Carlsbad Caverns

I’ve been in two very spectacular caves before in the western US: Lehman Cave at Great Basin National Park, and Oregon Caves National Monument. Both had ornate features of various shapes such as stalactites and drapery, precipitated inside the caves slowly over countless years. However Carlsbad Caverns, by its palatial size and seemingly endless collection of geological treasures, is in a league of its own. 

The extensive caverns hundreds of feet below the surface are the main attraction of this smaller national park in southern New Mexico. The park rests on the rim of an ancient limestone reef from the Permian Era (251-299 mya) that once encircled a shallow sea in southern New Mexico and northern Texas. (Guadalupe Mountains National Park in northwest Texas is part of this same reef system.) That limestone setting provided the geologic and chemical ingredients for cave formation.

Map of the ancient Permian limestone reef system that includes present day Carlsbad Caverns at left (source) and the natural entrance to the caverns at right.

I took the self-guided tour to view the publicly-accessible caverns, entering at the “natural entrance” and spent over three hours underground, amazed at the size, variety, and sheer number of formations. These formations included stalactites, stalagmites, columns, drapery, and other features, each given different names. 

Stalactites and stalagmites.

The “Big Room” is immense and itself can take well over an hour to view at a leisurely pace. There were several pools underground too and I was particularly drawn to these including one called “Mirror Lake”. Drops of water falling from above kept sending ripples through the pool. Of course naturally all of these features would be hidden to the human eye in complete darkness, but the Park Service carefully uses dim lights throughout the cave system to highlight features.

Features in the Big Room.

The main caverns are apparently only one of over a hundred caves that have been discovered so far in Carlsbad Caverns National Park. Discovery and mapping of caves continues. There is more to the park than the caverns themselves – as amazing as they are – and in the next blog post I’ll feature some of what I observed while backpacking into the park’s wilderness.

This large column has been named "Rock of Ages".

Other types of formations in the caverns. At right is a formation termed "popcorn", although this type more reminds me of a coral reef.

Formations reflected in the water at "Mirror Lake".

Another pool with formations. The faint green color is due to algae, which apparently will grow eventually hundreds of feet below ground if a dim light source is available.

An area termed the "Boneyard" by earlier explorers.

A ladder from earlier exploration in the 1920s (left) and a view of Lower Cave from the main caverns (right).

More stalactites.

Perhaps some 800 feet directly below the Visitor's Center there is almost an underground city where there are bathrooms, vendors and this mail drop. Elevators lead to the surface. Though I walked in via the natural entrance gradually descending into the caves, I took an elevator up (here photographed at 250 ft below ground).

The Great Basin

The Great Basin region of the United States is a series of alternating mountain ranges and wide valleys stretching across Nevada and western Utah. The mountain ranges run north to south, breaking up the monotony of the Nevada landscape. The alternating mountain ranges and valleys formed through a process of faulting and stretching of the crust.

I confess to seldom thinking of Nevada as a place to explore as a naturalist. It has long seemed a place to just pass through while en route to more interesting destinations. However, in my first trip across central Nevada from the Sierra near the Tahoe region to Great Basin National Park in the western reaches of the state, I was stuck by the unexpected beauty of the landscape.

Heading west to east, the parallel ranges of mountains seem to have become increasingly attractive. The Toiyabe and Egan ranges in central Nevada in particular were notable. Most of the ranges are still wearing crowns of snow which add some vibrancy to the earthen tones of the landscape. Junipers became more frequent towards the eastern part of the state, forming pygmy forests at higher elevations.

Sand Mountain (left) and the Egan Range (right).

Traversing Nevada, I stopped only briefly at places, to photograph the mountains and look at weathered petroglyphs off the highway. US route 50, which winds through the basins and ranges is proudly advertised as “the loneliest road in America”.

Approaching the eastern edge of Nevada, the bright white Wheeler Peak came into view from the previous range to the west. At over 13,000 ft elevation, it forms the centerpiece of Great Basin National Park, an oasis of forest and snow. The main entrance to the park is on the eastern side, nearly in Utah. There, Lehman Creek runs off Wheeler Peak towards the lowlands.

Great Basin National Park, as viewed from near Sacramento Pass.

 Yesterday evening I hiked along part of the trail that follows the creek up the slopes of the mountains. There, at about 8000’, was a fairly dense forest that reminded me superficially of the forested Cascades, though the main conifer species differed. Single leaf pinyon pines (Pinus monophylla) was the dominant species, joined by at least two other conifers: Rocky Mountain fir, and Engelmann’s spruce. The most attractive trees to me were not the conifers, but white-barked hardwoods, still leafless, which I think are probably quaking aspens (Populus tremuloides). Their white or grey trunks (sometimes taking on greenish or orange hues), stood like skeletons, waiting to be clothed again with new leaves for another growing season.

Populus trees at about 8000 ft elevation near Lehman Creek.

According to the Park Service ranger, this is the most
iconic feature of Lehman Caves and is known as the
"parachute". It combines several types of formations
including "shields" (at top), "drapery", and "columns".

This morning I availed myself of perhaps the main attraction of the park, Lehman Caves. Following a guide for an hour and a half, our group walked through narrow passageways and larger chambers, observing thousands of limestone sculptures, each slowly built over hundreds or thousands of years and each unique. There is an entire geologic vocabulary for the major shapes formed by the precipitates, names which include columns, drapery, soda straws, shields, and popcorn. In the array of formations, Lehman Cave was much like the Oregon Caves that I visited last summer.

After the undulation of the Great Basin, I am off to the Colorado Plateau.

References

Kauffman ME. 2013. Conifers of the Pacific Slope. Backcountry Press, Kneeland, CA.

Little EL. 1979. Forest trees of the United States and Canada, and how to identify them. Dover Publications Inc., New York

"Soda straws" on the ceiling of the cave. All stalagtites start their existence as soda straws.

More "drapery" from the cave.

Single leaf pinyon. Along with juniper, this species
was very common in Great Basin National Park.

Oregon caves

Valley leading up to Oregon Caves
National Monument.

The Oregon Caves National Monument lies in the Siskiyou range, a mountainous region in southwest Oregon rich in biodiversity.

Dozens of chambers and tunnels connect the caves in a complex underground maze discovered by Elijah Davidson in 1874 while in pursuit of his dog and a bear that had entered the cave. The caves became a popular attraction; today the National Park Service leads tours of a little over an hour through much of the cave complex.

"Drapery" formed by sheet flow of water though
the cave.

The caves formed over the course of thousands of years as weak carbonic acid slowly dissolved the marble rocks underlying the mountain. The acids formed from the interaction of water with carbon dioxide released from decaying plant matter in the soils overlying the bedrock. The caverns and tunnels vary in size and shape. A very small stream (named the “River Styx”) runs through a part of the cave complex.

Slow mineral deposition over time as water continues to move through the caves has resulted in a variety of interesting forms inside many of the rooms. Dripping water creates forms such as stalagmites and the thin “soda straws” that project from some of the cave ceilings. Flowing sheets of water over rock surfaces form other shapes such as “drapery”. Lights set up by the Park Service help illuminate many of the features for visitors. 

Other cave features: stalagmites, stalactites, and
columns (fused stalagmites + stalagtites).

Drapery is most ornate in the "Paradise Lost" room,
my favorite place along the tour route.

Other reference

National Park Service educational materials

Shasta!

I went to northern California this week for a retreat of sorts and didn’t plan to have a nature adventure. However, by northern California the sun had burned away the dreariness of the Northwest and there was a beautiful crisp blue winter sky … and Mt Shasta! This majestic mountain, full of bright white snow loomed in a cloudless sky. I’ve passed Mt Shasta many times and long been impressed at it’s stature – a mountain over 14,000 feet and the second tallest peak in California, only a bit behind Mt. Whitney. It is almost the southern-most of the Cascades, the volcanic range of the western US.

I briefly explored the juniper-covered slopes on the northern side of the mountain, including Pluto’s Cave, a wide-mouthed, dank depression set in the volcanic landscape. The junipers were not really shrubs, but more like full fledged trees. They dominate an interesting landscape in this part of northern California, dry habitat that is a little western finger of the Great Basin (Baldwin et al. 2012). I didn’t take a close look at the trees, but based on their height and the bluish berry-like cones I observed on one tree, at least some may have been Juniperus occidentalis, one of 5 species of junipers in California (Baldwin et al. 2012). As I continued south in the late afternoon, the valley darkened but Shasta kept glowing, the pure white of the mountain turning to a golden pink.

Reference:
Baldwin et al. 201.2 The Jepson Manual. Vascular Plants of California. University of California Press.

Western pearls

The Cascades and Sierras are like a string of pearls lying from north to south along the western edge of the United States: Mt. St. Helens, Mt. Hood, Crater Lake, Mt. Shasta, Tahoe, Yosemite, Sequoia. Over the last few years I have come to love these beautiful mountains. The white peaks of the Cascades are volcanic in origin and still active: the violent eruption of Mt. St. Helens in 1980 and the bubbling sulfurous mudpots found in Lassen National Park attest to this. Many of these mountains have a beautiful conical shape, like the revered symmetry of Mt. Fuji in Japan.

Mt. Lassen in northern California is the southernmost major peak of the Cascades. But topographically at least, the mountains continue to the south with the Sierra Nevada range. The Sierras tell a different geologic story than the Cascades. Some 250 million years ago, the collision of the Pacific and North American plates melted rock that formed under the ocean in plumes (1). These structures fused. Then about 80 mya, this massive chunk of rock pushed up through the ocean floor and carried the marine sediments that had been deposited on top. Asymmetrical uplift left the eastern side of the Sierras at a higher elevation, with a more gradual decline to the west. Subsequent erosion removed much of the marine sediment, and recent glacial activity carved elegant designs into the landscape such as the world-famous Yosemite Valley.

John Muir, the poet laureate of the Sierras, termed these magnificent mountains “the range of light”. In evangelical exuberance, which Muir used without hesitation in his description of wilderness, he described a view of Yosemite in the heart of the Sierras:

“It is easier to feel than to realize, or in any way explain, Yosemite grandeur. The magnitudes of the rocks and trees and streams are so delicately harmonized they are mostly hidden. Sheer precipices three thousand feet high are fringed with tall trees growing close like grass on the brow of a lowland hill …. Waterfalls, five hundred to one or two thousand feet high, are so subordinated to the mighty cliffs over which they pour that they seem like wisps of smoke, gentle as floating clouds, though their voices fill the valley and make the rocks tremble. … The mountains, too, along the eastern sky, and the domes in front of them, and the succession of smooth rounded waves between, swelling higher, higher, with dark woods in their hollows, serene in massive exuberant bulk and beauty, tend yet more to hide the grandeur of the Yosemite temple and make it appear as a subdued subordinate feature of the vast harmonious landscape. Thus every attempt to appreciate any one feature is beaten down by the overwhelming influence of all the others.” (2).

Just before the turn of the new year this winter, we took an adventure north to south down the eastern side of these magnificent mountains. We crossed the Cascades east of Eugene and once over the crest of the range, traveled from that point forward in high country on our trip to southern California. Passing through the Cascade Range in central Oregon, I was amazed once again by the dramatic shift in vegetation on either side of the divide. Dense coniferous forests with lush green understories dominate the western slopes of the Cascades, but the forests quickly change to drier, shorter and more open canopies vegetated by pines to the east. The change in forest type is, of course, driven by differences in precipitation on the eastern and western slopes. Storm clouds moving inland from the Pacific run into the mountains and dump most of their captive water before reaching the high country.

On this trip, it snowed briefly in southern Oregon near Chemult, but the skies lightened as we moved further south towards the Oregon/California border. In Modoc County (NE California), we entered the Great Basin floristic province. Here the vegetation became desert scrub peppered with juniper trees, the largest plants on the landscape. Small patches of snow remained on the ground. Our first significant stop was Lava Beds National Monument. The short winter day was drawing to a close but we explored two of the lava caves. They were cold wide shafts filled with rubble of very bland grey and pale colors; the caves relatively gradually descended downward into the earth. We saw no bats or other wildlife in the caves, but located some small ice sculptures adhering to the rocks below. The little sculptures were shaped like hemispherical ice cream scoops, having accumulated when water dripped from the cave ceiling above and apparently froze quickly as it flowed down the mound.

Visitors in a cave at Lava Beds National Monument

The next day, further south, the highway took us near Susanville and into Nevada for a time before crossing backing into California. We arranged for a stay in the small town of Bridgeport back on the California side of the border.

On day three we learned from a highway sign that several of the roads that traverse the Sierras that are typically closed to traffic during the snowy winter months were still open at this late season. This exciting news led to a quick decision to make a detour into the eastern end of Yosemite National Park. Access to Yosemite high country by car at this time of year was a real treat since National Park records indicate that Tioga Pass had not been open this late in the winter for at least the last 31 years! (3) Already at about 7000 ft elevation in the Mono Lake area, we made it up the pass to nearly 10000 ft towing our small rented trailer. Tioga Pass is a lightly vegetated gorge of granite and snow with strong winds that move down the canyon. On the less sun-exposed places to the south and deep in the canyon, ice froze in place to form suspended white and turquoise waterfalls.

Tioga Pass

At the top of the canyon, we encountered our first alpine lake (Ellery Lake), locked frozen into the mountains at 9538 ft. Further west into the park, we explored Lembert Dome, Tuolumne Meadows and Tenaya Lake. Near Lembert Dome, we took a hike through coniferous forest to Dog Lake. Like the other alpine lakes, this one too was frozen. We walked and shoe skated over the whitish-grey ice.

Dog Lake

In the afternoon we left Yosemite, heading back down Tioga Pass onto the east side of the Sierras in time for a sunset that painted clouds and mountainsides various colors. On day four we moved further south into the Owens Valley and started to encounter classic southern California desert habitat. Tufts of dried tumbleweeds were interspersed semi-regularly on sands and rubble on the grey landscape. Perhaps their phobia for neighbors was created by intense competition underground for the sparse water available in the desert. Here the landscape was open. Expansive smooth valleys were rimmed with tall mountains. The majestic granitic Sierras, light with snow cover rose, abruptly to the west from the valley floor. 

The Sierras from Owens Valley (Mt. Whitney is in there somewhere...)

The last day of our journey took us to Death Valley National Park and further south to the metropolitan expanse of southern California. Coming up towards the park, we saw Joshua tree sentinels on the landscape. We did not proceed deep into the park, but did drive through the Panamint Valley, an utterly barren swath of land set between the Argus Mountains to the west and the Panamint Range to the east. Though not hot on that late December day, one could easily imagine the searing heat of the landscape during the death days of summer.

Notes:

1. A concise history of Sierra geology.

2. Muir, J. 1911. My First Summer in the Sierra.

3. The road was finally closed on 17 Jan 2012. See the NPS data here.