Investigation of late-Holocene moraines in the western Southern Alps, New Zealand, applying Schmidt-hammer exposure-age dating

Abstract

Chronological studies applying Schmidt-hammer exposure-age dating (SHD) were performed on six glacier forelands in the western part of the Southern Alps, New Zealand. Although lithological heterogeneity prevented a regional age-calibration curve to be established, local age-calibration curves for La Perouse Glacier and Strauchon Glacier could be derived. They show similar linear equations and trends/slopes and enabled a preliminary assessment of the representativeness of individual 10Be terrestrial cosmogenic nuclide dating (TCND)-ages obtained from the other forelands. No mid- and early-Holocene advance periods were detected. Clusters of moraine ages date around 2800, 1850–1450, and 1100–900 years ago, followed by the ‘Little Ice Age’ commencing c. 500 years ago. There is no good agreement with earlier radiocarbon-based studies and recently published TCND-chronologies. As it will be outlined, this partly could be the result of different approaches to the palaeoclimatic interpretation of the dated samples. The results obtained from this recent study do not support an elsewhere proposed general asynchronous glacier behaviour between the mid-latitudinal Northern and Southern hemispheres.