학술논문

The anatomy of long-term warming since 15 ka in New Zealand based on net glacier snowline rise
Document Type
Academic Journal
Source
Geology (Boulder). 41(8):887-890
Subject
24|Quaternary geology
03|Geochronology
alkaline earth metals
Australasia
Be-10
Ben Ohau Range
beryllium
Canterbury New Zealand
Cenozoic
climate change
deglaciation
digital simulation
exposure age
glaciers
global change
global warming
Holocene
isotopes
metals
moraines
New Zealand
numerical models
paleoclimatology
Pleistocene
Quaternary
radioactive isotopes
reconstruction
relative age
South Island
upper Pleistocene
Language
English
ISSN
0091-7613
Abstract
The timing and magnitude of postglacial climatic changes around the globe provide insights into the underlying drivers of natural climate change. Using geomorphologic mapping of moraines, 10Be surface-exposure dating, snowline reconstructions, and numerical modeling, we quantified glacier behavior during Late Glacial (15-11.5 ka) and Holocene (the past ∼11.5 k.y.) time in the Ben Ohau Range, New Zealand. Glaciers were more extensive during the Antarctic Cold Reversal (ACR), than subsequently, and the margins underwent a punctuated net withdrawal over the Holocene. Numerical modeling experiments that achieve the best fit to the moraines suggest that air temperature during the ACR was between 1.8°C and 2.6°C cooler than today, with similar (±20%) prescribed precipitation. After the ACR, a net snowline rise of ∼100 m through the Younger Dryas stadial (12.9-11.7 ka) was succeeded by a further "long-term," or net, rise of ∼100 m between ∼11 k.y. and ∼500 yr ago. Glacier snowline records in New Zealand show generally coherent Late Glacial and Holocene climate trends. However, the paleoclimate record in the southwest Pacific region shows important differences from that in the Northern Hemisphere.