There were seven volcanic eruptions in which volcanoes exhaled sulphate aerosol. This eruptions occurred during the mid-Cenozoic Era which took place 34 to 7 million years ago in the Northern high plains of North America. In our days, there's been many volcanic eruptions.
One meteor impact took place at the end of the Cretaceous which came in the time of global warming, which continued during the beginnings of Cenozoic Era.
Tectonic Plates Movements:
During the Cenozoic Era the Atlantic Ocean continued to open and because of the moving of the tectonic plates, the configuration of today's continents were created. This moving or process involved collisions, the creation of the Alps, Andes, Himalayas, and the formation of pacific coast mountains. Great areas of Europe and North America were covered by ice sheets and in this time the formation of high-mountain areas and ice bergs happened during the Pleistocene Epoch.