Monday, February 29, 2016
The Age of a Mountain versus the Age of (the rocks of) a Mountain: Arriving in Death Valley National Park
We entered Death Valley from the west, driving over the Darwin Plateau at the south end of the Inyo Mountains. Just beyond the summit we stopped briefly at the Father Crowley Vista Point, which overlooks a deep desert valley that isn't Death Valley. It's Panamint Valley, another faulted basin only a bit less deep than Death Valley itself. The setting sun highlighted the rocks exposed across the valley in the Panamint Mountains. Thousands of feet of limestone and sandstone were visible, exposing evidence of more than 100 million years of quiet deposition of mud and sand on the western margin of the North American continent during the Paleozoic Era
The earliest Hominids, had they cared to, could have seen Death Valley before it became an actual valley.
As the shadows lengthened, we crossed Towne Pass at 4,956 feet (1,511 meters), and descended the long grade to our our sea level camp at Stovepipe Wells. We had reached the actual Death Valley. Would there be geology? Would there be flowers? Stay tuned!
Saturday, February 27, 2016
I spend a lot of time in classrooms drawing cartoons. Lots of them, diagrammatically representing folds, faults and stratigraphy, trying to communicate to my students how these structures tell the story of the Earth. The problem for many of my students is that these are just cartoons. Cartoons on Saturday mornings (do ANY of you remember when that was the only time one got to watch cartoons?) do represent life in a way, but only if you have a real life to compare them to. And that's the problem for many students these days. They have no real-life experiences in the outdoors with which to compare these drawings.
And thus, the value of a field studies course. There is nothing quite like having the privilege of standing beneath a cliff, enjoying and appreciating the scenery, yes, but also being able to understand the story it tells. Our trip to Death Valley a few weeks ago included a fossil hunt at the first stop, but our second was a site where basic principles of geology stand out in stark relief, without a need for a chalkboard cartoon (I forgot the chalkboard this trip anyway). We had arrived at Red Rock Canyon State Park in the Mojave Desert. Just stepping out of the vehicles presented us a cliff face that was a physical representation of the diagram at the top of the post, a series of brightly colored layers of sand, siltstone and volcanic tuff transected by a fault.
The order of the layering provides a fine example of "superposition", the principle that layered rocks are stacked oldest to youngest, unless they have been overturned. This is one of the earliest principles of geology, described originally by Nicolas Steno in the 1600s. Looking east along the cliff we could also see the physical manifestation of another Steno principle, that of original horizontality. Most sedimentary environments produce horizontal strata (think floodplains or lakes, or shallow seas). If layers are tilted, some kind of force has acted on them, and being here in southern California, faults might be at fault.
A discussion of these basic principles was followed by a short "mapping" project. We weren't quite to the proficiency of working with maps, but the students set out to propose how they would organize the layers into formations and members that could be used to tell a logical story as to how these rocks could have come to have the structure and appearance they have today.
Red Rock Canyon does have a fascinating story as it turns out. The red and brown layers, called the Dove Springs Formation, record deposition of silt and sand in river floodplains and ephemeral lakes between 12.5 to 7.5 million years ago. The semiarid savanna environment supported a diverse ecosystem that included extinct elephants (gomphotherium), ancestral rhinos, three-toed horses, giraffe-like camels, saber-toothed cats, and bone-crushing ancestors to the bears and dogs. There are also numerous smaller fossils like ancestral skunks, alligator lizards, and shrews, with a total plant and animal species count of more than one hundred. The ecosystem suffered the occasional catastrophe as it was buried by volcanic ash. Basaltic lava flowed across the region.
Speaking of roads and cartoons come to life...here's the Roadrunner (pic is actually from Joshua Tree National Park)....
...and Wiley E. Coyote. Despite living in the most desolate driest place in North America, it looks like this one has actually caught a few roadrunners! Seriously, this coyote lives only a few miles from Badwater, the hottest and lowest part of Death Valley.
Wednesday, February 24, 2016
|The Wasco 4.9 earthquake, as recorded at Modesto Junior College|
California has been shaken by another near-magnitude 5 earthquake, and this one is a bit odd. It hit in the Great Valley, one of the few places in California NOT known for having faults and earthquakes. It occurred near the south valley town of Wasco, and had a magnitude of 4.9, along with a couple of aftershocks as high as magnitude 2.6. The first motion solution suggests right lateral strike-slip motion in the same orientation as the San Andreas fault, which lies to the west in Coast Ranges.
|Not the kind of place one expects to see fault zones...|
The U.S. Geological Survey event page for the earthquake can be seen at http://earthquake.usgs.gov/earthquakes/eventpage/ci37528064#general_region.
Tuesday, February 23, 2016
The sun dogs (also called mock suns or phantom suns; scientists call them parahelia) are caused by the refraction of sunlight through hexagonal ice crystals in the upper atmosphere. The rainbow colors in the sun dogs themselves happen because of the prisming effect of the crystals.
Either that, or I have summoned forth the twin solhundes (sun wolves) of Norse mythology...
Monday, February 22, 2016
We actually have two kinds of "snow". The other is falling off the almond trees about now, as the they bloom and set fruit. Yes, that's happening now. I left a week ago to go take a field class to Death Valley, and when I got back it seemed like the entire Great Valley was awash in white blossoms. It was a startling change.
Sunday, February 21, 2016
Thursday, February 18, 2016
|San Gorgonio and the San Bernardino Mountains from the vicinity of Idyllwild|
|Photo by Mrs. Geotripper|
The mountain range is a treasure. In my youth, I honed my hiking and camping skills in these mountains, and from them I learned to love topographic maps. It pains me that I don't have digital images of the sights I saw in these peaks forty years ago when I regularly backpacked in and out of the canyons and across the mountaintops. One of my most vivid teenage memories is a hike I took into the headwaters of the North Fork of the Whitewater River. The camp was on a terrace above the creek, and there was an expansive view eastward into the desert around Palm Springs. As the sun set, we could see thunderheads rising in the far distance, and the nighttime was punctuated with flashes of lightning. I had never felt so isolated in my life, and that is not a common feeling for the people of SoCal. It was exhilarating, and I loved every moment.
|Source: National Park Service|
|Source: U.S. Geological Survey, via http://www.livescience.com/48393-pygmy-mammoths-channel-islands.htmls|
And smaller. Eventually, a race of pygmy mammoths (Mammuthus exilis) evolved. Some of the adults stood no higher than 7 feet at the shoulder, and weighed one ton, instead as much as ten. Eventually though, even small size wasn't enough. They became extinct about 12,000 years ago.
But this post is not pessimistic. Far from it. This is about a piece of tremendously good news that came to pass this week. For years, California Senator Feinstein has been promoting the idea of several national monuments or parks in Southern California. The political gridlock in Congress has prevented anything from being done, but President Obama has used his authority under the National Antiquities Act to declare three new national monuments. Two of them are in the Mojave Desert, in the Castle Mountains, and in the landscape between Joshua Tree National Park and the Mojave National Preserve. The third, Snow to Sand National Monument, brings protection to the highest ridges of the San Bernardino Mountains to the desert floor at Morongo, and even more importantly, linking the mountains to Joshua Tree National Park. This has the effect of bringing permanent protection to a very scenic wilderness area, but even more importantly, producing an intact ecosystem that will give declining wildlife populations a fighting chance to survive, especially as our global climate warms up.
By preserving an unbroken habitat from just above sea level to 11,499 feet, there were be room for upward migration of animal and plant species as the lower levels become hotter and drier. Few places in the world offer such a range of available habitats. There is so little left, so I'm glad to see these efforts to protect such a fascinating region. The mountains of my youth!
Wednesday, February 17, 2016
|February 13, 2016|
We were in Death Valley over the weekend for our annual geology field studies trip, and one of our traditional stops is an exposure of the Pahrump Group of rock layers at the base of Jubilee Pass about twenty miles south of Badwater. The rocks record the ripping apart of the ancestral North American Continent around a billion years ago, and they are interesting no matter the season. The black hill is composed of Beck Springs formation, a dolomite deposited in a fault trough under tropical conditions. The orange rocks are the Kingston Peak formation, a rock that includes probable glacial deposits. In a tropical, even equatorial setting. These rocks record what may have been the planet's most intense glacial episode, a period when much of the Earth was covered by glacial ice (it's called the Snowball Earth Hypothesis).
But on Saturday, the hills and slopes were alive with Desert Gold and Verbena. And there were lots of green sprouts, promising even more growth in coming weeks. Officials are suggesting this might be one of the ultra-rare "superblooms" that occur over decades rather than years.
I've been privileged to see just a handful of extraordinary growth years. The only one I have digital images from was in 2005. It provides a nice comparison to what is happening in Death Valley right now. That year was a real challenge as we faced heavy rain and wind for most of the trip. The portrait below illustrates my morning observations that year. I'm thankful that we had perfect weather this last weekend.
I'm hoping to make a special trip out there in a few weeks to see how things are progressing.
Tuesday, February 16, 2016
The epicenter is just north of the Palisades Group of peaks on the eastern boundary of Kings Canyon National Park. They are the snowy glaciated peaks in the picture above. Big Pine is just to the left of the picture on the valley floor.
|4.8 magnitude main shock|
The fault that produced the quake shows right lateral strike slip motion. This means that the two sides of the fault moved sideways relative to each other, with the southwest side of the fault moving northwest. Since the Owens Valley is a fault graben, one might assume that the fault motion should have been vertical, i.e. lifting the mountains or dropping the valley, but the Sierra Nevada as a structural block is moving northwest relative to the rest of the continent, so this quake is consistent with that motion.
|Sierra Nevada as a "microplate" moving northwest. Big Pine is labeled BP. Source: http://tahoequarterly.com/Features/Story/ice-fire-and-granite|
The regional is seismically active. One of California's great historical earthquakes had an epicenter a short ways to the south at Lone Pine. The 1872 event had a magnitude estimated to be as high as 7.9. The quake killed 27 people, nearly a tenth of the population of the village at the time. Ground ruptures extended from Owens Lake to north of Big Pine.
|The 4.3 magnitude aftershock|
Our seismometer is a simple classroom instructional model (from Wards Scientific), but we get good results with local quakes of moderate magnitude, and larger quakes worldwide.
The U.S. Geological Survey event page for the magnitude 4.8 quake can be seen here: http://earthquake.usgs.gov/earthquakes/eventpage/nc72592670#general_executive
Sunday, February 7, 2016
Beauty and ugliness...
A Meadowlark is singing in the breeze...it's early February in California which actually means that spring is practically here. In other places, biplanes are spraying pesticides and fungicides, beekeepers are setting out hives in the almond groves, and fields are being plowed and readied for planting. About 95% of the floor of the California's Great Valley is being readied for crop production, with some hopes that the larger snowpack will allow irrigation allotments for the first time in a number of years.
But not here. I spent the afternoon on a deserted road that traveled around the Tule Elk habitat at the San Luis National Wildlife Refuge. Nothing human was happening here. On this old floodplain of the San Joaquin River the native grasses were sprouting bright green shoots, and the elk were grazing in the distance. The Salt Slough was flowing, and the water was uncharacteristically clean. Dozens of Meadowlarks were singing their alluring songs, and numerous hawks, the Red-shouldered, the Red-tails, and Harriers were patrolling, looking for ground squirrels emerging from their burrows.
|Tule Elk at San Luis. There were just two left in the 1880s|
On this small patch of valley floor, environmental managers of the Fish and Wildlife Service are trying to restore a bit of the valley to something that resembles the land the once provided food and shelter to millions upon millions of birds, mammals, reptiles, amphibians and many others. The Great Valley was once America's Serengeti Plains, one of the richest wildlife habitats on the planet.
I haven't said much about the criminal drama that unfolded last month at the Malheur National Wildlife Refuge. I was waiting for some kind of resolution. Four of the terrorists are still holding out at the refuge wondering where all their brave "patriot" friends are, so the situation remains unresolved. But sixteen of the gun-toting thugs are under indictment, and LaVoy Finicum lies dead in the ground, a self-appointed "suicide by cop". Some people are calling him a patriot and a martyr. I call him a common criminal who ran a roadblock and then tried to draw a gun on law enforcement officers.
|I believe it is a juvenile Red-tailed Hawk|
This isn't opinion, this point of view is a matter of law. People decided to take up arms against a duly elected representative government and tried to effect political change with guns. These were criminal acts that followed years of threats and intimidation. These people can try to pretend they were following some bizarre interpretation of the Constitution, but the Constitution makes clear that the powers of government do not lie in the hands of people with guns trying to steal public land for their own private use.
|Grasslands at San Luis. Brewers Blackbirds in the tree in the distance.|
I'm not sure these people even understand the principle of civil disobedience that brought about the Civil Rights Act and the Voting Rights Act. In that era people broke the law on purpose, but they expected to be arrested and were ready to be imprisoned to bring about legal changes in the country. They didn't carry heavy weaponry and threaten to kill public officials. They instead paid a heavy price themselves, even to the point of death in too many cases.
|A Loggerhead Shrike|
|Salt Slough, a tributary to the San Joaquin River|
Private landowners are often responsible and are responsive to efforts to preserve part of their holdings for wildlife. But they can't be expected to understand and act on the fact that their portion of the landscape is a small piece of a wildlife network with connections from the far northern Arctic to the tip of South America. Only the federal government can do this, and its role in wildlife management is both legal and supported by the vast majority of the citizens of our country. Only the federal government can provide protection for the breeding grounds of migratory geese and cranes in the far north and at the same time provide wintering grounds in California and other parts of the southwestern states. Only they can provide resting places for the birds at refuges between the two extremes of the migratory routes. And only the federal government can enter into diplomatic agreements to protect animals whose migratory pathways carry them over international borders.
|Great Blue Heron on Salt Slough|
Federal management of grazing lands has not been perfect, but there are many examples of cooperation between different stakeholders in the debate. The vast majority of ranchers are law-abiding citizens. But those who decide to take up arms against the government must be dealt with proportionately. Anyone who threatens the life of another, and acts on that threat needs to be in prison, and their weapons taken away. The moment these criminals brandished guns they lost their place at the table.
It was a beautiful day today at the San Luis National Wildlife Refuge. I could wander over the grasslands and imagine how this valley once was. So much has been lost, but much still remains, and it was both a privilege and a right to be there on this really early "spring" day. I salute those who work at these refuges and who are fighting to do the right thing, sometimes in the face of threats and intimidation. Thank you for the good work that you do.
|Beaver or Muskrat?|
The San Luis National Wildlife Refuge protects the floodplain of the San Joaquin River between Turlock and Los Banos in California's Great Valley. There is an excellent visitor center, and a number of available auto tours and hiking trails. For more information, check out their web page: http://www.fws.gov/refuge/san_luis/.