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Fire and Ice (Geology 7) field trip 2009; Yosemite and the Long Valley Caldera area

Preparing for the Fire and Ice, I mean, the Geology 7 field trip...

Slate Quarry at Aqua Fria Rd. Hwy 140 just east of Catheys Valley, Sierra foothills.

The Fricot Nugget

The Fricot Nugget, explained

Flourite; it'll be on the test...

Maybe a Shasta Blue...

Tili and Brianna

The view from Wawona Tunnel overlook

Bridalveil Fall

Bridalveil Fall, Yosemite Valley, with Half Dome in the background

Half Dome from Glacier Point parking lot

Liberty Cap and Nevada Fall

Tenaya Canyon from Glacier Point

Rebecca telling us what we're looking at...

Another view of Half Dome from Glacier Point

Overhanging Rock & Yosemite Falls

Landscape in Motion

Can't have enough pictures of Half Dome

Bridalveil Fall

Looking up from Yosemite Valley at Sentinel Rock

Mono Craters of which Panum Crater is a member

Crater Mountain, Mono-Inyo Craters

Oh! Ridge lookout on Garbage Pit Rd (romantic?) off of Hwy 158

June Lake from Oh! Ridge outlook; recessional moraines on Hwy 158

View from Lookout Mountain off of U.S. 395, between the towns of June Lake and Mammoth Lakes.

Mammath Mtn. from Lookout Mountain which is a rhyolite dome that began to form after the Long Valley Caldera eruption some 600k years ago.

One of the Inyo obsidian domes viewed from Lookout Mountain

Inyo National Forest
Hot Creek Geologic Site

Hot Creek flows through the Long Valley Caldera in a volcanically active region

Fishing is OK on Hot Creek but they fenced us out...

Slow-moving lava entered a
lake, where interaction with water altered
the rhyolite and formed this perlite

View near Mammoth Yosemite Airport US 395

Convict Lake, a tarn in a cirque. The ridge in the background is a lateral moraine deposited by a glacier during the Tahoe glaciation.

Mt. Morrison roof pendant

Meta-sedimentary roof pendant and Mt. Morrison Sandstone

The Big Pumice (Sherwin Summit) Roadcut: from the bottom, Sherwin Till (bolders far left above van roof), (disconformity between the Sherwin Till and the Bishop Tuff) air fall Bishop Tuff, ash flow pyroclastic tuff (nuée ardente) and three vertical Tahoe Gravel clastic dykes, then Tahoe Gravel at top.

After an over-land adventure, we find the road into the Owens River Gorge...

Radial or rosette joint sets in Upper Bishop tuff probably formed by fumarolic activity

Another radial jointing set

Looing down into the Owens River Gorge

Lower Bishop Tuff is more strongly-welded with flattened and elongated pumice fragments (left), Upper Bishop Tuff consists of pale pink, poorly welded pumice shards and phenocrysts (right)

Wandering back...

Upper Bishop Tuff

Owens River Gorge looking down stream

Lateral moraines eastern Sierra

Soda Springs Meadow

Devils Postpile National Monument

One hundred thousand years ago, a lava flow of very uniform material formed a lake up to 400 feet deep which slowly cooled. As it cooled, it contracted and cracked, forming hexagonal columns.

The Postpile's columns average 2 feet (0.61 m) in diameter, the largest being 3.5 feet (1.1 m)...

...and many are up to 60 feet (18 m) long.

Shaped by Fire and Ice

Eighty thousand years later, a glacier flowed through the valley, overriding the formation and eventually revealing the sides and tops of the columns. Glacial polish can be seen at the top of the formation.

On top of the Postpile

Glacial striations

I'm thinking, Penstemon fruticosus or P. rupicola but that's just a guess...

Trailhead to Rainbow Falls

The most comfortable place I sat on the entire trip, ah...

The Minarets are the remnants of a 100 million year old caldera, pre-Sierra Nevada orogeny and maybe part of a volcanic island arc. The jagged features are created by the rock-shattering effects of repeated freezing and thawing. These peaks were never overtaken by glaciers.

A peaking view of Mono Lake from Panum Crater

Obsidian dome (left) inside of pumice cone (foreground and right) Panum Crater

Eastern Sierra Nevada from Panum Crater

Obsidian de-vitrifiication

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