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DEPARTMENT OF PHYSICS, APPLIED PHYSICS AND ASTRONOMY Department of Physics, Applied Physics & Astronomy Colloquium March 11, 2015 CII 3051, 4:00PM - 5:00PM Host: Professor Toh-Ming Lu Professor Bruce Watson Department of Earth & Environmental Sciences Rensselaer Polytechnic Institute “The Environment of Earliest Earth: Decoding the Oldest Crystals” Abstract: The first 700 million years of Earth’s existence (the Hadean Eon) are widely regarded as the most geodynamically vigorous period in the history of our planet. It has been variously inferred that during this time the Earth: 1) collided with a Mars-sized-object; 2) formed a deep magma ocean; 3) grew the first continents; 4) suffered withering bombardment; and 5) witnessed the emergence of life. In terms of ‘hard’ geochemical evidence, however, the record from these earliest times is limited, and our understanding of Hadean events is rudimentary at best. The oldest firmly dated terrestrial rock is only 4.06 billion years (Gyr) old, so there is no rock record to inform us about processes that occurred during the prior 500 Myr of Earth history. Prof. Watson will provide a summary of the evidence gleaned over the past ten years -- much of it at RPI -- from 4+ Gyr-old zirconium silicate crystals (zircons) from Western Australia supporting the view that continental crust was already fully developed, that the gases emanating from ancient volcanoes into the Hadean atmosphere were much like those of today, and liquid water was present at or near the Earth’s surface. NOTE: The complete list of colloquia and seminars is posted on the department web site, http://www.rpi.edu/dept/phys/calendar.html and also on the Institute Calendar of Events, http://events.rpi.edu/main/showMain.rdo;jsessionid=8589F4957B89E6751705AC48D37C96A4. Return to Top