As noted earlier, I had the good fortune to spend last week in Yosemite National Park, celebrating the wedding of my friends Jason and Lindsay, and in general poking around in one of the coolest places around. Below, a summary of the three-day trip:

Friday:
Lily and I flew to Modesto, California, and rented a car. It took about two hours to drive up to Evergreen Lodge, where we checked in and then headed out for a short hike in the Hetch Hetchy area. Hetch Hetchy was dubbed "Yosemite's sister valley" by John Muir in an attempt to keep it from being dammed. But the city of San Francisco had been destroyed in 1906 by earthquake-induced fire, and the call for a reliable water source was an important force in overpowering Muir's conservationist ideals. Ken Burns apparently explores this saga, the first instance of "development vs. conservation," in the second episode of his new National Parks series. (I saw the first episode, but haven't caught up on the rest of it yet.) The valley was dammed in the 1920's, creating the Hetch Hetchy Reservoir:


Here's the O'Shaughnessy Dam, named after the chief engineer of the project:


I didn't find it as spectacular as Yosemite, but it was sure a pretty place. Walking along the north side of the reservoir, I reaquanited myself with some fine Sierran granites and granodiorites. Here's a sweet little xenolith (or maybe an MME; how can you tell an MME from a mafic xenolith?):

Back to the Evergreen for the rehearsal dinner (Oktoberfest theme!) and then bed.

Saturday:
Up early, got some coffee, drove an hour to reach the Yosemite Valley. I liked how quiet things were compared to the throbbing pulse of summer. This view of El Capitan, for instance, is typically mobbed with tourists. This day, we had it to ourselves for five minutes or so, then shared it with one other car:


Time to stretch the legs! We decided to hike up to Vernal Falls. On our way up, the base of the falls was still in shadow, with low-angle morning sunlight dramatically illuminating the upper reaches of the falls:


Looking back down the valley we had climbed up... I like the dark shadow of the cliff merging with the dark shadows of the trees below:


But if we set the camera's F-stop a bit differently, we can see what's going on in all that shadow. There's the trail we climbed up, with fellow hikers for scale:


Up top, photographing the waterfall:


On our way back down, with more of the falls illuminated as the sun rises in the sky:


Looking north across the valley from where we parked our car, marvelling at the huge exfoliation joints there: rounding these exposed plutons into granite 'domes.'


... or Half Domes, as the case may be:


A view from further out, again with Half Dome the most striking landform:


Then, we headed back to clean up before the wedding. Great ceremony, amazing meal. Drinks, dancing, rhubarb jam, bluegrass, reminiscing with old friends and new. Ahhh.

Sunday:
Breakfast and coffee with the wedding party, then off to check out some big trees. We drove to the Tuolumne Grove of giant sequoias. It started snowing on the way there, but we didn't let that deter us. On the hike down from the parking area (where, by the way, they had closed the Tioga Road), we found this nice example of spheroidal weathering in an outcrop of granite:


But the real attraction was the enormous sequoia trees. Here's one:


And a dead one, with a car-sized hole cut through it:


I found these trees very impressive: they were just stunning in their grandeur and immense age. Snow continued to fall as we left. We had to get going to make our flight home. Somewhere on the way down the mountain, Garry Hayes and his wife passed us going up the mountain. Ships passing in the night -- sorry I missed you, Garry! We made a couple of roadside outcrop stops, then got back to Modesto and traded in the car for an airplane. Our "redeye" route back to DC took us through San Francisco and Los Angeles, and I ran into Thomas Friedman in the airport. Got back to BWI at 6am, and headed off to work...

Labels: california, glacial landforms, national parks, plants, travel, tv, water resources, xenoliths

Working through my backlog of e-mails, I find that I have a few more Rockies course final projects to share with the world:

Laurie's website on Yellowstone geothermal features.

Jared explores Ringing Rocks.

Kevin suggests "more study is needed."

Ken discusses Grinnell Glacier:

Amanda reviews the Tetons:

Labels: glacial landforms, glaciation, montana, mountains, stromatolites, volcano, water resources, wyoming

Holy guacamole. A-ma-zing.

Labels: asia, satellite imagery, water resources

My student Joel recently went up to Clarion County, Pennsylvania, where he encountered this striking example of a stream contaminated with acid mine drainage (lifeless rust-filled stream at right) merging with an undegraded stream (at left). Wow:

Photograph by Joel Bosch.

Labels: environmental, minerals, mining, pennsylvania, water resources

There's a proposal to turn the Luck Stone diabase quarry south of Leesburg into a big reservoir for increasingly-populous Loudoun County, Virginia. It would then be followed by other tapped-out quarries in the area. Collectively storing 8 billion gallons, the reservoirs could serve the surrounding area for up to 120 days during a prolonged dry spell. The idea is to create the reservoirs by siphoning of about 40 million gallons a day from the Potomac River, starting in 2017.

These diabase intrusions are mafic igneous rocks that intruded into the crust during the opening of the Atlantic Ocean. As Pangea broke apart during the Triassic and Jurassic, a huge system of sags opened up in the crust. These low spots were the sites of (a) intense sedimentation, since water flows downhill, and (b) mafic igneous intrusions, since the thinned crust allowed decompression melting of the underlying mantle. (Partial melting of an ultramafic source usually yields a mafic distillate.)

The entire system of failed rift valleys extends along the same trend as the Appalachians, but further east, all the way up to the Bay of Fundy. Collectively, they are called the Newark Supergroup, after one of the larger rift basins in Newark, New Jersey. Dirty sandstones filling that basin were the source of all the 'brown stone' that made the brownstones of New York City. Locally, in our own Culpeper Basin, the main rock that is quarried is diabase, which has a coarser crystal size than basalt, but smaller crystals than a gabbro. It is distinguished by a lot of pyroxene.

Source for the reservoir proposal news: Today's Loudoun Extra, from the Washington Post

Labels: atlantic, culpeper basin, jurassic, minerals, mining, new jersey, new york, news, triassic, virginia, water resources

The International Year of Planet Earth may have declared a list of "the Earth's ten most spectacular places." At least that's what they're saying at the Discovery Channel's new Discovery Earth site, where they have a rundown of all ten (with photos). (No mention of it at the IYPE site, though: It may be that the Discovery Channel is just highlighting ten of the many, many U.N. World Heritage sites... their language is unclear as to who decided on these particular ten.)

Regardless, the photos will whet your appetite. With my visits in bold, they are:

• The Giant's Causeway, Northern Ireland (posts on NOVA Geoblog)
• Wadi Al-Hitan (Valley of the Whales), Egypt (Eric's been posting on this recently)
• Lake Baikal, Siberia (deep, big)
• Komodo National Park, Indonesia (big monitor lizards; my friend Kenny has been)
• Grand Canyon, Arizona, USA (posts on NOVA Geoblog)
• Ilulissat Icefjord, Denmark (glacial beauty)
• Wulingyuan, China (quartzite pillars and indigenous fauna)
• Surtsey, Iceland (46 years old this year)
• Central Amazon, Brazil
• Great Barrier Reef, Australia

Labels: antrim coast, asia, australia, china, fossils, giants causeway, glaciation, grand canyon, ice, reefs, south america, travel, water resources

Yesterday, I mentioned the results of the Virginia DGMR symposium's breakout session on Blue Ridge geology. Today, for completeness' sake, I'll also post the results of the other two breakout sessions (one on the Valley and Ridge province, and one on water issues):

Session 2: Unresolved Issues in Valley and Ridge Geology
In general, the consensus was that continued support for detailed geologic mapping is needed, which provides essential information for a number of major issues that need to be resolved. Major issues discussed during the Breakout Session generally fell into one or more (much overlap) of the following categories:

Geologic Framework:
Need to find better ways to communicate the value of geologic mapping (e.g. beyond the anticipated development along the I-81 Corridor).
Better communication between geologists working in the BR and VR regarding the timing and influence of major tectonic events; presently somewhat disconnected.
Evaluate the influence of basement normal faults.
Better understanding of the sequencing of thrust faults in the VR.
Better understanding of the transition between brittle and ductile fracturing in the VR.
Influence of the Rome Trough on VR structural framework.
Better understand the link between Allegheny Front and BR overthrust.
Better define stratigraphic units with economic and geohazard potential that are currently lumped (e.g. SDu, Ols, etc).
More focus on deep stratigraphy, where there is potential for deep saline aquifers that may provide geologic storage of CO2.

Geologic Hazards:
Identify, evaluate, and prioritize geologic hazards in VR.
Karst/sinkhole digital database; better understanding of the interplay between geologic controls and land use.
Large block slides, recognizing risk areas.
Better understand the nature of brittle on ductile fractures in context of subsidence risk along the western margin of the Blue Ridge
Quaternary history (e.g. evaluation of flood risks)

Economic:
Better understand the distribution of high-Ca limestones; not just limited to the middle-Ordovician units.
Stratigraphic relationships between Devonian shale units (e.g. Millboro, Marcellus)
Evaluate occurrences and distribution of non-polishing aggregate resources.
Evaluate occurrences and distribution of high purity silica (glass sands); (e.g. depositional character of the Oriskany).

Other:
Source and structural implications of Eocene-age igneous rocks (Highland Co) and alkaline dikes (Augusta Co).
Need for improved educational outreach.

Session 3: Integrating Geologic and Hydrologic studies - Benefits and Challenges
The group was divided into geologic information providers, hydrologic information providers, and hydrogeologic information users. The provider groups developed a list of the most important types of information they provide. The User group developed a list of the most important types of information they need. Based on the results of this exercise and the interest of the group, the remainder of the meeting focused on addressing gaps in available information for end users.

Geologic data providers provide:
Geologic formation information - descriptions, structure data, "cover" materials
Fracture/joint data and analysis
Detailed and regional maps
Ground truth on karst features

Hydrologic data providers provide:
Well data - location, yield, logs, geochemistry
Spring data - location, discharge, geochemistry, dye trace results
Water use information - ground water and surface water
Technical /Assistance
Hydrographs

Users of hydrogeologic information need:
Geologic maps at an appropriate scale.
Water well data - yield, depth to water table, etc.
Hydrographs

Users noted the following characteristics of information would be helpful:
Widely available and accessible information (Internet)
Standardized - uniformity of format and methodology (example pumping tests) on at least a statewide basis
Geologic descriptions and maps could include a characterization of saprolite.

Providers and users believed there was good agreement between the type of information that is being provided and that which is needed. The clear problem was recognized to be a lack of data in many places and the lack of easily accessible information (digital format, available on internet)
To address this problem, it was suggested the users of hydrogeologic information may be able to provide some assistance, such as:
Well data - construction characteristics, yield, drawdown, geochemistry over time
Soil data - maps, field notes
GIS Capabilities and data processing - especially county governments.

An identified issue:
Disconnect in some cases between geologists and soil scientists

Next Steps:
Water for America initiative may be an opportunity for geologic and hydrologic data providers to work together at the state level and provide hydrogeologic information to end users.

Based on USGS efforts in Northern Shenandoah Valley, integrated studies have both benefits and challenges. A future meeting to highlight these may be helpful to state level geologists and hydrologists.

Labels: caves, conferences, geology, valley and ridge, virginia, water resources

I saw David Byrne (formerly the frontman of the Talking Heads) perform last night in Baltimore. He did a great job, as he always does. (This was my fourth time seeing him in concert.)

One of the Talking Heads biggest hits (featured on NPR's list of the most influential songs of the previous century) was "Once in a Lifetime" (1984). Listening to him sing it again last night, I was struck by the geological undercurrents. I thought I would share a few of the topical lyrics that have a peripheral relevance to this blog:

On hydrology:

"Letting the days go by/let the water hold me down
Letting the days go by/water flowing underground
Into the blue again/in the silent water
Under the rocks and stones/there is water underground"

On oceanography:

"Water dissolving...and water removing
There is water at the bottom of the ocean
Carry the water at the bottom of the ocean
Remove the water at the bottom of the ocean!"

On the principle of uniformity ("uniformitarianism"):

"Same as it ever was, same as it ever was,
Same as it ever was, same as it ever was"

Also, from a different Talking Heads tune ("Life During Wartime"), Mr. Byrne offers us this epistle, clearly referring to the value of studying for open-book geology lab practicals:

"Burn all the notebooks
What good are notebooks?
They won't help me survive!"

Mr. Byrne may be coming to a concert hall near you. Check out his tour dates here. Listen to his new album for free online here. He also keeps a blog (which he calls a "journal," and it occasionally features geological musings, as in this example.)

Labels: geology, music, oceans, water resources

It started raining in DC on Sunday, and it basically hasn't quit since then. Rock Creek is running high and frothy, and the Potomac has about seven times as much water in it today as it did 36 hours ago. The USGS has only one gauging station on the Potomac in the Piedmont -- at Little Falls, approximately on the DC/Maryland border. Here's what that gage's data (available free online from the Survey) tells us (as of last evening) about the river's recent discharge trend:

Labels: dc, nova, piedmont, rivers, sediment, water resources

At the end of the northeastern GSA meeting yesterday, we loaded our NOVA crew up in the van and drove up to see Niagara Falls itslef. Here's the students (Laura, Victoria, Spencer, and Jason) at the American Falls. There were huge masses of ice built up down in the Gorge as the mist froze: quite a scene. The place was practically empty though -- very few visitors. Good to get up here and check it out. The flow you see here is 25% of the Niagara River's actual discharge. 75% gets diverted into electricity-generating projects on both the US and the Canadian sides of the river. (The buildings you see in the background are in Canada.)

We have another half-dozen talks to go to this morning, but then we hit the road back to NOVA. I just looked out the window -- and there's a couple inches of fresh snow on the ground!

Labels: falls, nova, water resources

A new paper in Water Resources Research suggests that Lake Mead, Nevada, may be dry by the year 2021. Authors Tim Barnett and David Pierce (both of Scripps) base this austere prediction on two things: (1) increasing projected rates of water use in the American southwest, as well as (2) climate change projections which suggest the region will receive less precipitation. They also posit a 50% chance that the lake level will drop too low to allow hydroelectric power generation by 2017. That's only 9 years from now!

It would seem that it's time for some conservation measures. When I lived out in California, I was struck by a major design flaw in the aqueducts which transport water from reservoirs in the Sierras and the Colorado River system to the centers of population: they're uncovered! These big long uncovered troughs full of water encourage the active evaporation of much of the liquid they carry. I'd imagine that just putting some tarps over the top of them would make a huge difference in conserving water that would otherwise be lost to the atmosphere. Maybe this has already happened: I left California in 1998, and I recall some post-September-11 (2001) talk about how the aqueducts were susceptible to being poisoned, so maybe they've already been covered up in the name of homeland security.

Check out the picture of the lake in October of last year (by Ken Dewey of the University of Nebraska). A glaring white "bathtub ring" shows how much the lake level has dropped due to the recent string of drought years the west has experienced. In early July, at the end of our Grand Canyon rafting trip, my Dad and brothers and I will float into the upper reaches of Lake Mead, and we'll likely see something like this in person. I'll be sure to post a blog reaction to that when I see it.

Reference:

Barnett, T. P., and D. W. Pierce (2008), "When Will Lake Mead go Dry?," Water Resour. Res., doi:10.1029/2007WR006704, in press.

For more details on the new study, see the press release on Eurekalert.

Labels: global warming, grand canyon, water resources