Abstract
Here we use δ18O ratios measured in tree rings of crossdated sub-fossil wood to reconstruct an annually resolved record of temperature and δ18O of meteoric water for an interglacial late Pliocene-early Pleistocene fossil forest found on Bylot Island, Nunavut, Canada. Our record represents the first crossdated record of Pliocene wood. Mean annual temperatures determined in this study average -3.4±3.8°C, which is 11.4±4.4°C warmer than present-day Bylot Island (-14.8±2.2°C). June-July temperatures average 13.5±1.1°C, approximately 12.6±1.6°C warmer than present-day. Meteoric water δ18O values average -15.5±2.9‰, ~2-6‰ more enriched than present values of precipitation δ18O. Our temperatures are comparable to mid-Pliocene modeled temperatures for the Arctic (3-5°C warmer than present), suggesting that interglacial warm periods in the late Pliocene-early Pleistocene may have been as warm as the mid-Pliocene warm period. That both the Bylot Island forest deposit and the Kap København deposit represent the remains of northern tree-line vegetation that lived during warm interglacial periods within the overall cool Plio-Pleistocene suggests that forest deposits in the Arctic capture a snapshot of interglacial conditions during the Plio-Pleistocene rather than the average Pliocene climate and may not be suitable records to study Pliocene cooling.
Original language | English (US) |
---|---|
Pages (from-to) | 313-322 |
Number of pages | 10 |
Journal | Palaeogeography, Palaeoclimatology, Palaeoecology |
Volume | 369 |
DOIs | |
State | Published - Jan 1 2013 |
Keywords
- Arctic
- Pliocene climate
- Stable isotopes
- Temperature
- Tree rings
ASJC Scopus subject areas
- Oceanography
- Ecology, Evolution, Behavior and Systematics
- Earth-Surface Processes
- Palaeontology