Galicia PAU Geology And Environmental Sciences Practice Questions - Galicia PAU Geology And Environmental Sciences Geología Y Ciencias Ambientales Exam

They record periodic reversals of Earth's magnetic field frozen into basaltic oceanic crust as it crystallizes and spreads from mid-ocean ridges. They indicate that continental rocks periodically gain and lose iron content during intense metamorphic episodes. They demonstrate that solar wind variations induce localized magnetism in marine sedimentary layers near oceanic trenches. They show that Earth's mantle undergoes magnetic polarity inversions every 100 years.