Guest Speaker Dr. Warren Wood, April 24th, 2015
“Origin and Fate of Water on Earth: An Attempt to State the Problem”
Room 204 Natural Science Building
12:30 – 1:30 p.m., Friday, April 24, 2015
The origin of water on Earth is a question from antiquity. We currently know from sediments that surface water has been on Earth since at least 4.2 Ga and mass balance dictates that there are only four scenarios for it origin: 1) Water has been on Earth since it’s origin; 2) Water came externally from outer space (comets and or meteorites) some time after Earth’s origin; 3 Water came internally from within the Earth after it’s origin; 4) Water came from both internal and external sources after Earth’s origin. If the water has been added since the Earth’s origin it may have been either steady state or transient in nature. Few rocks or minerals exist before this time; thus, any narrative is based on speculation informed by models, calculations, and inference from meteorites and planets in our solar system but significant uncertainties will always remain. This seminar will attempt to articulate the current conceptual models and perhaps more importantly, try to state and constrain the problem. Within this framework a new model is propose that is constrained by mass balance and D/H isotopes. The fate of water on Earth is better understood as we have millions of examples of the thermal evolution of main sequence sun-sized stars from which to draw parallels.