Sentences with phrase «younger volcanic deposit»
A younger volcanic deposit lying in the rock above these fossils includes zircons, tiny bits of silicate mineral that often contain trace amounts of uranium.
http://www.sciencemag.org/ Not exact matches
Geologists have long believed that these minerals were formed by volcanic activity, but in a new study, researchers from McGill University in Canada argue that the silica - rich minerals may have been deposited in the crust of a young Earth by «silicate rain.»