Among the 1,107 meters of sediments recovered and analyzed for microfossil content, a two-meter thick layer in the core displayed extremely rich fossil content. This is unusual because the Antarctic ice sheet was formed about 35 million years ago, and the frigid temperatures there impede the presence of woody plants and blooms of dinoflagellate algae.
"We all analyzed the new samples and saw a 2,000 fold increase in two species of fossil dinoflagellate cysts, a five-fold increase in freshwater algae and up to an 80-fold increase in terrestrial pollen," said Warny. "Together, these shifts in the microfossil assemblages represent a relatively short period of time during which Antarctica became abruptly much warmer."
These palynomorphs, a term used to described dust-size organic material such as pollen, spores and cysts of dinoflagellates and other algae, provide hard evidence that Antarctica underwent a brief but rapid period of warming about 15 million years before present.
"This event will lead to a better understanding of global connections and climate forcing, in other words, it will provide a better understanding of how external factors imposed fluctuations in Earth's climate system," said Harwood. "The Mid-Miocene Climate Optimum has long been recognized in global proxy records outside of the Antarctic region. Direct information from a setting proximal to the dynamic Antarctic ice sheets responsible for driving many of these changes is vital to the correct calibration and interpretation of these proxy records."
These startling results will offer new insight into Antarctica's climatic past insights that could potentially help climate scient
|Contact: Ashley Berthelot|
Louisiana State University