Sunday, January 21, 2018

A Look Back at Ten Years of Geotripping: Arizona is Going to Get Another Meteor Crater, Only Bigger. And We Know Where and Why.

I've been commemorating ten years of geoblogging with a trip through the archives, looking for some of my favorites. I posted the following twice, once in in 2015, and again in 2016 because as a political issue it continues to simmer. It was also one of the oddest geological issues I've ever come across. My brother took me to Oak Flat during a visit to the Phoenix area, and it wasn't until later that I found out the insidious actions taking place in Congress to destroy the area (for money, of course). How often do we hear of plans to produce a hole larger than Meteor Crater? After the Native American protests at Standing Rock, I think this issue deserves a bit more attention. A recent business POV update can be found here.

When I see a representative insisting that a law must be followed ("Rep. Gosar is pressuring the Forest Service to enforce its rules that limit camping at Oak Flat to 14 consecutive days") when he helped subvert law to bring this situation about, I feel sick about our political system. In any case, like the title says, Arizona is going to get another Meteor Crater-sized hole, only bigger, and we know where and why it is going to happen...
This is NOT a killer asteroid entering the Earth's atmosphere. It is a sun dog over Oak Flat Campground near Superior, Arizona. Oak Flat is going to become a gigantic crater.
...because it won't be a meteor that causes it. It won't be an atomic bomb test. And it won't be because of aliens like those stupid ones in Indiana Jones and the Kingdom of the Crystal Skull. The giant crater will be entirely the work of human beings, and gravity. And it will destroy a place that is sacred to many, and was given protection by a Republican president 60 years ago.
Meteor Crater, Arizona is probably the most famous impact crater on the planet, and is about three-quarters of a mile across, and about 550 feet deep. The coming crater is expected to be about a mile across, and as much as 1,000 feet deep. How in the world is such a thing going to happen?
The town of Superior, Arizona is like many old mining towns of the west. It's depressed, it's poor, and few inhabitants really have a reason to stay. People made a good living out here at one time, mining and smelting copper from huge open pits nearby. But the mines closed decades ago.

But the copper wasn't all gone. With prices up, there is renewed interest, and Resolution Mining Company has outlined a huge ore body, one of the largest in the world. But there's a problem.
It's 7,000 feet beneath the surface.

The normal approach, open-pit mining, won't work. It's far too deep. Normal tunnel mining won't cut it either, because although the ore body is huge, it is low-grade, averaging around 1.5% copper, instead of the 5% or so that is required for profitable tunnel mining. So the company proposes to go after the ore using a process called panel caving (a type of block caving). They propose to start underneath the ore body, design a system of collection tunnels, and then fracture the rock above, allowing it to fall into the collection areas where the ore will be removed.
The process will allow the mining of vast amounts of ore, but what they will be doing will amount to removing an entire mountain from beneath the surface. Holes of such size cannot be maintained as open space underground, so the mine will collapse in a supposedly controlled manner. At the end of the mine's usable "life", the crater is expected to be about a mile wide and as much as 1,000 feet deep. Bigger than Meteor Crater.
There are huge social and political issues. Many people are fully supportive because money, but it's never entirely clear who will truly benefit, and who will actually get the jobs, and which political entities will get the tax revenue to support the regional infrastructure. And there is no guarantee that the mining company itself will maintain economic viability for the next sixty years. Such things are hard to predict, and the American West is littered with abandoned and depressed towns that were promised much and ultimately received little.
And then there is the matter of honor and history. Soldiers chose to die here, defending their homeland and families. When all was lost, more than four dozen of them chose to jump off the cliffs rather than be taken by the enemy. It was around 1870, and the deaths occurred only 1,500 feet from the edge of the proposed crater.

If the soldiers were U.S. military, I suspect there would be a cacophony of voices raised in righteous anger about the desecration of hallowed ground, and historical heritage and all that. But no, the warriors were Apache. The copper mining company insists that they respect the Native American heritage, and they make all kinds of public relations noise, but a great many local tribes and nations are deeply opposed to the operation.
I'm okay with weighing the pros and cons of a project like this, assuming that all parties are heard, and their concerns dealt with. But there has to be a willingness to say no, that some places should not be destroyed for the sake of profits over all other factors. I'm disturbed when those with the money are the only ones heard in the discussion and that there is an assumption that it will go forward no matter what. But ultimately politics requires a fair and open vote in Congress. And that's where the problem lies. The project will require a land swap that gives up federal land for "ecologically sensitive" lands elsewhere. And Congress has turned it down a number of times.
So in a bit of bipartisan corruption, the land swap was placed in a piece of legislation, the National Defense Authorization Act (NDAA) that had to be passed in 2014. It was a betrayal of trust on the part of people like Senators John McCain and Jeff Flake (speaking of corruption, Rep.Rick Renzi is in prison over crimes related to the land swap; and Senator Flake was once a lobbyist for Rio Tinto, one of the mine's corporate partners). This is the kind of political shenanigans that tells me that these plans need to be tabled for awhile. This isn't the way things should be done in our society.
How badly do we need this copper, really? And at what true cost?

For an excellent summary of the issues involved, please read this excellent article by Ray Sterns for Phoenix News-Times:

Saturday, January 20, 2018

A Look Back at Ten Years of Geotripping: Vagabonding on Dangerous Ground, an Exploration of Cascadia

In 2015 I wrote a blog series about driving through the "Most Dangerous Plate Boundary" in the world, but it was actually about driving through a fossil subduction zone that is exposed in the Coast Ranges, Great Valley and Sierra Nevada of Central California. In the summer of 2015, Mrs. Geotripper and I took a long journey along the entire length of a real "dangerous plate boundary", the Cascadia subduction zone, that extends from Northern California to British Columbia. The trip coincided with a media explosion over the very real possibility of a magnitude 9 earthquake along the Pacific Northwest coastline. This resulted in another blog series, Vagabonding on Dangerous Ground. Here is a compilation of the journey...

This was posted on September 13, 2015...

I've finished a new blog series on our exploration of the Cascadia Subduction Zone, so I've compiled all the posts in chronological order so you can get the story the correct sequence. Thanks for all the nice comments, responses, and corrections! Click on the orange titles for the post.

On the Road in the Pacific Northwest: The introduction and overview of the new blog series.

Following the Cascadia Subduction Zone on Highway 101: This post provided the geological background for understanding the hazards of living in the lands influenced by the Cascadia Subduction Zone.

In This Land of the Sasquatch There are Ancient Giants: The first leg of our journey took us through the range of the California Redwoods and the land of black bears that look suspiciously like walking ape-people.

The End is Coming (of the Cascadia Subduction Zone): The end of Cascadia is a slow process, but the zone is disappearing slowly, being replaced by the San Andreas fault. It's also a look at one of the loneliest beaches in California.

A Geologist Walks Onto a Bar in Cascadia: Exploring the unique baymouth bars along the Humboldt county coast.

Northern California's Tsunami Central: Crescent City has a tragic history of tsunamis, especially the one in 1964 that took a dozen lives and destroyed the marina and downtown areas.

This "Dismal Forest Prison" and other problems exploring the Northwest: The Pacific Northwest was particularly difficult to explore and map, at least if you weren't part of the indigenous culture. Here are some accounts of the discovery of Humboldt Bay by land.

Into the Land of Sand, and Exploding Whales: Between Coos Bay and Florence, Oregon, is the longest stretch of sand beaches and dunes in the Pacific Northwest. Yeah, and the whale thing...

Into the Realm of the Devil (and Sea Lions): There are a lot of things named for the devil on the Oregon coast for some reason. And some incredible sea caves occupied by sea lions.

Putting on a Happy Face at Dismal Nitch and Cape Disappointment: We reach the mouth of the Columbia River, where Lewis and Clark reached their goal. It's undergone a great many changes over the years.

Into the Rainforest, Seeing Something Strange...Rain: We explore the Hoh Rainforest in Olympic National Park for the first time, and encounter something strange, at least this year: rain. There was also a fire burning in the rainforest. That's not normal.

The Diverse Landscapes of Olympic National Park: Olympic is one of the most diverse of our national parks, with alpine glaciers, rainforests, and coastlines. It's spectacular.

The Salish Sea and the Strait of Juan de Fuca: Glaciers and tectonics combined to form a seaway east of Vancouver Island and the Olympic Peninsula. It's a unique ecosystem quite distinct from the Pacific Ocean just a few miles away.

Stone Rings, Glaciers, and "Dinosaurs" on the Coast of the Salish Sea: Desecrated burial mounds, avian dinosaurs, and glacial landscapes. Victoria on Vancouver is both a beautiful city and a fascinating place to explore.

Exploring North America's Southernmost Fjord: We take the ferry to the mainland, making landfall inside of the southernmost glacial fjord in North America, Howe Sound in British Columbia (defined here as on the mainland, but connected to the ocean; opinions differ!).

Landing Place of the Thunderbird and the Grimy One, the Volcanoes of British Columbia: Black Tusk and Mt. Garibaldi two of the northernmost volcanoes in the Cascade Range. I missed them last year in the rain, but saw them this time.

Controversial Stone People, Fire and Ice, and an Olympic Legacy: We made it to Whistler and the home of the 2010 Winter Olympics. The stone people were controversial, but the scenery was not. It was spectacular.

Seeing Volcanoes from the Inside Out at Siám' Smánit (Stawamus Chief): Glaciers and granite! Stawamus Chief is a dramatic granitic dome rising high above the end of Howe Sound. It was once the magma chamber of a volcano.

Our Tour of the Greatest National Park I Never Once Set Foot In: North Cascades National Park is a true primeval wilderness. No roads penetrate the park boundaries. But what incredible scenery!

The Geology that Explains Why North Cascades is a Park Divided: The Skagit River may be the most altered water course in the Pacific Northwest, but it provides 20% of Seattle's electricity. It splits a national park in two.

What's East of North (Cascades), A Brief Explore: North Cascades doesn't have all the scenery; the lands to the east are rather spectacular too, and offer some great geology.

Playing Hide and Seek with a Sleeping Monster: Mt. Baker is not the most active volcano in the Cascade Range, but it is capable of great mayhem. It even looked for awhile like it might blow back in 1975.

Danger Follows Us Home (As it does all of us): A Mt. Shasta drive-by (photo) shooting, and a wrap-up of the series. Danger is always with us no matter where we are. It's not to be feared, but respected and prepared for.

Wednesday, January 17, 2018

There's Always Something New to be Learned: Beavers on the Tuolumne River

I will freely cop to the fact that I am not a particularly observant person. This is quite an admission for a guy who has been blogging for ten years about geology, the science that requires skills of observation almost like no other. Still, there it is. I lived in Stanislaus County for thirty years thinking that we have maybe twenty species of birds. In the last three years of finally paying attention to such things, I've learned that we have three hundred species, including those which utilize some of the most famous wintering grounds for migratory birds in the American West (if you want to learn more about this, check out my other blog Geotripper's California Birds)

It is along similar lines that we come to my new educational experience of the day. I've been hiking the Tuolumne River Parkway Trail since before it was completed two years ago. I've documented more than sixty bird species on my near-daily hikes as well as the presence of Red Fox, Gray Fox, River Otter, Raccoon, and a troop of feral domestic cats. And yet somehow, in all of these mini-adventures, I missed some terribly obvious evidence of one other mammal along the river. Until today, when it was made as clear as the nose in front of my face...we have beavers.
I've always been aware of fallen trees along the river, but I never thought about why. But today, the cuttings were so fresh and obvious that I had to stop and look, and I did in fact see rippling in the water nearby. I may have actually interrupted the beaver at work (although they generally work at night). I started looking around and noticed that there were plenty of other small trees that had been felled by beaver incisors.

I had to hit the books (er, Google) to find out more. It turns out that the story of beavers in California is both muddled, and complicated. For one thing, California has its own beaver subspecies, including the California Golden Beaver, Castor Canadensis subauratus. Whether the distinction is biologically valid awaits confirmation from DNA studies. There isn't a lot known about their historical distribution because as most students of history know, the beaver was eradicated over much of its range by fur trappers in the early 1800s. It was assumed by some that they never inhabited the High Sierra, although some research has indicated that they did. They may have originally ranged across the entire state except for the deserts, and even there they survive today along the Mojave and Colorado Rivers. In any case, it is thought that by the 1940s there were as few as 1,300 of them left, almost all in the Great Valley. At that time, the Department of Fish and Game decided to transplant some of the beavers into some of their former range. At this point I had another surprise: some of the transplants were taken from the Tuolumne Waterford, the very spot where I was seeing beaver sign for the first time!
Beavers can be pests, especially in places like the delta of the Sacramento/San Joaquin Rivers, where they can cause severe damage to artificial levees. On the other hand, beavers can be highly beneficial in natural (or re-established) riparian habitats. Their dams help to slow down river erosion and allow more water to percolate into the ground. They tend to cause an expansion of the riparian woodlands by widening the area where the groundwater table is close to the surface.
The other small surprise of the day was the discovery that I was not the first to notice the presence of beavers (far, far from it of course). But one of the first hits on Google was that of another frequent user of the Tuolumne Parkway Trail, a naturalist, and erstwhile geology field studies student Siera Nystrom, who has taken several of my courses. Check out some of her excellent writing at Natural History Journal. Whatever I see and get excited about, she probably has seen it first! Being observant is a powerful skill to have.

Tuesday, January 16, 2018

A Look Back at Ten Years of Geotripping: Driving Through the Most Dangerous Plate Boundary in the World

Driving through the most dangerous (kind of) plate boundary in the world is actually not very easy to do. Subduction zones, with the exception of the volcanoes, are mostly deep under the sea. But Central California is a unique case, being an ancient subduction zone that has been uplifted and exposed by erosion, so that interested parties can literally drive through what once was miles underground or at the bottom of the deepest oceans. I got the idea for this blog series when I spent an afternoon driving the winding road that travels over the Coast Ranges at Lick Observatory, and down through Del Puerto Canyon into the Great Valley. It's the equivalent of driving twenty or thirty miles into the Earth's crust. Looking back over the titles, I'm worried that I am using up my lifetime supply of bad jokes...

I've been reviewing the archives this week to find some of my favorite posts from ten years of geoblogging. This compilation appeared on July 4, 2015.

Without a doubt, subduction zones are the most dangerous plate boundaries on the planet. Divergent plate boundaries produce earthquakes and occasional volcanoes, but nothing on the fearsome scale of the calderas and stratovolcanoes and magnitude 9 earthquakes experienced at convergent boundaries. Transform boundaries produce earthquakes, but they are magnitudes smaller than those produced at convergent boundaries (despite what certain Hollywood movies have asserted recently). Hot spots, while not a plate boundary, can produce huge caldera complexes like Yellowstone, but such monsters have not had much of an effect on human history of the last few thousand years. It is the subduction zones of our planet that have caused the most human misery, in the form of massive earthquakes, tsunamis, and violent volcanic eruptions.
We have been driving through an example of one of the most dangerous plate boundaries in the world, but our particular example has been inactive for a very long time. Central California was a subduction zone complex for more than 150 million years, primarily during the Mesozoic era, but it changed into a transform boundary only a few tens of millions of years ago. The San Andreas fault is the resulting feature, and it is capable producing damaging earthquakes, but even the most destructive quakes, like 1906 in San Francisco (death toll 3,000), is but 1/30 of the energy of a magnitude 9 quake like that of Indonesia in 2004 (where the resulting tsunami killed 200,000 people).

It's taken a couple of months to work through our journey, so I've compiled all of the posts here so one can catch the continuity of the story. Here goes...

A New Blog Series
The introduction to the new series, a geological transect from the California Coast to Yosemite Valley, crossing an ancestral subduction zone that once caused geological havoc in a zone from Mexico to Canada (and still is in a few places).


An overview (in the most literal sense) of the lands we will traverse on our journey. We have a look at central California from above.

These Rocks are All Wrong!
Granite is exposed in the rocks of the Point Reyes Peninsula. But the arrangement of rock and sediment in subduction zones suggests that granite shouldn't be anywhere near here. It's the San Andreas fault. In California, it's always the San Andreas' fault.

Looking for the Big One
The peace and serenity of Tomales Bay belies a violent past. The San Andreas fault slices right through the bay, and produces large earthquakes with disturbing irregularity. The epicenter of the San Francisco quake in 1906 was not far from here.

Welcome to Geology's Junk Drawer
The Marin Headlands began as a giant collector of geological flotsam and jetsam from the crust of the Pacific Ocean. The jumble of rocks accumulated in an accretionary wedge, and were later lifted up into the mountains of the Marin Peninsula.

Geology's Junk Drawer on the Marin Headlands
Exploring the hidden corners of the Marin Headlands, we find Redwood forests, beautiful views of San Francisco, and disturbing reminders of World War II.

Terra Fatale on the Marin Headlands
Although the subduction zone that formed the rocks of the Marin has been extinct for a long time, there are still plenty of hazards remaining in the region, both geological and nautical. The Point Bonita Lighthouse has been present in one form or another for 160 years. It hasn't always worked, as there are upwards of 300 shipwrecks in the area. There are other hazards too.

The Alien Bursts Forth in the Diablo Range!
We head across San Francisco Bay and start an arduous journey through the Diablo Range. The range formed as an exotic (read "alien") terrane pushed upwards through the sediments of the Great Valley Group, piercing the surface and rising into the sky. John Hurt would no doubt approve...

Exploring the Belly of the Beast in the Diablo Range
We make the first part of a long drive through a rugged portion of the Diablo Range, one of the largest sub-ranges in the Coast Ranges of California. Along the way we cross through two exotic terranes of rocks that had been carried miles deep into the crust in the accretionary wedge of the subduction zone.

At the Portal of Hell in Diablo Range
Making our way down Del Puerto Canyon in the Diablo Range, we do the equivalent of traveling through the crust of the Earth all the way into the mantle, finding outcrops of peridotite and dunite, rocks containing the mineral olivine among others. For the mercury miners, this truly was a portal to Hell.

Exploring the Ocean Crust without Unobtanium
Del Puerto Canyon cuts a swath through the Coast Range Ophiolite, the remnants of the ocean crust that once lay at the bottom of the Pacific Ocean. Though mostly in private ownership, the canyon is one of the most scenic in the Coast Ranges, and a pair of county parks in the upper reaches invite exploration.

Into the Realm of the Drowning Dinosaurs
Sediments accumulated in a deep trough along the west coast of North America called a forearc basin for upwards of 100 million years. The layers reached a depth of 5 miles! In those waters swam mosasaurs (yes, like in the recent Jurassic World movie, but they forty feet long, not a hundred), plesiosaurs, ammonites, and occasionally a drowning dinosaur. The first discovery of a dinosaur in California happened here in 1936.

The Sea Floor that became the Greatest Agricultural Region on Earth
The American Serengeti is a vast plain 400 miles long and 50 miles or so wide that once was the sea floor. The grasslands of the Great Valley once supported millions of migratory birds and grazing animals. It still supports millions of organisms, but these days, those organisms are humans. 95% of the original prairie has been developed for agriculture and the region produces a quarter of the nation's produce. And all of the almonds and walnuts.

In the Pleistocene, a Different Kind of Danger
The Great Valley would have been a most dangerous region for a different reason in the Pleistocene. Among the great herds of grazing animals there were predators, and they were adapted to bringing down giant prey, not the small game we find today. Gigantic Short-faced Bears, Saber-tooth cats, American Lions, Jaguars, and Dire Wolves.

The Dr. Who of Mountain Ranges
At least three Sierra Nevada ranges have existed throughout time. They might have even once been higher than today. The distorted deformed metamorphic rocks tell the story of the earlier ranges.

A Gentle Landscape Belies a Fiery Past
The Valley Springs formation, exposed throughout much of the Sierra Nevada foothills region, forms gentle grass and oak covered slopes, but the rock is made of volcanic ash that originated in monumental explosions millions of years ago. The ash came from gigantic calderas, some of which were hundreds of miles away in central Nevada.

A Landscape Buried in Hot Mud, and a 6-foot Long Saber-tooth Salmon

A lot of volcanoes in the world are made of mud. Lots and lots of mud. But this mud formed in violence. The Mehrten formation of the Sierra Nevada has other surprises too: gigantic tortoises, and six-foot long salmon...with fangs...

A Tale of Two Subduction Zones
There have actually been at least two subduction zones in California. Remains of the older one still make up the rocks of the Sierra Nevada Mother Lode, and those rocks were the source of gold in the Gold Rush.

Exploring the Underside of the Volcano

We wrap up the series in the heart of the ancient magmatic arc: Yosemite Valley. Walking among the towering cliffs, we are reminded that the rocks were actually formed within the magma chambers of volcanic systems, perhaps similar to Lassen Peak, Mt. Shasta, or even at times, Yellowstone.

Monday, January 15, 2018

A Look Back at Ten Years of Geotripping: I toured a marble quarry on Vancouver Island; It's almost as if they didn't want us to see the rocks.

I've been digging through the archives of Geotripper on the occasion of my tenth anniversary of geoblogging, looking for some of my favorites. In 2015 I spent a lot of time in the Pacific Northwest, resulting in several blog series, but a favorite moment was my tour of this "quarry" which some of you may recognize as something else. This blog appeared on July 13, 2015...

So, I'm out on Vancouver Island, British Columbia, enjoying my vacation with Mrs. Geotripper, and we're casting about trying to figure out what to do on this 300-mile long island. I'm doing some reading and find out that there is this place called the Saanich Peninsula Marble Quarry that offers tours. That sounds great to the geologist in me, so I talk Mrs. Geotripper into checking it out. It turns out that when you are touring an island that is mainly rainforest, rock exposures are in short supply.
I figure that a rock quarry isn't going to have a whole lot of visitors on a given day, so imagine my surprise when we reach the end of the road, and find out that the place has a parking lot, and charges admission! It was pretty steep, too, about $30 Canadian for each of us. But hey, it's rocks, and I haven't seen a lot of rocks on this trip. We pay and go on in. I'm astounded by how many people are here for the tour of the quarry.

I did some research on the rocks. The marble of the Saanich Peninsula is part of the Wrangellia terrane, rocks that formed far out in the Pacific Ocean during the Triassic Period. Around 100 million years ago during the Cretaceous Period the rocks plowed into the west coast of North America and became part of the continent. The rocks were originally limestone that formed in coral reefs and along tropical island beaches. The heat and pressure of the collision with North America caused the rock to recrystallize into marble. Today it is called the Quatsino formation.
So I follow the map, my anticipation rising as we reach the edge of the quarry, and I looked in. I was kind of shocked. There was vegetation everywhere! There was barely any rock to be seen at all! I did notice the smokestack from the smelter almost hidden in the forest beyond the quarry. How could they let this happen? Didn't they care enough to keep the rock exposed for us geologists? 
The hundreds of people around me didn't seem to mind all the vegetation. As far as I could tell, they were actually paying more attention to the flowers and stuff and pretty much ignoring the rock. I was a little confused. But at least the people that run the place have a sense of history. They put up some interpretive signs that showed the raw beauty of the rock before all the vegetation was allowed to grow over it.
The quarry was active from the late 1800s to around 1905 or so. I guess in this temperate rainforest environment the plants can take over pretty quickly. I was kind of surprised by how colorful the flowers and other plants were. I thought that at this latitude, the species diversity was on the low side. I guess not.
I finally found some rock exposures at the lower end of the quarry. The flowers hadn't yet covered everything. Water had filled the lowest part of the quarry, and I guess they were using a fountain to aerate the water or something.
It's almost as if they were ashamed of the rocks. Look at the picture above to see how the plants covered almost every part of the marble. I just didn't get it. In any case, we finished up our tour and found some gelato being sold at a stand in what looked like an old mansion of some sort, so we had a bit of dessert before heading back to Victoria.
So what did I think about the marble quarry tour? I was surprised by how popular and expensive it was, and how easily the visitors were distracted by the vegetation covering all the rocks. The pathways were well done, and there were lots of interpretive signs showing the glory of years past when plants didn't cover every rock, so one got a sense of history, and of loss. On the whole, it wasn't too bad, especially if you like plants and stuff like that. I don't recommend bringing a rock hammer. They got pretty upset when I starting taking rock samples.

If you want to check it out, don't go by the old name of Saanich Peninsula Quarry. They changed it, I guess when it got all overgrown. Nowadays the place is called Butchart Gardens.
The glories of the old days before plants covered everything.