کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6427225 | 1634701 | 2016 | 10 صفحه PDF | دانلود رایگان |

- Changes in leaf physiology, δ13C and δD are recorded from a â¼100 kyr terrestrial sequence at the O/M boundary in southern New Zealand.
- Record indicates an abrupt ecosystem physiological change at the Mi-1 termination.
- Indicative of a sharp increase in atmospheric pCO2 as well as local precipitation.
- CO2 increase contemporaneous to the onset of the Antarctic Ice Sheet deterioration.
A rise in atmospheric CO2 is believed to be necessary for the termination of large-scale glaciations. Although the Antarctic Ice Sheet is estimated to have melted from â¼125% to â¼50% its modern size, there is thus far no evidence for an increase in atmospheric CO2 associated with the Mi-1 glacial termination in the earliest Miocene. Here, we present evidence from a high-resolution terrestrial record of leaf physiological change in southern New Zealand for an abrupt increase in atmospheric CO2 coincident with the termination of the Mi-1 glaciation and lasting approximately 20 kyr. Quantitative pCO2 estimates, made using a leaf gas exchange model, suggest that atmospheric CO2 levels may have doubled during this period, from 516±111ppm to 1144±410ppm, and subsequently returned back to 425±53ppm. The 20-kyr interval with high pCO2 estimates is also associated with a period of increased moisture supply to southern New Zealand, inferred from carbon and hydrogen isotopes of terrestrial leaf waxes. The results provide the first high-resolution record of terrestrial environmental change at the Oligocene/Miocene boundary, document a â¼20 kyr interval of elevated pCO2 and increased local moisture availability, and provide insight into ecosystem response to a major orbitally driven climatic transition.
Journal: Earth and Planetary Science Letters - Volume 455, 1 December 2016, Pages 115-124