September 5 (1976, 1985, 1986, 1987, 2002, 2014)
Green Valley Trail and Trash ~ Alta-Dutch Flat Geology

9/5/76    just before dawn, already the drone of insects, yellowjackets i guess, and the tooting of nuthatches. signature sounds for this time of year.

i moved my bed & stuff over on to the floor. such a beautiful floor, and the tongue-and-groove fits so tightly ~ i hope the boards don't shrink. All blind-nailed, except at the edges, where the walls will cover anyway. a strong floor, and with the 4 x 6 joists on 5-foot centers, a generous booming sound is generated when it is walked upon. i am well satisfied with the floor […]

yesterday there were some thunderstorms along the crest, and clouds outreaching from them extending a solid cover overhead, and only breaking up further to the west and downslope. the air was hazy and soft.

last night there was a lot of commotion over on the green valley trail, shouting back and forth and firing guns. i've got to get some signs posted. what a drag. and work on the cable entrance.

a red shafted flicker alights on the big leaning oak of arches, and squeals. […]

i would like to thin out the live oaks to the east, to better see the sunrise sky.”

[Russell Towle's journal]

“September 5, 1985

Yesterday my brother and I drove up to Grouse Ridge and parked. Then we set off cross-country for the Black Buttes. For me it was a wonderful and exhilarating hike; for Richard it became a bit of an ordeal, for he developed blisters and turned away from the summit when just a quarter-mile short. I continued on, and then descended a steep gully to join him at Glacier Lake, where we watched whirling water beetles and then picked up the trail for the 3 miles or so back to the car. Many small lakes and ponds, some dried up in the late summer season; bear footprints in soft mud and quartz outcrops.”

[Russell Towle's journal]

9/5/86 Friday morning. What can I say about this week? Well. Beginning on Monday, the day after Tinker's Knob; I lazed around home for most of the day, and then wandered into town, where I ran into Bill. Went to his place for a beer. Some friends of his from Squaw Valley were on their way over to talk about some proposed timber harvests and new ski lifts in the Shirley Canyon area, and Bill invited me to stay. It seems as though there are constant assaults upon the last remaining wild or semi-wild areas in this part of the Sierra. [...] Bill gave me a book on zoning law to read; in order for the Shirley Canyon project to go ahead, the land will have to be rezoned. Later Bill and I went to Dingus McGee's for dinner…”

[Russell Towle's journal]

9/5/87   Morning, about 4:30. Smoke shrouds the stars.

Afternoon; back in the cabin after a walk around the meadow and the Big Oak grove. An orange light filters through the smoky air above, and hints of nostalgic Fall gain sway. My own nostalgia is to recall the days, which seem so long past, when I scrambled the deer trails through the oak grove, and marveled at the andesite boulders, the constant creep of soil, crackling rain of acorns and sweet afternoon light. I was entranced then by Moody Ridge, and eager to observe fine details, and treasure up the nuances of such a lovely place. 12 years ago, my eyes were fresher. Longer than I have lived at any one other place.”

[Russell Towle's journal]

September 5, 2002
Geology of the Alta-Dutch Flat Area
by Russell Towle

The rocks of the Alta-Dutch Flat area in particular, and the Northern Sierra Nevada generally, can be divided into two broad groups: the younger "superjacent" (lying-on-top) formations, and the much older "subjacent" (lying-beneath) formations.

The older rocks are sometimes called the "bedrock," and are much more like real rocks. In the Alta area they include slates and metamorphosed sandstones, etc., of the Shoo Fly Complex (oldest rocks in the Sierra, 450 m.y.); serpentine of the Melones Fault Zone (an old and almost entirely inactive fault; about 200 m.y.), and metavolcanic rocks of the Calaveras Complex (greenstone, etc., about 200 m.y.). These old rocks are turned up on edge, in long bands running parallel to the Sierra crest. When you drive out Drum Powerhouse Road to the powerhouse you pass through all three, Calaveras Complex, Melones serpentine, and at the powerhouse, a little of the Shoo Fly Complex.

These old rocks were added to the west edge of North America about 150 m.y. ago by "continental accretion," a consequence of continental drift. The old rocks used to be ocean sediments (Shoo Fly Complex), basaltic ocean floor (Melones serpentine), and oceanic volcanic deposits (Calaveras Complex, eastern part). When North America was moving west, and the Pacific Ocean floor was moving east, these rocks were bulldozed right into North America and became part of the continent.

Sitting on top of these turned-up-on-edge old rocks of the subjacent series are the younger rocks of the superjacent series. The Eocene river gravels are the oldest. These can be seen in the red banks beside Highway 80 just west of the Dutch Flat exit. These gravels are from a large river which flowed over a floodplain of deep sediments. In this ancient, Eocene landscape, the Sierra were just low hills and ridges with sluggish rivers meandering through broad valleys. Then volcanic eruptions started to bury this landscape. First rhyolite ash almost filled many valleys in a long series of eruptions beginning about 30 m.y. ago. This is the Valley Springs Formation. The white rocks which are like sandstone, exposed near Lake Alta and in the railroad cuts just east of Alta itself, are this rhyolite ash.

After the Valley Springs Formation almost buried the old landscape, andesite mudflows from other volcanoes finished the job. They are called the Mehrten Formation. These mudflows completely filled the old valleys and made a large plateau over all this part of the Sierra. The flat-topped ridges all around near Alta are remnants of this plateau. The andesite mudflow is about 5 to 15 m.y. old.

Around five million years ago, the Sierra began to tilt up like a giant trap door. The uplift occurred along a series of faults along the east side of the Sierra which are all still quite active. In the Donner Pass area, east of Alta, there has been about 4000' of uplift. There has been much more in the Southern Sierra, maybe 10,000'. The uplift caused the Sierra to slope more steeply to the southwest.

As the Sierra grew higher, the Ice Ages began, and brand new canyons were formed. These canyons cut quickly through the young volcanics into the old bedrock. They kept on cutting farther and farther down into the bedrock. Even though our modern canyons, of the Bear River, and the North Fork American River, are around five million years old, geologists call them "young," because they are still getting deeper, and are very steep and deep, and are much younger than all the rocks around them.

The river "bars" made famous by the 49ers are deposits of glacial outwash sediments, from the last glaciation, which ended about 12,000 years ago. The glaciers came down the Bear River almost to Drum Powerhouse, and down the North Fork American to about Humbug Canyon. From the lower ends of these glaciers long trains of sediments ran down the canyons all the way to the Sacramento Valley. When the glaciers melted away and stopped adding all the sediments to the rivers, they were able to erode these sediments away. Only vestiges are left, which are the gravel bars of the 49ers. One of the best examples of these is Pickering Bar, below Gold Run on the North Fork of the American.

800# of Trash Removed from Green Valley

On Wednesday September 3, 2014 the efforts of many people culminated in a grand achievement. There is way less trash now, in Green Valley.

At cleanup events in years past, we carried out some of the worst of the gruk, but no way could get it all. We collected and bundled what we couldn't remove, above the high water line, and in an area open enough to accommodate a helicopter landing. Here's Gay, Walter and Caroline, drying out stuff before compiling it—this was a year or two ago on a cleanup hosted by NFARA (North Fork American River Alliance):

This summer, Eric Peach of PARC (Protect American River Canyons) got busy connecting people and agencies. Green Valley comprises a mix of land ownership—Tahoe National Forest, BLM, and private owners. Eric got support from Jeff Horn at BLM, and I don't know just who he connected with at TNF; but somehow he got a lead also to contact the CHP, and requested help lifting out the pile with their helicopter based in this area that is sometimes used for canyon rescues. They set up a date to do the liftout as a training session—September 3, 2014.

On Monday September 1—Labor Day in 2014—Ron, Cindy, Gay, Karen, Dale and Brian gathered to bundle...

and haul the most recent crop of garbage left by visitors, through the valley trails to the meadow gathering point. Some of the items included a broken-in-half kayak, old ripped and yucky sleeping bags, empty fuel cans, batteries, plastic of indeterminate history, real junk.

 The gathering point was in the meadow just east of the old hotel site and spring.

Will it all fit? Ron determines that we might be able to get it all in two net loads, but may need 3 nets.

Lift out day dawned gloriously bright, clear, sunny and blue, and a little bit cooler than Labor Day. Ron, Eric and Cindy hit the Green Valley Trail early to carry down the haul nets, bundle even more gruk, and prepare the loads for the lift.

Eric and Ron on the Green Valley Trail, carrying down the haul nets:

Green Valley, on the morning of the lift out:

One of the local residents:

The valley team loads all the trash into the two nets.

The helicopter arrives, right on time!

Cindy and Ron hook it up...

and get out of the way!

The first load leaves the valley!

And arrives over the drop zone, at Casa Loma. Jeff Horn, of the BLM is waiting at far right, where Eric's rig is parked, awaiting the loads.

Jeff signals to the pilot that the load is unhooked.

Between the loads, an oil train passes through (arrghh)... 

 The second load arrives:

Ohmigosh, there's a guy standing on the runner!

Load 2 comes down:

Once unhooked, the helicopter lands nearby. Jeff coils the cable and waits for the blades to stop rotating before delivering it to the copter crew.

The copter crew, on the ground: CHP officers Joe Hagerty and Matthew Calcutt.

Jeff Horn with the CHP copter crew, Giant Gap  in the background.

The valley crew made the long, grueling HOT middle-of-the-day hike out of the valley and came to Casa Loma to load Eric's trailer. Jeff had already taken out the first load at this point. Here are Eric Peach, Cindy Goldman, and Ron Gould, tired, but SO HAPPY!

It was a wonderful day in the Great Canyon, Russell!

(We miss you. We carry on.)

No comments:

Post a Comment