Geologic history of the Sierra Nevada

Stanford researchers have been looking at Oxygen isotope ratios to figure out the elevation of various parts of the western mountains in the past. With this timeline, they can infer the history of the Sierra Nevada mountains. SFGate has the story: How Sierra Nevada rose from the Jungle.

This scenario of a distant past for California and the West comes from new findings by a team of Stanford scientists who have collected nearly 3,000 samples of fossil rainwater absorbed by ancient rocks and glasses formed from melting volcanic eruptions to re-create the geologic history of a region that once extended east to what is now Nebraska.

“There have been many competing hypotheses about the rise of the Sierra Nevada in recent geologic time,” said Chamberlain. “One view suggests there was once a huge plateau in the West known as the Nevada Plano; but all our isotope data, taken with other records, shows clearly that the wave of uplift beginning about 50 million years ago and ending some 20 million years later saw the Sierra rising on the west side of Nevada well before it reached its present height.”

There are a lot of ways this geologic history influences us today. It is why gold (and other minerals) can be found in various places. It is why the eastern slopes have a more difficult grade than the western ones. It is what created the scenery we enjoy. Studies such as described in this report help gain understanding about how it happened but do take note that there are “competing hypothesis.” That means there is still a lot to learn.

Comments are closed.