Publications by authors named "Julie Brigham-Grette"
Broad-scale climate control of vegetation is widely assumed. Vegetation-climate lags are generally thought to have lasted no more than a few centuries. Here our palaeoecological study challenges this concept over glacial-interglacial timescales.
View Article and Find Full Text PDFThe El'gygytgyn impact structure in Chukutka, Arctic Russia, is the only impact crater currently known on Earth that was formed in mostly acid volcanic rocks (mainly of rhyolitic, with some andesitic and dacitic, compositions). In addition, because of its depth, it has provided an excellent sediment trap that records paleoclimatic information for the 3.6 Myr since its formation.
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- Understanding the Arctic climate's evolution from the warm middle Pliocene to early glacial cycles has been challenging due to a lack of detailed historical data.
- Evidence from Lake El'gygytgyn indicates that summer temperatures were about 8°C warmer than today during 3.6 to 3.4 million years ago, with CO2 levels around 400 ppm.
- The findings reveal intense warmth and rapid cooling events during the transition to the Pleistocene, while Arctic summers remained warmer than present until approximately 2.2 million years ago, which corresponded with the start of significant Northern Hemisphere glaciation.
The reliability of Arctic climate predictions is currently hampered by insufficient knowledge of natural climate variability in the past. A sediment core from Lake El'gygytgyn in northeastern (NE) Russia provides a continuous, high-resolution record from the Arctic, spanning the past 2.8 million years.
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