Monday, October 24, 2016

The Hawai'i That Was: Rising Out of Depression on Kaua'i, and Sleeping Giants

There's a different part of Kaua'i, one that doesn't quite fit the image of dramatic high cliffs plunging into the sea. It's a lowland, a region of lesser hills and ridges that only rise a thousand feet or so, covered largely by rainforest. It's unusual because Kaua'i is often imagined as a single deeply eroded volcano that should have been evenly eroded from all directions. It turns out to be far more complicated than that. In fact, it can be thought of as two shield volcano complexes, one of which developed on top of another.
The head of the Sleeping Giant (and a tough short climb)
Nounou Ridge rises above Kapa'a and this lowland area called the Lihue Depression. The ridge is composed of the volcanic flows of the older shield, the Na Pali basalts, that date back to between four and five million years ago. Strangely, the basin below has younger rocks, the Koloa Volcanics, which date to between 2.65 million and 150,000 years ago. Why strange? If this basin were hollowed out by normal erosional processes, the rocks in the basin would be expected to be older.

The story involves the destruction of a portion of the original shield volcano that built up the island. Shields are huge volcanoes with gentle slopes, but they are inherently unstable. As has been noted in some previous posts in this series, huge avalanches sometimes cause portions of the volcano to slide into the sea. On Kaua'i, it appears that a large failure caused the eastern side of the island to subside several thousand feet. This formed the low depression, which was later covered by basalt flows of the Koloa Volcanics.

A decade ago, I climbed Nounou Ridge. A delightful trail climbs the flank of the mountain from a neighborhood above Kapa'a, offering some incredible views across the eastern part of the island.

Nounou Ridge is also called the "Sleeping Giant", and the ridge does indeed resemble a reclining big person. The story goes that a friendly giant help islanders with construction of heiaus and other structures. Celebrations followed, and the giant had too much to eat and grew drowsy and laid down for a nap. A very long nap (we've all been there, right?). I've seen stories that note that islanders started fires behind the ridge to highlight the profile in order to scare off potential invaders sailing in from offshore.

The mountain ridge in the distance in the picture above is Anahola Ridge, which like Nounou is composed of the older Na Pali basalts. If that steep pinnacle looks just a little bit familiar, think back to the memorable opening sequence of "Raiders of the Lost Ark".

The trail is mostly an easy climb to a picnic shelter on top of the "chest" of the giant. If you want to get to the high point, the "chin", you've got a bit of a climb ahead. The route (not exactly a trail anymore) is a scramble with a fair amount of exposure on both sides. I did the climb in ignorance (Read a field guide? Nah...), but I was glad to reach the summit. The view was outstanding.

The full extent of Anahola Ridge was visible off to the north, as well as the low country in between. The ridge is exposed to strong winds blowing off the ocean; note how the trees are bent over in the picture below.

The view to the south reveals Haupu Ridge, the memorable ridge that is viewed by most airplane passengers on the approach to Lihue Airport. The lowlands of the Lihue Depression fill the foreground, as well as the canyon of the Wailua River (Wailua Falls are hidden down there somewhere).

I would have included a shot of Waialeale, but as usual, the wettest mountain on Earth was shrouded in clouds.

"The Hawai'i That Was" is a series on the geology and anthropology of the Hawaiian Islands that explores the nature of the islands prior to colonization and the changes that have taken place since. If the rate of blog posting lately, well yes, it's been a busy time. Have patience, and we'll finish our trip around the island in no time!

Sunday, October 16, 2016

The Hawai'i That Was: Hanalei, Where the Waterfalls Seem to Stream From the Clouds

Paradise is a wonderful place as long as you have something to eat...

The islands of Hawai'i are often described as paradise, but the island ecosystem that existed prior to human colonization offered little to assist in the survival of the human species. The plants and animals were highly evolved in their long isolation, and few of the native species were edible to humans.
But if anything is true of the human species, it is that the group is highly adaptable, and capable of the planning for the future. The Polynesians had colonized the islands of the South Pacific for centuries, and they had a good idea of what was needed to insure survival in a new landscape. They engineered their own future by changing the ecosystems to fit their needs.

It's unknown precisely when humans arrived at Hawai'i (perhaps between 300 AD and 1,000 AD), but it is known that those who arrived were probably well-prepared. They arrived on sea-faring canoes outfitted with plants and animals that they would cultivate and raise in the new land. They brought jungle fowl and pigs, breadfruit, coconut, banana, and sugar cane. And they brought taro, which they called kalo. The starchy root of the taro was a staple in their diet as it has been in many other parts of the world.

Successful farming of taro required large amounts of fresh flowing water, which was a problem on the Hawaiian Islands. There are only a handful of rivers of any size on the islands, and so those few were extensively altered to allow the most extensive production. Which brings us to the northern side of Kaua'i, where the Hanalei River is one of the few rivers with a floodplain large enough for kalo production. The beautiful valley is one of the largest kalo growing areas on the islands
The Princeville Resort on the north shore is sort of the "end" of the road for tourists seeking the most modern of amenities and wide smooth roads. As the highway continues into the Hanalei Valley and on towards the village of Hanalei, the road narrows. A pullout provides a stunning view of the valley and the taro fields.
The mountains of Kaua'i capture prodigious amounts of precipitation from the Northeast Tradewinds. Nearby Mount Wai'ale'ale is often described as the wettest place on Earth, with an average rainfall of around 450 inches each year. The constant rain on the exceedingly steep terrain above the Hanalei River means that waterfalls are visible much of the time (at least in my extensive experience of three visits). The water seems to stream from the clouds that are constantly draped over the mountain slopes.
The single lane bridge over the river is one place to become familiar with Hawaiian politeness (and the sometimes boorish behavior of tourists).
This blog post is part of my continuing series (off and on) about the Hawaiian Islands based on my recent field studies course on the Big Island and Kaua'i. We've been exploring the Hawai'i that once was, compared to the Hawaiian Islands since humans arrived. We're getting close to the end of the story, so I'll be trying to get the job finished in the next couple of weeks.

Tuesday, October 11, 2016

Bug Art at Beetle Rock

There is always something new to see when you are on the road. We were exploring the geology of Sequoia National Park for a field class this last weekend, and we saw many marvelous and beautiful things, but this was a new one for me.
We were at Beetle Rock, an exfoliation dome in the Giant Forest area of the park. The view was wonderful, but I noticed the oak trees at the edge of the clearing seemed "off". There was a mixture of green and brown in the foliage, and it wasn't fall colors. A closer look revealed feeding trails of some kind of insect, perhaps some sort of Leaf Miner (I would appreciate some help with identification, bug people!).
I don't know if this extensive pattern of feeding is detrimental to the health of the tree. There are a lot of changes happening in the Southern Sierra Nevada as a result of extended drought and climate change, and the number of dead conifer trees was truly depressing. I'm worried that something has also made the oaks susceptible to insect attack.
I've not noticed this sort of thing in the past, but then again, I've been known to not pay close attention to plants when there are rocks to look at. And the rock at Beetle Rock is pretty interesting. I just wasn't expecting actual beetles...

Monday, October 10, 2016

Spectacular Folds in Kings Canyon

It's just a short stop on a three day exploration of the geology of Sequoia and Kings Canyon National Parks in the California's Sierra Nevada that we just completed. But what a sight! The Sierra Nevada is known for its vast granitic rock exposures (more than three-quarters of the range), but fascinating stories are told by the other rocks too. There is a spectacular gorge along the Kings River where rocks of the Boyden Cave Roof Pendant are exposed. There are vast cliffs of marble and quartzite, and other slopes expose former mudstones and claystones of a long-vanished sea. The rocks have been buried, baked and twisted into a series of tight "chevron" folds.

The exposure is well-known to geologists who explore the region, but even though I've visited the site numerous times, I was struck by not just the folds themselves, but their setting deep in the gorge. Cliffs soar thousands of feet above, and I'm not sure why I haven't included them in the photographs I've taken in the past. It leaves me wondering how this canyon could have been left out of Kings Canyon National Park, whose boundary lies just a few miles upstream. Just downstream, Kings Canyon reaches its greatest depth below Spanish Peak, some 8,012 feet. This is just 19 feet or so short of being the deepest canyon in North America by most reports (some claim Kings Canyon is the deepest).
Here are the folds from the conventional angle from across the highway.
These rocks are part of the Kings Terrane, a section of the earth's crust that was swept into the subduction zone that once existed offshore of Central California in the earliest days of the dinosaurs (Triassic-Jurassic time). They are a great spot to demonstrate the power of tectonic activity in the shaping of the Earth. If you want to find them yourself, drive a half mile or so upstream of Boyden Cave on Highway 180 towards Cedar Grove in Kings Canyon National Park.

Tuesday, October 4, 2016

The California That Was: A Day in the San Luis National Wildlife Refuge

I've spent a good part of the last few months blogging about the "Hawai'i That Was", in which I have been exploring the bits and pieces of the original islands that existed before European/American incursion. I will even finish the series before long, but in the meantime I've been keeping up with the new semester (already a third of the way over), and the fall field trips. I had a break last Saturday and Mrs. Geotripper and I headed south to see if any of the migratory birds had arrived at our local refuges.
Tule Elk at the San Luis NWR
The first refuge, the Bear Creek unit of the San Luis National Wildlife Refuge was sort of a bust, as no water had been allocated to the pools there, but the Tule Elk autotour a little farther south afforded some neat photo opportunities. A huge Tule Elk buck rose out of the grassland, and I was suddenly reminded that there is a "California That Was" as well. I live in a huge prairie, the Great Valley of California, and even though most of it (95%) has been consumed by agricultural and urban development, there are still some pieces left here and there where one can be reminded of what a treasure this valley truly is (or was).
Can you see why I took this picture?
The prairie grasslands extended for four hundred miles from present day Bakersfield to Redding, and the valley averages forty or fifty miles across. Although it receives rainfall equivalent to a desert in the southern portion, rivers draining the Sierra Nevada provided plentiful water, so much so that a large part of the south valley was covered by shallow lakes (Buena Vista and Tulare). Those lakes disappeared during the last two centuries as streams were diverted for agricultural development.
The valley supported a rich ecosystem that included numerous grazing species such as the Tule Elk, deer, and pronghorn antelope, and predators that included wolves, coyotes, mountain lions, and Grizzly Bears. Many of them are gone, but we were privileged to see the Tule Elk herd and a well camouflaged deer that made its way to the Salt Slough for a drink.
Salt Slough in the San Luis NWR
More than anything else, the "California That Was" was bird country. Millions upon millions of migratory geese, cranes, and ducks called the valley home during the winter months when the northlands were covered with ice and snow. The lakes, rivers, and wetlands provided food and shelter for the tired migrants. Although far less land is available to them today, hundreds of thousands of birds still spend the winter here, and that's what we were looking for on Saturday. We heard that some Sandhill Cranes had already arrived and we wanted to have a look.
Egrets and Sandhill Cranes at the Merced NWR
Hundreds of them had indeed arrived, but we were surprised by the number of egrets present in the refuge. It's strange how such birds can be clumsy looking and graceful at the same time.
Great Egret at the Merced NWR
The California prairie is perhaps the most altered landscape on planet Earth. It's nice to know that there are dedicated groups of people working to maintain some small corners of the valley for the birds and other wildlife. It's a real privilege to have a chance to see what was once here.
Sandhill Crane at the Merced NWR

Friday, September 23, 2016

The Lake at the End of the World: Tule Lake in Northern California

Tule Lake is situated at the end of the world. It's not that it's so big that the world seems to end beyond its margins, but something more like how it is the place that worlds ended. The lake is located in Northern California near the Oregon Border south of Klamath Falls. It fills a fault graben, a basin that formed when the crust stretched and cracked, with large valleys that sank hundreds or thousands of feet. The Tulelake graben sank enough to disrupt the flow of regional streams, and became a huge, but shallow lake. In this semiarid climate water is precious, especially to birds on the migratory flyway from the arctic to the tropics. It's one of the places where plentiful food allowed millions of birds to rest and fatten themselves to continue their journeys.

But it nearly ended for the birds. Settlers in the late 1800s found that streams could be diverted, and that levees and dikes could be constructed, so that vast portions of the lake dried up and disappeared. The nutrient rich sediments of the lakebed became pastures and rich soils for growing alfalfa or potatoes. In 1928, though, a wildlife refuge was established that preserves the remaining lake area for the birds and other animals. The present lake, as big as it seems in the photo above, is but 10% the area it once was.

The lake was the end of the world for a people as well. The Modoc people lived along the shores of the lake for hundreds, maybe thousands of years, but were forcibly removed in the 1870s. Many elements of their culture were lost as their community was shattered. I wrote more extensively on this sad history in a previous post. The story is compelling...check it out!

This is a dispatch from the road, some short descriptions of our ongoing field class on the geology of California's volcanoes.

Wednesday, September 21, 2016

About to Hit the Road Again! There are Volcanoes in my Future

And it's been way too long locked away in an office and laboratory and lecture hall. I'll be hitting the open road with my students on an exploration of California's Cascade volcanoes for the next five days. We'll be seeing Mt. Shasta, Lassen Peak, Medicine Lake Highland, and Lava Beds National Monument. All in all, it's a fascinating corner of the Golden State. I may actually have some web access along the way, so I'll try to send some dispatches.