Etched onto the steep walls of Arizona's 6,000-foot-deep, 277-mile-long Grand Canyon are clues that chronicle the sweeping changes the region has experienced during the past two billion years. The canyon's colorful layers narrate tales of ancient environments come and gone, from lofty mountain ranges and tropical seas to a Saharan-scale desert that once stretched across much of western North America.
from Latest Science News -- ScienceDaily https://ift.tt/2kS2Qf8
via IFTTT
Subscribe to:
Post Comments (Atom)
No comments:
Post a Comment