Thursday, October 28, 2010

Grand Canyon Part 5: The River

IMG_7588We moved our camp down to the next- and only real other- junction in Tuckup, that of the main canyon and the Northeast arm, pausing to down-scrabble and hand off packs several times. Shortly before arriving at the junction, we passed under a feature I’ve encountered spanning no other canyon on the Colorado Plateau: a conglomerate arch.

I explained conglomerate rocks last year closer to home, in City Creek Canyon. The hunk of conglomerate that the arch is carved out of is similar, though I’m sure it formed at a different time. But I don’t know when it formed. I suspect it was deposited in an existing channel in the Muav, but at a much later time than the Temple Butte formation we scrambled up in the last post. But I haven’t pinned it down in any of my geo sources*.

*My best guess is that it was deposited in the last million years. I know that there are deposits from basalt flows in Tuckup and its tributaries laid down between 700K and 1M years ago. The arch/bridge appears to be made of conglomerate, not breccia**, but I wonder if some of the eruption and flow events of that period could be related to the deposits that formed the conglomerate. Just a hunch.

**Which I explained in the same post.

IMG_7598 In any case, it’s not technically an arch, but a natural bridge, in that water runs under it. Specifically it’s a waterfall natural bridge, a type that is created by subterranean stream piracy*, which is a fancy term for when the flow of a stream gets diverted underground into openings/crevices beneath. The flow eventually undercuts the surface, leaving a bridge supported by the former stream banks.

*Is that the coolest term ever or what?

SS Piracy The arch looks crumbly and fragile- like it’s going to fall on you any minute. Guidebook author George Steck claims that it’s stronger than sandstone, but The Natural Bridge and Arch Society* calls it a “relatively fragile structure.” In any case, we didn’t try jumping on it.

*Man, it is like there is a society for everything.

IMG_7687 Our new camp was one of the coolest sites I’ve ever camped at, on ledges maybe 30 feet above the canyon bottom, with easy access to water, plenty of flat space for sleeping (pic left = my sleeping bag on ledge), cooking and lounging, and an overhang for rain protection (not that we needed it.) And the view from the “porch” was fantabulous, though our night sky was just a narrow band between the canyon walls. Ledge sites are nice also because you cook and sleep on rock, not sand, which means that everything- you included- feels clean, not gritty. If the site had any logistical downside, it was the necessary hike/scramble to access enough soil to dig a cat-hole*.

*To, you know, poop.

Side Note: While I’m on the topic, decent campsites in Tuckup Canyon are extremely limited. Bed viewThis is because the canyon is narrow pretty much the whole way from about a mile below Shaman’s Gallery on down to the river, which makes for great hiking, but tricky bedding. Really the 3 main camp-able spots are the junction with Cottonwood Canyon, the junction with the Northeast arm, and the beach on the river. Fortunately the Park Service limits the number of backpackers in the canyon via a permit system, but competition for sites is still possible.

ASteve hole caption We spent the afternoon exploring the Northeast arm, a fun scramble of ledges, chutes, pools and tunnels, before returning to camp, eating and crashing.

Side Note: Something else about camping. It was remarkable how much warmer the nights became as we progressed down-canyon. Thursday night up on the rim at ~5,800 feet there was frost when I awoke. At the Cottonwood Canyon junction (~2,700 feet) it got down into the low 50’s. At the Northeast arm junction (~2,100 feet) it didn’t get below 60F the whole night. Oddly, the days were still quite pleasant, never above ~75F.

IMG_7557 The next morning we packed lunch, rope, a couple of carabiners and headed down-canyon. By this point there was water pretty much continually, and after a couple of miles we reached a deep pool with a little waterfall that looked difficult to climb back out of an the return. Bright Angel We backtracked a short way and found a faint bypass trail that soon climbed high up above the canyon bottom. The (very exposed) trail followed a sloping band of shale-y soil that I realized was the Bright Angel Formation, consisting of extremely fin-grained shale laid down some ~515 - 530 million years ago that always forms slopes, erodes easily, and sometimes has a faint green-ish tinge. The green color comes from Glauconite, which is a kind of mica that forms in sediments either as or after they transform to solid rock.

IMG_7669 Side Note: We passed under a huge, exposed hanging garden here, probably fed by seeps occurring where the Muav limestone meets the Bright Angel shale.

Dropping back into the canyon bottom, we were on/in rock again, but now a different rock- the Tapeats Sandstone. Tapeats, laid down ~530 – 545 MYA is thought to have been formed in tidal flats, tidal channels and beach deposits in and by a IMG_7666Cambrian sea. It features frequent ripple marks and trilobite fossils. From a hiker’s perspective, it seems to erode into many, many horizontal ledges, forming open plazas separated by repeated staircases. In spots where it gets steeper, the ledginess provides ample finger and toeholds.

In and by the larger plaza-pools, we began to notice a number of toads, which on closer inspection, were decorated with bright red spots. IMG_7665 These are Red-Spotted Toads, Bufo punctatus, and they are opportunistic breeders of the desert Southwest. Normally nocturnal, they became unusually active following rains, quickly mating and laying eggs in pools. The eggs hatch in about 3 days, and mature into toads in 6-8 weeks. The same rains that caused us such trouble on the drive in were the reason we were seeing so many of them now by day. They don’t “croak” like traditional toads, and we thought them curiously silent. But later I learned that their “croak” sounds more like the high-pitched “chirp” of a cricket, and that perhaps a few of the occasional “crickets” we heard in the evening were actually male Red-Spotteds seeking mates.

Red Spotted caption Bufo is a huge genus, with around 150 species occurring worldwide. As a rule they’re lousy jumpers (especially compared to frogs) and the Red-Spotted Toad tends to walk/shuffle more so than jump (they’re ridiculously easy to catch.) To compensate for their lame mobility, many Bufo species exude defensive, toxic skin secretions. Bufo boreas, for example, the common and widespread Western Toad (which you’ve undoubtedly seen if you live in the Western US and often hybridizes with B. punctatus) produces skin toxins that repel many predators. Other species produce skin poisons that can kill a large mammal that eats them, and some of these poisons, such as that secreted by B. alvarius, the Sonoran Desert Toad, are hallucinogenic (leading to the whole licking-toads-thing, which- like Datura- I recommend you not mess around with either.) But Red-Spotteds produce no such toxins that I’m aware of (which is maybe why they’re nocturnal).

IMG_7636 One of the interesting things about a worldwide genus is where it came from. In the case of Bufo, this question has been the subject of various hypotheses for decades. The greatest diversity of species seems to be in South America and Africa. One hypothesis was that they originated in Africa, spread throughout the Old World, and then migrated to the Americas via (an earlier incarnation of) the Beringian land bridge. Another proposed the exact opposite, with a South American origin. But more recent genetic evidence seems to suggest elements of both, and yet neither, hypotheses.

Apparently Bufo originated in Gondwanaland back when South America and Africa were either still connected, or close enough for them to spread between the 2 continents. The African Bufos colonized the Old World, and the South Americans colonized the New. As the 2 groups did so, they adapted to different yet similar environments, creating morphological similarities that confused earlier researchers, and which had to be unraveled through DNA analysis.

Bufo’s story within the Americas is pretty cool: all North American Bufo species North of central Mexico appear to be monophyletic, the result of a single migration event. Central Mexico is a barrier for many species, particularly a water-loving amphibian. And even more interesting, though it’s not clear exactly when the earlier Bufo pioneers reached Central America from South America, it appears almost certain that it happened before the 2 were joined via the Great American Interchange*. This is less trivial than it sounds. Toads have water-permeable skins, and are adapted to fresh water**. Sticking most toads in saltwater is a good way to kill them. So continent or island hopping- even via rafting- by a freshwater toad is a pretty tricky undertaking. Whatever the specific details, it appears that not just Red Spotteds, but many of our most common toads in the US, have a fantastic migration history.

*Which I explained in this post.

**The so-called “Salt Toad” of California, which is actually a subspecies of Western Toad, may be an exception. It lives in salty swamps. The Marine Toad, B. marinus, cannot tolerate seawater, despite its name.

We continued down-canyon, each bend revealing a new series of plazas, pools and little waterfalls.

In March 1985, my college roommate* and I flew to Phoenix for Spring Break. IMG_7641 We rented a car**, drove up to the South Rim, and hiked to the bottom of the Grand Canyon. At the time of course I knew next to nothing about the Grand Canyon, or the wider Colorado Plateau in general, but I was blown away by the scale and beauty of the place. In the decades following, I’ve moved out West, spent countless long weekends exploring the Colorado Plateau, often on the fringes of the Grand Canyon, and in the course of doing so learned plenty about the flora, geology, human and natural history of the region. But somehow, even after a quarter century of exploring and dinking around in the backcountry, I’d yet to return to the bottom of the Grand Canyon. So I was really, really looking forward to reaching the river.

*Yup, “Dan” from the Datura post.

**In 1985, an under-25-year-old could still rent a car. And you could reserve a bunk at the Phantom Ranch with about 2 week’s notice.

Tangent: Moments like this lead me to where-does-the-time-go type thoughts. 25 years is a long time, and I never imagined it would take so long to return. It just seems like we never have enough time. In a comment to my last post, KanyonKris mused about the benefits of slowing down the aging process so that we could enjoy more years of old age. But when I think about it, I’m not really sure the long-and-healthy-retirement-dream is the answer*. We already live for several decades- plenty of time to get around to doing, well, everything. I suspect that if we were given another couple of healthy decades, we’d just manage to suck that up with busy-time as well.

*Besides, if we all live healthier and longer, we’re all going to retire later. The demographics won’t support an ever-increasing pool of long-lived geezers retiring in their 60’s.

The irony here is that when you do something really cool, like hike to the bottom of the Grand Canyon, you remember it. I can barely remember what I did a month ago at work. And if you asked me to list things I remembered over the last decade, hardly any of the events or happenings I recalled would be work-related. Remembering stuff is worthwhile; it’s high-value. The stuff of our brains, the material us, is constantly being replaced. There really is no you*. What there is, is the story of you, the storybook you build over your lifetime and carry around in your here-right-now ephemeral head. And that storybook is written from experiences recorded as memories**. If you’re not recording new memories, if you’re not doing stuff worth remembering, then your storybook isn’t being written anymore; it’s just sitting on the shelf, no matter how “busy” and “active” you seem to be…

*I went into this in more detail in this post.

**I went into this in more detail in this post.

Dropping out and being a deadbeat isn’t the answer. Although money doesn’t bring happiness, lack of it, ironically, brings great and consuming unhappiness. The trick is figuring out the balance. That sounds easy, but it’s not, because social interaction, by its very nature, drives us off-balance. We constantly compare our attitudes, values and lifestyles to those of whom we interact with. That’s not a bad thing; we learn and grow from the examples around us, and that interaction can lead us to improve and excel scholastically, professionally, athletically and otherwise. The challenge is structuring our lives so we’re regularly and continually doing stuff in the things-we-remember category and making sure that we’re prioritizing our big high-value goals (hiking down Grand Canyon, learning a foreign language, visiting New Caledonia) alongside our big high-necessity goals (key family relationships, raising offspring, providing for loved ones.)

You can’t do everything. So if you’re going to make the balance work, you have to figure out what you’re not going to do, or spend time and cycles on. I call this Selective Disentanglement (SD), which is probably just a fancy term for “figuring out what I should blow off…” I think I’ve been getting better at SD over the last few years, and over the coming year, I’m going to try and ratchet it up a notch…

A short while later we came to the expected final pour-off, a 40-foot drop we’d need to detour around. Steve, walking ~30 feet ahead of me reached it first. He looked down, raised an arm, and called “Hi!” About a dozen people stood down below looking up, the first “others” we’d seen in a couple of days. They were rafters, hiking up from the river. There was water falling from the pour-off in a little waterfall. In the closed space of the canyon it made quite a little racket, and we had to shout to hear each other. I called down, “How far to the river?”

“200 yards- you’re there!” came the shout back.

Steve and I backed up 30 yards or so and found a place where we could pick our way up, IMG_7661above and around the pour-off on the West side. We traversed a bit further, and then found it- the chute from the guidebook we’d need to down-climb. It wasn’t especially technical (maybe a 5.3?) but it was exposed and far from help. We rigged a hand-line for Steve to descend first, to a ledge ~ 20 feet above the canyon floor. I followed, bringing the line with me to use for the last portion of the descent.

Side Note: If you do this trek and are a risk-averse non-climber, bring 2 ropes and 2 carabiners. There’s a good bolt for each section. The first rope should be 50 feet, the second one 20. If you’re not coming back up, one 100 foot rope (to pull through) will be fine, A hand-line is fine; you don’t need to rappel.

Two of the rafters* backtracked to watch our descent, and gave Steve helpful toehold guidance on the down-climb. When we arrived on the canyon floor they introduced themselves as Lou and David, and offered us food and beer at their camp. Together we picked our way down the last few bends of Tuckup Canyon.

*The rest of the party, which included 2 climbers (they actually own a climbing gym back home in Tennessee) managed to ascend the pour-off and day-hike further up-canyon.

IMG_7660 I asked them how the water was (with a mind to go for a dip…) David replied, “It’s f***ing* muddy!”, and my heart leapt. In the old days, before the dam, the Colorado was pretty much always muddy/silty. But after the dam was built, the river ran with cold green waters from the bottom of Lake Powell, and that’s how I saw it 1985. But the rains of the past week had flushed mud and silt out of the side canyons, filling the river, and making it appear, temporarily at least, like its old self.

*The rafters, with their Tennessee twangs and “colorful” language, were highly entertaining to listen to. The F-word graced every other sentence. Our favorite usage-instance was when one of them, relating a story about a nude sunbather they had encountered earlier in the trip, used it in the middle of the word, “asleep”, as in “a-f***ing-sleep!)

Extra Detail: The post-dam, colder flows have led to significant changes in the canyon. Cold-water trout have replaced native Squawfish and Chub in many places and prey upon their young. At least 3 native fish species have disappeared entirely. The presence of trout in the now-clear waters has attracted Bald Eagles, who first appeared in the canyon in the mid 1980’s. Then there’s the whole beach/shoreline/vegetation thing, but that’s a whole post in and of itself…

IMG_7642 As we walked the last little ways down Tuckup we began to hear a distant “wind” or sound. First a whisper, then building, the road of the river. Around the final bend through the Tapeats slot, the wind was accompanied by a growing light- the bright, wide-open-space daylight of the inner gorge. Steve and I walked faster toward the light and the roar, Lou and David trailing a bit behind us, like modern-day guardian angels.

And then all of a sudden the slot IMG_7648opened up into the inner gorge, and there was light and sky and noise and a highway of roiling, fast-moving water before us, in all of its opaque, muddy glory and power and wonder, backed on the far side by nearly vertical Tapeats cliffs, and finally, 25 years later, I was back.

Geo-Tangent: What I had expected to see, but did not, was one more geologic formation- the Vishnu Schist. Almost 2 billion years ago, in what is now Northern Arizona, a mighty mountain range built up of metamorphic rock. The world was different then; when those mountains began to rise, Earth was fresh from the Oxygen Catastrophe, when recently-evolved cyanobacteria first filled the ancient air with oxygen*, and the ensuing Huronian Glaciation**. A day was only 20 hours long, and a year contained 450 of them.

*Initially the freed oxygen combined with (oxidized) iron. But when no more could be oxidized it began to accumulate in the atmosphere, causing a mass extinction of anaerobic microbial life.

**An earlier, similar, “Snowball Earth”-type event.

Inner Zoom The mountains rose and rose, till they towered high as the Himalayas. Over millions of years following, seas washed over and gradually eroded them down to their base. But the roots still lie there, and elsewhere in the canyon, further East, up around Phantom Ranch, the ancient rock, the Vishnu Schist, is exposed below the Tapeats sandstone, lining the inner gorge.

Extra Detail: Between the Tapeats and Vishnu formations lies the Great Unconformity- hundreds of millions of years of missing rocks that were eroded away prior to the formation of the Tapeats by advancing seas. In some parts of the canyon intervening Pre-Cambrian layers appear- Chuar, Nankoweap and Unkar- and where they do, the Great Unconformity defines the missing layers between them and the Tapeats, while an earlier gap- the Pre-Cambrian Unconformity- defines the missing layers between them and the Vishnu.

But (as I learned later) at the Western end of the Grand Canyon the Vishnu is not exposed, and the Tapeats continues clear down to the river in near-vertical cliffs. The roots of the Old World remained hidden beneath us.

Lou and David produced beers and snacks, which seemed wickedly luxurious in the middle of a backpacking trip. I kicked off my shoes and ran my toes through the warm sand while we IMG_7647chit-chatted about our trips. After a few minutes I got up and wandered barefoot down to the water’s edge. I stood for a moment, taking in the noise, light and tumult of the river, then stripped, waded out hip-deep, and plunged into the silty Colorado.

Note About Sources: As with earlier posts in this series, much of the geologic info came from Bob Ribokas’ Grand Canyon Explorer site, Stephen R. Whitney’s A Field Guide to the Grand Canyon and Wikipedia. Additional geologic and hydrological info for this post came from Volcanic Rocks of the Grand Canyon Area, George Billingsley, Deposition of the Tapeats Sandstone (Cambrian) in Central Arizona, Richard Hereford, and the website of the Natural Arch and Bridge Society. Info on the Red-Spotted and other toads came from David Williams’ A Naturalist’s Guide to Canyon Country, the Arizona-Sonora Desert Museum* website, Thomas Scott’s Concise Encyclopedia Biology, and The History of a Nearctic Colonization: Molecular Phylogenetics and Biogeography of the Nearctic Toads (Bufo), Gregory B. Pauly et al.

*Can you believe I have not been there yet? How is that possible?? Adding to the high-value goal list right now…


KanyonKris said...

"The trick is figuring out the balance. That sounds easy, but it’s not, because social interaction, by its very nature, drives us off-balance. We constantly compare our attitudes, values and lifestyles to those of whom we interact with. That’s not a bad thing; we learn and grow from the examples around us, and that interaction can lead us to improve and excel scholastically, professionally, athletically and otherwise. The challenge is structuring our lives so we’re regularly and continually doing stuff in the things-we-remember category and making sure that we’re prioritizing our big high-value goals (hiking down Grand Canyon, learning a foreign language, visiting New Caledonia) alongside our big high-necessity goals (key family relationships, raising offspring, providing for loved ones.)"

Balancing the forces in life is a key principle with me and you expressed it so clearly - well done.

My takeaway from interacting with this series of Grand Canyon posts is: I need a desert hike. I love the bike, but my balance needs some on-foot time. I'm thinking the upper forks of Bluejohn Canyon, interested?

Watcher said...

And here I was with no "tickets on the fridge", just itching to get back in the canyons. Bluejohn? I am in!

Jube said...

Very cool post. Way cool muddy river pics! Sorry you didn't get to lay your hands on the Vishnu.