Tectonics Study: Quartz

A thin, polished slice of a rock collected from the Jack Hills of Western Australia, viewed through a special microscope equipped with a gypsum plate that shows the rainbow spectrum of quartz that makes up the rock. Whereas the rocks at the Jack Hills are greater than 99% quartz, the remaining 1% of material includes the precious zircons.

Scientists led by Michael Ackerson, a research geologist at the Smithsonian’s National Museum of Natural History, provide new evidence that modern plate tectonics, a defining feature of Earth and its unique ability to support life, emerged roughly 3.6 billion years ago. The study, published May 14 in the journal Geochemical Perspective Letters, uses zircons, the oldest minerals ever found on Earth, to peer back into the planet’s ancient past.