Smithsonian researchers trekked to a remote site in northern Canada to collect four-billion-year-old rock samples that could ...

This rock recycling is a process called the rock cycle ... compressed and glued together.Metamorphic rocks are formed from other rocks, igneous or sedimentary, which are heated and compressed ...

These plagioclase-rich igneous rock formations ... "Because the mantle was hotter in the past, this process directly connects the formation of massif-type anorthosites to Earth's thermal and ...