Earth Magazine quote about the formation conditions of Hadean zircon.
American Mineralogist: Journal of Earth and Planetary Science noted paper.
"On page 1348 of this issue, Harrison and Wielicki examine 4.4 Ga zircons that appear to have formed from nearly water-saturated conditions, at low temperatures of ca. 680C. But they also show that Tertiary age granites in the Himalaya, formed by under-thrusting of the Indian plate beneath Asia, yield similar temperatures (ca. 660C). Moreover, these granites share more than a thermal history – both the ancient and more recently formed zircons contain inclusions that yield similar pressures, or 5-15 kbar. Two aspects of these results are remarkable, and highly significant; the first is that if nothing else, the Hadean exhibited, at least locally and for a time, a modern-like continental geotherm, effectively equivalent to a Miocene case (at ca. 25C/km). Second, to the extent that P-T conditions are indicative, a similar tectonic setting for both systems is implied; and if the association holds, then active plate tectonics – including subduction – occurred from almost the inception of Earth’s history."
Links to media coverage of Goldschmidt 2014 presentation about a new age of the Popigai impact structure, Russia and the possible association to the Eocene-Oligocene mass extinction event.