Researchers have revealed a crucial segment of the Colorado River’s past, resolving a geological conundrum that persisted for many years. Recent findings indicate that approximately 6.6 million years ago, the river flowed into a long-lost lake located in what is now Arizona, remaining confined there until it eventually overflowed into the Grand Canyon around 5.6 million years ago. Through the examination of microscopic zircon crystals, scientists traced the ancient trajectory of the river and uncovered connections between sediment deposits found both upstream and downstream. This revelation significantly alters our comprehension of the Colorado River's development and its role in shaping one of the nation's most recognizable terrains.
