Noah’s Ark in the Navajo

The picture below was sent to me by Tom Anderson, one of the participants in our 2017 Talking Rocks Tour. He noted that he had been so preoccupied with looking for dinosaur tracks that he failed to see the obvious feature on the sky line. It was only after he arrived home and was reviewing his photos that he realized he had a picture of Noah’s Ark.  Hope you can join us for the next tour, this fall or next spring. Who knows what we might find.  🙂

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One Limit on Bias in Geology–Money

It’s important to realize that geology is not purely theoretical. Because of the centrality of historical interpretation to the practice of geology, we might be tempted to think that geology is as susceptible to bias as political history. However, geology has multiple checks on the power of bias. One of those checks is mining. Mining puts geological theory to the rude and ruthless test of money. Is this mine worth the investment? When the hole is dug and the ore is assayed, the theory turns into hard, cold fact–you make money or don’t. Either way, the mine might become a photo shoot.

IMG_20170604_183728  This structure is the head of a tram that carried ore from mines on Treasure Hill above Pioche, Nevada, to a mill down in the valley. In 1928 it cost 6 cents a ton to deliver a ton of ore to the mill via this aerial tram.

Geology, not mere opinion

 

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One of the nice things about geology is you can see it. Your first or second interpretation may need to be modified after further investigation, but concrete, tangible reality exists, and we can return to it repeatedly for more information. In geology, opinions frequently can be corrected by facts, facts that can be verified or falsified by direct observation. This high regard for concrete, tangible reality–stuff you can see and touch–is central in our Talking Rocks Tours.

The picture is of Basin and Range country in central Nevada.

Tracks in the Navajo

I camped for a couple of nights at the top of Hog Canyon Road outside Kanab, Utah, to do some geological prospecting.

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Specifically, I was looking for protosuchus burrows. (This animal was an ancient version of crocodile.) I found some anomalous structures in the sandstone that might be burrows, but nothing with the kind of definition I was hoping for.

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However, I noticed the sand around my camp was covered with tracks made by bugs and lizards.

Then up on the outcrop where I was prospecting, I found this rock with tracks reminiscent of the tracks in the sand.

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Not exactly dinosaur tracks, but still pretty cool.

These tracks in the Navajo Sandstone tell us that when these sand dunes were created, there were living animals present running around on them. The animals in this ancient neighborhood ranged in size from worms to the size of horses judging from the tracks they left. (I mention horses only for size comparison. There are no modern mammal tracks in the Navajo.)

From the sublime to . . . well . . . the mud.

Talking Rocks Tour 2017: Buckskin Gulch on day five. A fantastic hike. One group did the full twenty-mile loop. Others did about five miles. Notice the person (the very tiny person) in the photo. The geology lessons we saw in this slot canyon were dramatic.
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The walls of the canyon towered over us. There were flood deposits that spoke of cycles of deposition and erosion inside the canyon–obviously more recent than the formation of the canyon itself. Note this package of debris wedged into the canyon above Bryan’s head. Think of the force of the water required to pack all that woody debris so tightly that long after the water was gone, the debris dam remains.

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I was endlessly fascinated by the mud on the canyon floor. Ripple patterns indicating different rates of water movement, different viscosities of the water (due to mud suspension), channel shape, and who knows what else. In addition to ripple patterns we saw mud cracks, mud curls, mud imprinted with dog paws and human feet, mud sprinkled with red sand from a passing wind storm above the canyon.

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We had mud inside our shoes, mud on our clothes, mud everywhere. It was lovely.

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A Mega Giga Flood

This evening I listened to a presentation at the monthly meeting of the Northwest Geological Society. The lecturer presented a new theory about a gargantuan flood created by the rapid release of waters ponded in the Arctic basin. The flood event was 14,000 years ago. The damming mechanism was the same as the for the Missoula Floods–a glacier, or in this case glaciers. Alpine glaciers from Siberia and Alaska closed off the Bering Straits. The rivers emptying into the Arctic provided so much fresh water that the Arctic itself became a fresh water body.

Is was an interesting argument. I’m going to look further at the handouts.

Devotees of Noah’s Flood will love it. If the theory turns out to be sustainable under cross examination and further research, it will be an even larger flood than the flooding of the Mediterranean basin. It will be the largest flood ever. –well, except for Noah’s Flood, if you believe the traditional telling.

One of the problems with Noah’s Flood is that is doesn’t work to explain any major features of geology. Floods have fingerprints, footprints. And no one has found the fingerprints of Noah in the geologic record.

The cool thing about geologic theories, you can go and check out the evidence. I’m ready to get a helicopter and head north and investigate the landscape. That would be fun!

Truth Tellers, Truth Seekers

I’ve taken a couple of geology classes in college–an intro course at Suffolk Community College and non-silicate mineralogy at University of Akron. I’ve read books about geology. I’ve spent a few weeks hanging out with a geologist who was doing field work. I have found things in the field that were relevant to current investigations. I thought I kind of “got” geology. Then I decided to read more seriously.

This past fall I read a Sedimentology and Stratigraphy text. Now, I’m working my way through a Structural Geology text. Even though these are still fairly basic textbooks, one fact leaps out at me: the science of geology includes oceans of data. These textbooks are densely packed with information, with data. Of course, there are interpretations. There are theories. But page after page impresses me with the amount of hard, concrete information that has been gathered by people studying the rocks. This information is the foundation of geology. Amateurs who imagine that reading a few creationist articles or books qualifies them to make pompous statements about the validity of the science of geology are fooling themselves.

Of course, there are lots of debatable points in geology. The reason we are aware of these elements of geologic theory that are problematic is because geologist publish articles about them.

I am committed to deepening my comprehensive knowledge of geology. I hope to be able to ask a few hard questions. But the more I learn, the more respect I have for the scientists who spend their lives exploring, probing, interrogating the earth. They are pursuing truth. I will join them.

Story-telling Rocks

Rocks tell stories. Sometimes the stories are obscure, enigmatic, even, and our interpretations are debatable. Other times, the stories are straightforward, unambiguous, incontrovertible. Once such story is written in the rocks along Kolob Terrace Road in Zion National Park. These pictures are from my trip there in May, 2016.

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As I started up the valley there were stories begging to be read. The above photo shows evidence of five different “events.” In the foreground, filling the bottom half of the photo, we see a pile of sand and gravel piled against the bank in the background. In the center, there is a small exposure of fine-grained, thin-bedded rocks. Above them is a mess of cobbles and sand and mud with large black rocks in the upper part of the mess. A closer examination shows that this mess is actually two different layers–a lower layer without the basalt boulders, and an upper layer with the boulders. Each of these units–the sand pile, the thin red layers, the coarse layers, and the material at the top–was formed by distinct processes. The process that formed the thin horizontal layers in the dark red deposit could not also create the coarse deposit with the basalt boulders in it. Moving boulders takes a lot of energy. The basalt boulders came down the canyon in a massive flood that would have swept away everything in its path and jumbled everything it touched. That kind of torrent could not also form the rock-free layers of fine-grained mud. Laying down a flat, thin layer of mud requires slow-moving water. There is also an obvious order to some of the chapters of this story. The thin reddish layers had to be deposited before anything else in the picture. One obvious question raised by this picture: where did the basalt boulders come from? Most of the rock in that part of Utah is sandstone and related sedimentary rocks. Where did this volcanic stuff come from?

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Just a mile or two up the road is this view. The rocky horizontal layer capping the light-colored slope in the center of the picture is a lava flow. The same flow is seen above the road where the road turns to the right. That’s the likely source of the basalt boulders. I have driven this road before and noticed the lava flow. I know that higher up the canyon, there are two or three cinder cones marking the source of the lava flow. I’m thinking the interesting part of this story is going to be the erosion around the lava flow. At the time of the lava flow, the canyon was only half as deep as it is today. After the lava flow came down that smaller, narrower canyon, the water continued cutting, creating wider, deeper canyons on both sides of the lava flow. I was looking for a good place to get a picture of this perched lava flow, sitting on top a ridge in the middle of the canyon when I got interrupted.

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What’s going on here? We see the lava flow on top. We see fine-grained layers on the bottom. But what’s that in the middle? It is another flood deposit. The flood apparently cut a channel in the fine-grained material and filled it with great chunks of rock along with mud and sand.

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A closer look at the chunks of rock incorporated in this flood deposit. I call them “chunks” instead of “boulders” because they are so angular. They have not traveled very far or they would have been more rounded. When I looked even closer, I was even more surprised.

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Conglomerate! The boulders are not basalt. In fact, in this layer there is no hint of basalt inclusions. This flood happened before lava was in the neighborhood. The basalt came later and buried the flood deposit. Where did this conglomerate come from? It looks like Shinarump, a layer of rock that lies below the Navajo Sandstone. Navajo Sandstone is the rock that makes up the famous cliffs of Zion NP. Shinarump is older and lower than the Navajo. The Shinarump has a lot of petrified wood in it, so I looked. Sure enough, just feet away I found a big piece of petrified wood in the matrix.

pic 0516 124341. Petrified wood in flood matrix.IMG_20160516_124341 (1)

Studying this flood deposit added details to the story of the canyon. The canyon had to be cut down through both the Navajo Sandstone and the Shinarump before the lava flow happened. At the time of the flood that deposited these conglomerate blocks, the canyon was probably substantially narrower than it is now. The flood undercut the canyon wall below an outcrop of Shinarump conglomerate. Chunks of the Shinarump layer (and pieces of Navajo Sandstone above it) fell into the flood and were transported a short distance before the flood lost the energy require to transport boulders. The existence of chunks of sandstone in this flood deposit is further indication this material was not transported very far. Sandstone cannot survive very long in the rough and tumble world of violent floods.

pic   123959. Sandstone block inn flood deposit. IMG_20160516_123959 (1)

In the two photos below we see the right and left sides (looking upstream) of the lava flow hanging above the canyon. The horizontal layers farther to the right (in the first picture) and to the left (in the second picture) on the far sides of the canyon, are not lava, but layers of sedimentary rock. At this point the flow is less than a quarter mile wide with the canyon dropping hundreds of feet down on either side. From the air, the flow would appear to constrict and flow along the top of a ridge in the middle of a large canyon!

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A view of the lava flow farther up canyon. Notice the flood deposit under the lava. This is a very different appearing deposit from the flood deposit previously mentioned. I don’t know if this is the same flood event, just farther upstream, or an entirely different flood event.

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Cinder cones at the top of the canyon marking the source of the lava flow.

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The water-rounded basalt columns in this photo are the edge of a lava flow that originated near the cinder cones pictured above. However, this flow traveled down a different canyon (into Hop Valley). Apparently as the water was cutting the canyon around the lava flow the flow of the water was concentrated on the lava at this point long enough to carve its signature into the rock. But that’s another story.

The moral of the story. First, there is no need of a moral for people like me. I’m fascinated by the stories written in the rocks, fascinated by all the details. I can get happily lost for days at a time deciphering the story written in a single canyon. But if you’re looking for a moral, here it is: rocks tell stories. We can read many of the small chapters in the story. If we are going to tell a grand, all-encompassing story about the rocks, that big story probably should incorporate the simple plots legible in the chapters.