Abstract：

In this talk I will present direct observations of carbon dioxide (CO₂) concentrations in ice cores drilled in Allan Hills Blue Ice Areas, East Antarctica. Based on the isotopic composition of argon in the trapped air, ice as old as 2 million years (Ma) was identified, with a single unreplicated sample dating back to 2.7±0.3 Ma. The oldest pristine CO₂ samples date back to 1.5 Ma and range between 217 to 256 ppm. The similarity between the Early- and Late-Pleistocene interglacial CO₂ argues against the notion that a long-term decline in atmospheric CO₂ initiated the 100 kyr glacial cycles. Older CO₂ samples are affected by the in situ production of CO₂ due to respiration. Additionally, Allan Hills blue ice provides a prime record of atmospheric oxygen. Our results show a surprising lack of variability from 1.5 to 0.95 Ma; even during the past ~0.9 Ma, when the rate of decline was very slow.

Bio：

颜余真，美国莱斯大学地球科学系博士后。2019年博士毕业于普林斯顿大学地球科学系（导师Michael Bender/John Higgins）。研究方向为古气候和同位素地球化学，主要手段为冰芯包裹气体的元素和同位素组成分析。于2014-15年参与了东南极地区Allan Hills蓝冰区为期十周的科学考察，所发现的270万年冰芯入选《科学》杂志2017年十大科学突破之一。

Conference ID (For ZOOM)：1855016889

Suihui (随会) link: https://private.suimeeting.com/share/j/1855016889