Showing posts with label Pluvial lakes. Show all posts
Showing posts with label Pluvial lakes. Show all posts

Thursday, February 22, 2024

Echoes of a Watery Paradise in a Forsaken Hellscape - The Brief Return of Death Valley's Lake Manly

Imagine a lake that's six miles across flanked by dramatic mountain peaks reaching heights greater than 10,000 feet. We're in California, so it's got to be Lake Tahoe, right? But it's not. It is the lowest and driest place in North America, and the hottest place in the world. It's Death Valley. And big lakes are not a normal part of the scenery here. Badwater Basin is normally a dry salt flat. What has happened here?
In a word, it's rain. An extraordinary amount of rain has fallen in and around Death Valley this year, around 300% of what is normal. That sounds more dramatic than saying that 4.8 inches has occurred so far. A "normal" year to this point would see about 1.5 inches. And the rain did not fall in Death Valley alone. Death Valley is the lowest basin in a very large drainage system, and the surrounding landscape received even more. It was primarily the result of two events: the remnants of Hurricane Hilary in late August 2023 provided the floodwaters that resulted in the first iteration of the lake. In the hot months that followed, much of the accumulated water evaporated, but then the first week of February brought an atmospheric river storm to California that rejuvenated the shrinking lake. We were lucky to arrive a week later.

This kind of thing doesn't happen often. Some water was present on the valley floor in 2010, and earlier in 2005. But both of those years, floods had damaged the road to Dante's View so I haven't had a birds-eye view of the lake in at least three decades. It was fantastic.

When I and my students travel to Death Valley they get a packing list, but I tend not to put 'kayak' or 'raft' on that list. But we knew the lake would be there, so our long-term friend and trip volunteer Ryan actually packed one, so we had the spectacle of the Hollister family rafting Death Valley. 

The lake has been in the news, so we weren't surprised to see a multitude of tourists gathered in the parking lot at Badwater. I didn't think they'd all opt to go walking in the slimy muddy salty water, but you can see that they did. I was much happier to have stopped along the lake a mile to the south where there was no one but ourselves.

It was along that quiet shoreline that I was able to hear the echoes of a distant past when Death Valley was a watery paradise rather than the hellscape it is today (albeit a very beautiful and dramatic hellscape). That is what is revealed by the geological evidence scattered along the normally parched lake margins. 


At the south end of Death Valley there is an old basalt cinder cone with a strange name: Shoreline Butte. In the picture above, the shoreline terraces are highlighted by the "Superbloom" of 2016 (with all the rain this year, there is at least a possibility of another superbloom in a few weeks). Each of those horizontal terraces was carved by wave action. This and other clues scattered around the margins of the basin are evidence of a lake that existed here for thousands of years. It was as much as 600 feet deep, and more than 100 miles long. 

Where did all that water come from?

Along Beatty Cutoff Road, there is a beach berm covered by rounded flattened pebbles. This was along the northern shoreline of Lake Manly when it was 450 feet deep.
Evidence suggests that Lake Manly existed during a period from 186,000–120,000 years before present, dried up, and then returned again between about 35,000 to 10,000 years ago. It can't be a coincidence that these dates are identical to the dates established for the Tahoe and Tioga stage glaciations that took place in the Sierra Nevada. No glacier ever reached Death Valley, but the Sierra glaciers contributed vast amounts of meltwater to the dry basins east of the mountains. These waters filled present-day Mono Lake to overflowing. It spilled over and flowed in the Owens River to Owens Lake, which actually persisted into the modern era when LA water diversions caused it to dry up in the 1920s.

Pluvial lakes of Eastern California. Source: Philip Stoffer of the U.S. Geological Survey

Ice-age Owens Lake reached a depth of 300 feet and spilled over into China Lake, then Searles Lake, Panamint Lake, and finally Lake Manly in Death Valley. These ice-age bodies of water are called pluvial lakes. The cooler wetter conditions allowed two other river systems to contribute water, the Amargosa River out of Nevada, and the Mojave River out of the San Bernardino Mountains in Southern California. There may have even been a temporary connection with the Colorado River, which resulted in one of the most surprising aspects of Death Valley biology: fish!

Salt Creek Pupfish from the middle of Death Valley

Yes, there are fish in Death Valley! In fact, there are several species. They survive in widely scattered springs and short stretches of perennial streams that exist in the desert. The pupfish (cyprinodon) are of particular interest because they probably once were a single widespread species, but when isolated in springs that were either hot or cold, or salty or fresh, they were forced to evolve or perish. Today there are four species in the confines of the park and several others in outlying areas, especially the Owens Valley and Ash Meadows in Nevada. I've found their story to be intriguing and I've written about them a number of times. These diminutive fish survive in the saltiest and hottest water of any known fish species.

Mammoth bones on display at the Shoshone Museum, east of Death Valley

Imagining this vast ice-age lake meant led to another vision of past worlds. In the early 1980s, some students on a geology field trip were hanging out near their camp in the Shoshone area when they discovered bones sticking out of a gully wall. These bones proved to be specimens of Columbian Mammoths and other ice age mammal species (the specimens are currently on display in the Shoshone Museum east of the park). The Death Valley region was a much cooler and more verdant environment during the ice ages, and the shoreline of Lake Manly was populated by grazing animals including the aforementioned mammoths, camels, horses, bison, and the carnivores that would have preyed upon them, including the large cats and perhaps relatives to today's wolves and coyotes.

Looking at the shore of Lake Manly at Badwater from a vertical mile above from Dante's View
To see a lake that only comes into existence every decade or so is a spectacle (in the best sense). But to understand the deeper implications suggested by these lakes that speak of past worlds is the magic of geology. See it if you can. It won't last much longer!

Saturday, February 23, 2019

What's the Most Alien Landscape You've Ever Explored? Here's a Candidate

What is the strangest landscape you've ever explored? That is, the kind of place that makes you think that this just isn't part of planet Earth. I got to experience one of those places last week during our field studies trip to Death Valley National Park.
Only this bizarre landscape is not in Death Valley National Park. It's part of the California desert southwest of Death Valley in the Searles Lake valley. It's not part of any national or state park. It's administered by the Bureau of Land Management as an Area of Critical Environmental Concern and more recently as part of the California Desert Conservation Area.
The Bureau of Land Management has always had an uncomfortable fit with land use priorities in the American West. The Bureau began as a land disposal operation under the direction of the Homestead Act back in the latter part of the 1800s. The land that was not selected by settlers from the east was seen as sort of a wasteland of little interest to most people. But land ethics change and by the 1970s many people began to recognize that many BLM lands were every bit as precious as the adjacent national parks and monuments. This is one of those landscapes. They're called the Trona Pinnacles, and I saw them up close for the first time in my life last week.
When one realizes the richness of Death Valley National Park and all of the strange and wonderful features within, one can almost understand why I haven't been to the Trona Pinnacles before. By the time we arrive in their vicinity, we've already seen four days full of strange landscapes and on the last day we have two important geological localities and then a six-hour drive home. There just hasn't been enough time.

This year was different. We arrived at the park in midst of one of the most intense storm events of the year. Record snow and rain was falling in the coastal regions and the Sierra Nevada, but we had mostly benign conditions during our journey. But the storms caused the closure of the road that we needed to access Aguereberry Point, and construction had closed the access to Mosaic Canyon. We needed a last geological stop and I remembered how we often could see the pinnacles in the distance as we headed home. Why not see if we could get there? We headed south on the five-mile gravel road outside of Trona and had little problem reaching the pinnacles. We started exploring. I was awe-struck.
There are 500 of these pinnacles in three groups. They range in size from a few feet to more than 140 feet high, with an average of around 40 to 50 feet. They occur in three groups (the north, central, and south groups). We were exploring the north group, consisting of some 200 pinnacles. But how did they form? Are they volcanic? Are they alien landing beacons? According to the Star Trek canon, that might be the answer...in what is widely regarded as the worst Star Trek movie, The Final Frontier, the pinnacles formed the setting of the final confrontation of Captain Kirk and the "God" who needed a starship to escape his planetary prison ("What does God need with a starship").

So what really happened?
Today the bottom of the Searles Valley is a sun-blasted dry lake full of salts and other soluble chemicals that are mined on a large-scale basis. But between 12,000 and 25,000 years ago the landscape was much different. The last of the major ice ages, the Tioga, produced extensive glaciers throughout the Sierra Nevada. The Sierra rain shadow prevented many glaciers from forming in the mountains to the east, but glacial meltwater filled the basins. One by one they spilled over into the adjacent valley forming a series of large lakes: Mono, Owens, China, Searles, Panamint, and ultimately Manly in the bottom of Death Valley. These are called pluvial lakes. The surrounding valley floors sported grassy prairies and the hills had forests of trees like pinyon, juniper and at higher elevations, firs. The prairies were grazed by bison, horses, camels, and mammoths. They were hunted by Dire Wolves and Saber-tooth Cats and other fearsome carnivores.
The towers are composed of calcium carbonate, which is the mineral calcite. The porous form of calcite is called tufa. The tufa formed when calcite-rich freshwater springs on the lakebed interacted with the alkaline water of the lake. The location of the springs seems to have been guided by faults running through the area. The towers could only have formed when covered with water, so the pinnacles have been exposed to the elements for more than 10,000 years.

More recently formed towers are visible at Mono Lake near Lee Vining and Tioga Pass in the Sierra Nevada. They were still forming when Los Angeles diverted the water from streams flowing into Mono Lake in 1940. The lake began to dry, exposing the tufa towers.
The snowcapped peak in the picture above and below is Telescope Peak, the highest point in Death Valley National Park at 11,043 feet, more than 9,000 feet above the floor of Searles Lake. Such are the extremes of this fascinating landscape.

There was a lot to see in Death Valley and the surrounding region during our journey last week. More blogs will follow! And while you are waiting for the next entry, tell me about the most alien landscape you've ever seen...

Friday, February 24, 2017

A Place Where Water Once Was But Was No Longer, But Once Again Was - Travels in Death Valley

I'm finally not "liveblogging the deluge" anymore. I thought back at the beginning of January that I was monitoring a historic flood event that was going to be over with in just a few days. Somehow, new storms kept blowing through, and I was watching and monitoring flood activity around the state. Those "few days" turned into a six-week series of observations. But now that the storm activity has subsided a bit, the observations are going to be in the past tense. I didn't have much in the way of internet access over the holiday weekend, and we went and stared into the abyss of the storm with little to defend us but waterproof jackets and the nylon walls of our tents. We explored Death Valley National Park during one of its most intense storms of the year.
On the whole, we were pretty lucky. We got drenched by rainstorms on the first two nights of the trip, and rain played havoc with our travel plans during the first two days, but most of the principle roads in and around Death Valley remained open, and we were able to get to most of our objectives. The first day was certainly typical of this; we missed a planned fossil hunt because of the driving rain, but we managed stops at the other three localities, and even added two extra stops that weren't in the original plans. Our first stop was at Red Rock Canyon State Park near Mojave for a look at the colorful terrestrial deposits of the Ricardo (or Dove Springs) formation. If the exposures look familiar, you've probably seen them in a number of Hollywood movies. I've written extensively about the geology of Red Rock in the past; check out this post for some details of this fascinating place.

The real thrill of the day was to see water where water once was but was no longer, but once again was. Shall I explain?

During the Pleistocene Ice Ages between 2 million and 12,000 years ago, the climate of the northern hemisphere swung wildly from warm to cold and back to warm again, perhaps as many as twenty times. Ice accumulated across broad swaths of Canada and northern Europe, and several times crept across the border of the United States, ultimately covering around 30% of the lower 48 states. The thick ice cap never reached Oregon or California, but the Cascades and the Sierra Nevada developed an extensive network of alpine glaciers. Some streams of ice, for instance in the Tuolumne River basin, reached a length of 40 miles.
The glaciers of the Sierra Nevada never reached far into the desert basins to the east, but the influence of the cooler and wetter conditions was unmistakable. Meltwater filled the enclosed basins which then spilled over into adjacent basins, forming a series of what are now called pluvial lakes. Mono Lake is a small remnant of the glacial Lake Russell, and Owens Lake still contained water as recently as the 1920s (before Los Angeles diverted the incoming streams). Other lakes included China Lake, Searles Lake, Panamint, and ultimately Lake Manly in Death Valley. Vigorous fast-flowing rivers connected the widely separated lakes. Our second stop concerned one of those rivers, the one that flowed from Owens Lake to China Lake through the Indian Wells Valley.

From several hundred thousand years to as recently as 10,000 years ago, basaltic lava flowed from cinder cones and fissures of the Coso Volcanic Field. Some of these flows blocked the river, and formed a forty-foot high waterfall. The river scoured a channel, and the waterfall eroded in an upstream direction. Boulders trapped in river eddies swirled around, forming amazingly deep potholes. And then the ice receded. The level of Owens Lake dropped below the rim, and the river through what we call Fossil Falls ended.

The river ended thousands of years ago, but on rare occasions there is an echo of the days when a wild river flowed through the gorge. I've seen it only twice, but when the rains have been plentiful in the Owens Valley, a small stream of water flows through Fossil Falls. That's what we got to witness last week, thanks to the Bombogenesis storm (or Lucifer, or whatever they called it). A river the color of a creamy latte made its way through dark basalts.
It was a fine introduction to our exploration of the geology of the Death Valley region, and it wasn't the first time we were going to see water in places where water was not normally found. Death Valley is a place where the water once was, but was no longer, but once again was...
This last picture is kind of cheat. I didn't climb down into the gorge for a close up, so this is from 2005, the only other time I've seen water at Fossil Falls.

Monday, March 2, 2015

How Did Fish Get into the Desert of the Basin and Range Province?

Source: "Pleistocene Lakes and Rivers of Mojave" by Philip Stoffer (14 January 2004). Changing Climates and Ancient Lakes (.html). Desert Landforms and Surface Processes in the Mojave National Preserve and Vicinity. USGS, US Department of the Interior. Retrieved on 2009-09-12. - http://pubs.usgs.gov/of/2004/1007/images/glaciallakes.gif.
Following a pair of posts that mention fish in the desert (here and here), I received a comment asking where the connections were that allowed fish to make the journey from the Colorado River system into areas as isolated at the Owens Valley and Death Valley. Courtesy of Philip Stoffer of the U.S. Geological Survey, here is the map. The drainage through Danby, Cadiz, and Bristol Lakes is the probably route of numerous fish species during the ice ages. From there, they were able to move through Soda and Silver Lakes into the Death Valley-Owens River system.

It is an unexpectedly diverse group of fish. According to this report, there were 56 species and 75 subspecies of fish living in the Basin and Range/Mojave Desert provinces. Ten of these historically known species/subspecies are extinct. Another 75 are listed, are candidates for federal listing, or are species of concern. 9 out of 10 of the subspecies are endemic, meaning they are found nowhere else in the world. The fish include the highly endangered Devils Hole Pupfish, the popular Lahontan cutthroat trout, as well as a variety of dace, chubs and suckers.

The story of why they are endangered is easy to summarize. They need water to survive, and so do humans. It is the choices that humans make that will determine the future of this fascinating group of fish. The Owens pupfish (Cyprinodon radiosus) would be extinct today but for the intervention of a Fish and Wildlife officer who carried the worlds entire population (800 individuals) out of a drying pond in two buckets, and established the fish in six other localities (four of these remain). The Devils Hole Pupfish in Death Valley National Park exist today because of a Supreme Court decision halting the drilling of groundwater near the only pool in which they exist.
A Death Valley Pupfish, found in Salt Creek on the floor of Death Valley.