یک ابر صخره گم شده ممکن است میلیاردها سال از دست رفته گرند کانیون را توضیح دهد

A lost mega-cliff may explain the Grand Canyon’s missing billion years

A colossal cliff system created as the supercontinent Rodinia broke apart may have exposed the heart of the Grand Canyon nearly a billion years before the Colorado River carved it. The ancient landscape could also help explain why enormous sections of North America’s geological record appear to be missing.