کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4678251 | 1634844 | 2010 | 9 صفحه PDF | دانلود رایگان |
Marine Isotope Stage 19 (MIS 19) is the oldest interglacial period archived in the EPICA Dome C ice core (~ 780 ky BP) and the closest “orbital analogue” to the Holocene — albeit with a different obliquity amplitude and phase with precession. New detailed deuterium measurements have been conducted with a depth resolution of 11 cm (corresponding time resolution of ~ 130 years). They confirm our earlier low resolution profile (55 cm), showing a relatively smooth shape over the MIS 20 to MIS 18 time period with a lack of sub-millennial climate variability, first thought to be due to this low resolution. The MIS 19 high resolution profile actually reveals a strong isotopic diffusion process leading to a diffusion length of at least ~ 40 cm erasing sub-millennial climate variability. We suggest that this diffusion is caused by water-veins associated with large ice crystals at temperatures above −10 °C, temperature conditions in which the MIS 19 ice has spent more than 200 ky. This result has implications for the selection of the future “oldest ice” drilling site.
Journal: Earth and Planetary Science Letters - Volume 298, Issues 1–2, 15 September 2010, Pages 95–103