Surface exposure ages from Hjorth Hill, McMurdo Sound, Antarctica

The samples were collected by M.D. Kurz and R. Ackert and colleagues during the 1990 and 1992 field seasons. The samples are archived at Woods Hole Oceanographic Institution. The ages, provided below in the table, provide age constraints on this important record of past fluctuations of the West Antarctic Ice Sheet.

Surface exposure ages from Hjorth Hill --------------------------------------------3He 10Be Sample moraine Lithology mineral alt (m) Age (+-1 sig) Age (+-1 sig) ...........................................(kyrs) (kyrs) GP92-641-2 RS1r basalt olivine 300 40.0 0.8 KBA89-140 RS2 basalt olivine 310 56.7 1.8 KBA89-142 RS2 basalt olivine 310 83.3 2.7 KBA89-143 RS2 granite quartz 310 28.4 0.7 38.1 2.7 KBA89-148 RS2 quartzitequartz 310 47.9 0.6 48.2 0.7 DK92-477-3 W3 basalt olivine 365 21.4 0.8 DK92-477-4-1 W3 basalt cpx 365 40.6 1.2 DK92-477-4-2 W3 basalt cpx 365 29.3 1.7 3He ages calculated using production rate of 121 and 133 at/g/yr (sealevel, high lat) for olivine and quartz respectively. 10Be ages calculated using production rate of 5.1 at/g/yr RS1r=Ross Sea Drift recessional moraine S2= older Ross Sea Drift W3= Wilson-Piedmont drift