Wayne Ranney shares Buffalo Park's juicy geologic story

Buffalo Park: A Time Travel Tale

By Wayne Ranney

March 3, 2020
http://www.wayneranney.com/
https://earthly-musings.blogspot.com/
https://all-in-a-days-karma.blogspot.com/

(In the mid-1970s, Wayne Ranney wandered into the Grand Canyon and never came out. He worked as a backcountry ranger, finished his geology degree at Northern Arizona University and became a river guide on the Colorado and San Juan rivers. Wayne then received an advanced degree in geology and began working as a geologic interpreter around the globe. He now serves as a geologic educator, an award-winning author, and lectures on outdoor adventures and worldwide expeditions. Wayne leads geology-themed river trips and hikes in the Grand Canyon and the Southwest. Wayne's books are written so that professionals find them useful, while remaining accessible to lay audiences.)

Flagites (people who live in Flagstaff) love Buffalo Park. It’s expansive views north to the San Francisco Peaks and south to Mormon Mountain provide one of the few places in the city where they can see something beyond the trees and get a view of the forest. It’s a place where Flagites can see the wider world that surrounds them.

Strange as it may seem, I think the landscape around Flagstaff is generally not all that interesting. (Okay – cue the boxes of rotten tomatoes and the dishes to be thrown – this is blasphemy from one of Flagstaff’s own. Oh, the horror! The shame!) I admit there is the tallest mountain in Arizona on the San Francisco Peaks. And its little sister, the massive hulk of dacite lava known as Mt. Elden. Sure, it’s beautiful, snow-capped much of the year, and most people’s ideal kind of a landscape. Who doesn’t like mountains and trees?

But my point is this – it’s all just lava rock. There isn’t much variety to it. It’s BORING! I often exude exclamatory ooh’s and ah’s when I see the Mogollon Rim. The same with the road cuts down I-17 to the Salt River Valley. There’s so much variety in the rocks! Ancient lake beds, fossil-rich sandstones, intrusions and lava flows, one never sees the same rocks.

However, there is one Flagstaff landscape I really love and can get excited about – the one at Buffalo Park. The wide views appeal to my inner Homo erectus, those early human pioneers who took off from the homeland in Africa and settled the far reaches of the globe. And the geologic story of Buffalo Park is juicy.

The lava flow capping the mesa where the grasses grow came from the southwest, specifically from Woody Mountain. It occurred about 5.97 million years ago – call it 6 million for ease of remembering. It oozed down the regional slope in the northeast direction, long before the San Francisco Peaks or Mt. Elden were even a gleam in Mother Nature’s eye. 6 million years ago, the climate was a bit warmer and NONE of the volcanoes seen today were there to block its path.

Its trip to the northeast however was interrupted. But that obstacle has since eroded away. Where the northeast edge of that lava flow now stands, a retreating cliff of red Moenkopi sandstone and the pebbly Shinarump Conglomerate graced the landscape. Today, this same escarpment is located about 35 miles north just this side of Cameron. (Yep, slightly tilted packages of sedimentary rock often “retreat” down slope and in 6 million years, this one has retreated that far).

Imagine the scene 6 million years ago! A nascent volcano erupts a small cinder cone (Woody Mountain). As the gases are exhausted during the course of the eruption, degassed lava wells up into a pool within the cone. It ultimately finds a break where it spills out of the cone as a lava flow. The fluid basalt lava runs downhill for miles – right towards the red cliffs that once buried the present-day site of Coconino High School. The lava pools at the base of the cliff and then turns southeast, running along the base as far as today’s Route 66 (not yet built). Through time,  the red cliffs retreat north, away from the terminus of the lava flow and Switzer Mesa is born!

But how do we know this? Cryptically hidden to all but a trained eye, beneath the northeast edge of the lava flow are the eroded remains of the former cliff. Before the lava came, pebbles from the Shinarump cliffs were being eroded and fell as loose debris to the base of the cliff. These became preserved beneath the lava, frozen in time from that rainy afternoon (why not?) when the lava flow encountered the cliff. Detective work and geologic sleuthing at its best.

These are some of the stories that race through my mind as I walk in Buffalo Park. To be a geologist is to live multiple lives, through many periods of time. And oh yeah, this would’ve been a great place to view that big volcano to the north building itself 2 million years ago.