A Brief History of Geological Time, as told by the Grand Canyon

Now you can skip right to the Grand Canyon National Park’s geology homepage for details, but there’s NO way I’m allowing you to pass my blog without seeing a few geological highlights about this World Heritage Site.

First of all, as one of the most studied geologic landscapes in the world, the Grand Canyon offers us a sense of “deep” time. The concept inspires in me a sense of awe akin to smashing two Higgs bosons together (if that’s possible) or extracting some important insight through deep hierarchical learning.

Think about it this way: the earth was formed 4500 million years ago in the Hadean Era. The Grand Canyon offers rock formations that span over 1800 million years. Boom, that’s over a third of the earth’s history right there before your eyes.

The Grand Canyon offers us almost half (180 degrees) of the earth's geological history. Clock image courtesy of imgarcade.com.
The Grand Canyon offers us almost half (180 degrees) of the earth’s geological history, from the Proterozoic era onward. Clock image courtesy of imgarcade.com.
The story of rocks
The story of rocks layer by layer. 
Bouldering across rock strata and time
Bouldering across rock strata and time

These rocks’ immense age and fossil records show transitions in environments far different from present-day Arizona, or the world for that matter. In brief, continental drift caused the Pacific Plate and North American Plate to collide some 1800 million years ago, forming the ancient Rocky Mountains range Northwest of the canyon all the way up to Sierra Nevada. Then, a series of advancing and retreating ocean coastlines littered the flat Arizona plains with sedimentary rock layers and embedded them with time-telling fossil records. Eventually, the coast retreated and these mountains were eroded into a level plain. Shoutout if you took Geography 40 with me at Berkeley with Prof Chiang. That was the best.

Some 5 million years ago (relatively young in the scheme of things), the Colorado River began to take its modern course, flowing through the Colorado Plateau and into the Gulf of California. As I mentioned in my last post, the Grand Canyon’s North Rim is actually 1000 ft higher than the South Rim (where we stood) because the Colorado Plateau began to uplift some 17 million years ago. As a disclaimer, all the facts in this paragraph are still under debate by geological experts. Such is the nature of knowledge.

5 million years ago: impact of the Colorado River in forming the Grand Canyon. 
The Colorado River carried everything downstream, cutting deeper into the canyon. 
And there you have it: erosion's masterpiece.
And there you have it: erosion’s masterpiece.

What really astounds me is the power of erosion. Pause and consider how this gaping canyon began as an average river at ground-level. It flowed and flowed for 5 million years, wearing away the rocks and cutting the canyon down to the bottom of its heart its present depth of 6000 feet (1.14 miles) at its deepest point. All because of the simple element that is water. Distance is deceiving: I’d never have guessed that the opposite rim of the canyon is 18 miles away. That’s longer than a half marathon! No wonder astronauts search for this mind-boggling sight from space.

I’m just waiting for iOS/ Google Glass developers to make a “Star Walk”-like app that lets me scan these rock formations in real-time to parse their geological history.

As evening drew near, I left the Yuvapai Geology Museum and made efficient use of time by taking the shuttle back to the parking lot and driving to a different lot to take the red shuttle to Mohave Point for sunset. From Mohave Point, you see an endless expanse of the Arizona rock plain, with visibility 40-50 miles- an impossibility in Hong Kong. I don’t even have to close my eyes to imagine this land engulfed under an ocean. It was a time-travel kind of moment.

When the sun dipped behind the clouds and melded into a chromatography of colors, it got cold very quickly. We were lucky the last shuttle bus of the day came right away. Our driver was the friendliest guy ever and simply hilarious. He warned us about the 5000 elks that roam the area/ Highway 64 on which I drove to return to our motel. These idiots are the cause of 200 accidents a year, 90% in the nighttime. I did not run over any elks tonight (breath of relief) and slept with peace of mind.

Stay tuned for Antelope Canyon (see your Apple/ Microsoft desktop sample images for reference) and an hour of Utah tomorrow.

Sunset 1
Sunset 1 from Mohave Point
Sunset 2
Sunset 2 from Mohave Point
Sunset 3... And the day's gone
Sunset 3… And the day is gone

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