last millennium. However, since the time of first settlement
by Polynesians around 1250–1300 AD, and subsequently by
Europeans, severe modification of much of the New Zealand
landscape has taken place at rates possibly without parallel
anywhere else in the world. Research documenting these environmental
changes, together with studies on archaeological sites, are
carried out by researchers within the environmental change
group. Considerable research has also been undertaken on
coastal processes and how these relate to very short-term
climate change. As well, work has also begun in Antarctica where
soil permafrost is being monitored to detect the rate and extent
of permafrost change. Environmental and soil-related problems
relating to different land uses over the past few decades
are also being targeted.
A review paper dealing with the Quaternary history
of New Zealand was published in 1999 and is available here
(PDF file, 2.5 MB) (Newnham, R.M.; Lowe, D.J.; Williams,
P.W. 1999. Quaternary environmental change in New Zealand: a
review. Progress in Physical Geography 23, 567-610). http://www.ingentaconnect.com/content/arn/pipg/1999/00000023/00000004/art00006
Almost all the research activities within CLIMES are collaborative; all academic staff members and postgraduate students work directly with colleagues from both national and international agencies or research institutions including regional councils, various CRIs, and universities. Joint work is undertaken with the International Global Change Institute, esentially a climate-change group comprising geographers and social scientists housed in the Faculty of Arts and Social Sciences, and with specialists in geographic information system (GIS) specialists within the Geography Department of FASS.
Tephrochronologists and paleoclimate specialists examine an ice wedge (“permafrost”) overlain by white tephra layer (Dawson tephra) aged ca. 24,000 cal. yr BP, Yukon Territory, Canada.
Photo: David Lowe
- Identifying a late-glacial (13,600-12,600 cal
yr BP) climatic cooling episode in New Zealand using
high-resolution, tephra-dated pollen sequences, Urewera National
Park
- Testing the synchroneity of pollen signals using
tephrostratigraphy
- Identifying abrupt changes in climate (century-decadal
scale) over the past 10,000 yrs from palaeolimnological
study of a meromictic lake in British Columbia
- Assessing the impacts and hazards of tephra fallout
in northern North Island
- Dating archaeological and palynological sites
using radiocarbon, tephrochronology and 'wiggle-match'
dating to determine the timing of earliest Polynesian settlement
in New Zealand
- Studies on New Zealand's palaeoclimate from AD
950-1950 using radiocarbon measurements and dendrochronology
- Glacial history of the Southern Alps (West Coast,
South Island)
- Sequence cyclostratigraphy and astronomical forcing
(Milankovitch cycles), Wanganui Basin
- Reconstructing palaeoenvironments from Quaternary
tephra and loess deposits, and associated paleosols,
in central and western North Island
- Mapping volcanic, pyroclastic and other deposits
in northern Taupo Volcanic Zone and associated paleosols
- Antarctic research (Dry Valleys region) including
studies of glacial history.
- Developing an integrated climate event stratigraphy
for the New Zealand region over 30,000 years as part
of the NZ-INTIMATE project
- Glacial record for South Island using stratigraphy,
palynology, tephrochronology, and 14 C, OSL and exposure-age
dating
- Identifying and dating climatic change since 30,000
years ago from high-resolution ocean cores
- Patterns of climate change since MOIS 5e in North
Island via lakes and bogs using palynology, peat morphology
and tephrochonology
- Radiocarbon calibration and palaeoclimate during Oxygen
Isotope Stage 3 using kauri ( Agathis australis )
- Chronology and pattern of Polynesian settlement in
New Zealand
- Testing new radiocarbon dating materials and applications
using tephrochronology
- Contributing to "Encyclopaedia of Quaternary Science" (to
be published by Elsevier)
- Reconstructing cryptotephrostratigraphic records spanning
5000 years, Kopouatai bog
Staff
Associate Professor David J. Lowe
Dr Penny Cooke (Comer Postdoctoral
Research fellow)
Associate Professor Chris Hendy (Chemistry)
Dr Willem de Lange
Professor Peter Kamp
Professor Cam Nelson
Doctoral projects
- Dr Joanna L. Horrocks "Stratigraphy, chronology and correlation
of the Plio-Pleistocene (c. 2.2-0.8 Ma) Kauroa Ash sequence,
western central North Island" (2001)
- Dr Penny J. Cooke "Aspects of Neogene palaeoceanography in the
southern Tasman Sea (DSDP site 593)" (2002)
Masterate projects
- Bruce G. Murdoch "Holocene evolution of Ohope barrier spit,
eastern Bay of Plenty, North Island, New Zealand" (2005)
- Jeremy Cole-Baker "Sedimentology and tephrochronology of
Late Glacial and Holocene peat and lake sediments, south
Westland, South Island, N.Z." ()
Doctoral project
- Will Esler "Palaeoenvironmental change and volcanic
history of the Rotorua Basin since c. 220,000 years ago"
- Tom Whittaker "Abrupt climate change during Last
Glaciation using speleothem analysis"
Masterate project
- Lisa Pearson "Geochemistry of sediments in cores from
Lake Rotorua"
Publications
See publication lists for staff members
To visit the International Union for Quaternary Research (INQUA)
home page, go to http://inqua.nlh.no/
Professor Rewi Newnham (University of Plymouth, U.K.), who
is undertaking research with staff in Earth Sciences, examines
a peat section near Hamilton in which a white volcanic ash
layer, erupted from Taupo caldera volcano, is visible. Photo :
Maria Gehrels
Archaeological excavation of an early Maori village on dunes
at Papamoa, North Island, New Zealand, showing white Kaharoa
Tephra forming the ‘floor' of the excavation. The Kaharoa
layer has been dated at 1314 AD ± 12 by ‘wiggle-match' dating
at Waikato University and provides a benchmark for earliest
Polynesian settlement in North Island. Photo : David
Lowe
The Waikato Radiocarbon Dating Laboratory
(housed within the School of Science and Technology)
is one of the foremost radiocarbon laboratories in the world.
It provides Quantulus liquid scintillation spectrometry and
accesses AMS faciltities with its purpose-built graphite line.
It has a strong research record including provision of one
of the international radiocarbon standards, the design and
manufacture of an international scintillation counting vial,
the generation of a Southern Hemisphere calibration curve
for the last 1000 years in a joint project with The Queen’s
University of Belfast, improving the accuracy of ‘old’ radiocarbon
dates by developing new background standards and protocols,
and high-precision dating faciltities for applications
world-wide including for geoscientific research and archaeology.
In 2003 the lab’s director Dr Alan Hogg, together with
Associate Professors David Lowe and John Ogden and Dr Jonathan
Palmer, were awarded a Marsden Fund award for a project
entitled “Radiocarbon calibration and palaeoclimate during
Oxygen Isotop Stage3: testing hypotheses of abrupt climate
change using New Zealand kauri (Agathis australis).” In
2005 Dr Fiona Petchey and colleagues were awarded a Marsden
Fun award for a project involving dating marine shell:
“The last migration: improving the shell chronology”.
Staff:
Dr Alan Hogg (Director)
Dr Fiona Petchey (Deputy Director)
To
visit the laboratory’s award-winning home page, go to:
http://radiocarbondating.com/.
|
