Nov
16
November Café Scientifique with Mark Jellinek
Posted by: jdewitt | November 16, 2015 | Leave a Comment
Dear Café Scientifiquers, our next café will happen on Tuesday November 24th, 7:30pm at The Railway Club. Our speaker for the evening will be Dr. Mark Jellinek. The title of his talk is:
The Formation and Breakup of Earth’s Supercontinents and the Remarkable Link to Earth’s Climate and the Rise of Complex Life
Earth history is marked by the intermittent formation and breakup of “supercontinents”, where all the land mass is organized much like a completed jigsaw puzzle centered at the equator or pole of the planet. Such events disrupt the mantle convective motions that cool our planet, affecting the volcanic and weathering processes that maintain Earth’s remarkably hospitable climate, in turn. In this talk I will explore how the last two supercontinental cycles impelled Earth into profoundly different climate extremes: a ~150 million year long cold period involving protracted global glaciations beginning about 800 million years ago and a ~100 million year long period of extreme warming beginning about 170 million years ago. One of the most provocative features of the last period of global glaciation is the rapid emergence of complex, multicellular animals about 650 million years ago. Why global glaciation might stimulate such an evolutionary bifurcation is, however, unclear. Predictable environmental stresses related to effects of the formation and breakup of the suprecontinent Rodinia on ocean chemistry and Earth’s surface climate may play a crucial and unexpected role that I will discuss.