Lear combines oxygen isotope analysis with investigations into the amount of magnesium that takes place of the calcium in microfossils.
[7] In 2016 Lear investigated the reasons that ice ages now take place every 100,000 years, rather than on the 40,000 intervals that they occurred on previously.
[8] By monitoring the chemical composition of microfossils, Lear identified that there was more carbon dioxide stored in the deep oceans during the ice ages at 100,000 year intervals.
[8] She showed that volcanic eruptions of the Columbia River Basalt Group releases carbon dioxide into the atmosphere, triggering a decline in ocean pH and increasing global temperatures.
[9] The associated sea level rise buried large numbers of marine organisms in sediment, transferring volcanic carbon to the ocean over thousands of years.