| Summary: | Holocene glacial moraines in Mt Cook National Park are re-dated by multi-parameter dating techniques. The deposits from six main valley glaciers were examined. In earlier studies by other workers the glacial moraine chronology of three of these valleys had been specified using radiocarbon, historical and lichen dating. Results from the present study are compared with this earlier work. A chronology of glacial events is here defined using
historical, radiocarbon and rock weathering rind thickness
dating. In addition, post-depositional surface modifications
are described using changes in plant development, lichen
growth and soil properties.
The more precise dating methods delineate up to
fifteen separate glacial expansion phases during the last
10 000 years. The weathering rind chronology defines glacial
events around 7200,4200,3790,3350,2940,2540,2160,1830,1490,
1150,840,580,340,135 and <100 years ago. The chronology is
strongly correlated with the radiocarbon dated glacial
sequence; 8000, c.7000, 4200-4000, 3400, 2800, 2500, 2200-
2100, 1800-1600, 1100-1000, 800-700, 340 and 250 yr B.P.
In recent historical times the glacial record is characterised
by a number of local,minor advances prior to 1900, followed
by a general still-stand until about 1930-40. During the
last forty years all of the glaciers have been retreating.
The widespread glacier recession supports evidence of a
climatic warming in New Zealand since about 1930 which
has intensified in the last thirty years.
The Mt Cook glacial moraine chronology shows good
agreement with the Holocene glacial record described from
elsewhere in the Southern Alps of the South Island, New
Zealand. A brief comparison with events associated with
cool climate periods from elsewhere in the Southern Hemisphere
demonstrates a similarity with events in South America, New
Guinea, Australia and Antarctica.
The present study indicates the need for revision of the
original Mt Cook glacial moraine chronology which had implied
extensive glacial expansion around the 17th century and
which had grouped all of the events listed above as having
formed in the last 1000 years.
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