Sunday, November 17, 2013

Rocks on the move: Glacial Erratics, Ice-Rafted Erratics and Lahars

Miscellaneous collection of traveling rocks/boulders I've visited in recent weeks. "Glacial" erratics were moved within glaciers. "Ice-Rafted" erratics were carried by icebergs during the Ice Age Floods. Icebergs holding boulders often grounded along the margins of Ice Age flood channels.

Teresa checks out the BIG rock.
We finally found time to visit the Lake Stevens glacial erratic. This is the largest known erratic left by the Puget lobe of the Cordilleran Ice Sheet [34' tall, 78' long]. Geology blogger Dave Tucker has more details on the Lake Stevens Erratic.
Erratic warning sign.

Other side of BIG rock.
A big thumbs up to the surrounding homeowners!!! Nice little park on streetside of Lake Stevens erratic.
Yeager Rock
Example of a glacial erratic on the east side of the Cascades. No moss or ferns! This photo was taken a couple years ago on the Waterville Plateau. Yeager Rock and many other basalt boulders were carried south by the Okanogan lobe of the Cordilleran Ice Sheet.
Wedgewood Erratic
Teresa inspects the Wedgewood Erratic. According to Wedgewood Erratic Wikipedia page ... This Seattle erratic was an early practice climb location for Jim Whittaker, who became the first American to reach the top of Mount Everest.
"Fantastic Erratic"
A huge erratic south of Lake Sammamish. Too slow with camera ... almost had "Dog for scale" ... he jumped off as I approached.
Should be "Ferntastic". Hard to see the rock.

Teresa Foster enjoys fall hike.

Salmon in Issaquah Creek. Issaquah Salmon Festival.
Salmon working hard in Issaquah Creek.

Snoqualmie Falls.
Big flow at Snoqualmie Falls.

Snoqualmie boulders
More on this area in a future post. Great stuff near Twin Falls where ice flowed in from two directions [One from Canada the other from Snoqualmie Pass area].
Use Space Needle to mark maximum Ice Age Flood high water mark? Nope! Too short. Aircraft beacon on top of Space Needle tower is only 605 feet above ground. The Columbia river normal elevation at Vantage is around 570 feet. Largest Ice Age Floods to sweep through the area had a surface elevation greater than 1,263 feet [Ice-rafted erratics have been found at this elevation by State Park rangers].
Nick and I have met several times in recent weeks near Vantage, WA. We're trying to round up video and photos to build a show featuring geology along Interstate 90 between Seattle and Spokane. The drainage on the other side of the river (above) is Ryegrass Coulee. Several ice-rafted erratics sit in Ryegrass Coulee ... hard to find at 70 mph.
"An Iceberg Graveyard"
Nick at Ginkgo State Park visitor center - Vantage, WA. Interpretive panels describes ice-rafted erratics stranded high above the Columbia River.
Teresa and Pasco Basin erratics [ice-rafted] last weekend.

Short video describes Ice-Rafted Erratics

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Ice-rafted erratic in Ryegrass Coulee.

Back to "Glacial Erratics"
Here's Nick between Ellensburg and Cle Elum - Elk Heights I-90 exit in the distance. The boulder was carried to this location by a huge glacier that was fed by ice flowing from Snoqualmie Pass and the drainages that now hold Lake Kachess and Lake Cle Elum.
Glacial moraine near Thorp, WA
I-90 winds through massive moraine that marks maximum advance of glacier mentioned above. The glacier that left this moraine is from a much earlier time than the recent rounds of Lake Missoula flooding. The 40 mile-long Yakima Glacier existed more than 600,000 years ago.
Tabbert grounded by fog
Tom Tabbert flew over from Spokane to help us shoot video of I-90 cutting through the big moraine. Morning fog at the Ellensburg airport delayed Saturday filming.
TTABS got the footage ... after fog lifted.

Tabbert approaches lower moraine.

Niece Abby sits on Ice-Rafted Erratic in Yakima Valley.

Abby and I were on our way to visit Grandma (Mom) & Grandpa (Dad).
Erratic #1 on map below

Erratics along I-82 just north of Exit 44

Can you help?

These erratics are marked #2 on map below. Impressive boulders near Ice Age Floods margin in Yakima Valley. Erratics marked #1 and #2 were probably stranded by the same iceberg and moved to edge of Ag ground? Anyone know the story or name of orchard owner?

Interstate 82 - Exit 44.

Tom Tabbert and Nick Zentner
Killing time near Thorp lahar while waiting for fog to lift at Bowers Field.
Thorp lahar in distance [Red arrow at left end - white band].
Lahar: Mudflow or debris flow composed of a slurry of pyroclastic material, rocky debris, and water. The material flows down from a volcano, typically along a river valley.
Some amazing traveling rocks out here! The lahar near Thorp, WA is really cool. Material flowed to this location from a volcano that no longer exists near White Pass, WA. Obstacles like Manastash Ridge were not in place when the volcano erupted allowing flow from White Pass to Thorp area.

Rode in on the lahar from SW.

Same rock pictured in previous image [above Jeep].

Tabbert takes a look at lahar and Yakima River.

Geologists believe this pink mass of rock rafted in on the lahar.

Nick and Rick Spencer video featuring Thorp lahar.

Monday, May 27, 2013

What is Lava? - Pillow Lavas, Pillow Basalt and Palagonite

Honoli'i Beach north of Hilo Hawaii surfing
Earlier this month, Nick Zentner and I spent a few days in Hawaii filming 2 Minute Geology episodes on Hotspots, Volcano Types and Lava. We also shot "comparison" footage to include in several of our shows related to the  Columbia River Basalts. University of Hawaii at Hilo geologist Steve Lundblad was our host and guide. I sure enjoyed meeting members of Hilo's geology department (students and faculty) when Nick gave a talk to that group.
Sunrise over Hilo Bay on the Big Island of Hawaii
Sunrise iPhone view of Pacific Ocean - Lundblad home. Thanks for everything Steve & Nancy!!!

Steve Lundblad geology Hawaii Hilo
Nick and Steve filming 2 Minute Geology episode near Saddle Road summit.

Big Island of Hawaii
 Flew from Seattle to Kona. Stayed in Hilo.
Hawaiian Sea Turtle
Sea Turtle enjoys Hilo Bay
Hilo Hawaii attraction - Rainbow Falls
Rainbow Falls in Hilo is beautiful. A tropical rain-forest climate [with annual rainfall totals in excess of 10 feet] ... allows "houseplants" to grow wild.

 What is Lava?

Click above to view flowing lava and watch Nick sample molten lava.

Big Island of Hawaii - Lava plain
Road over the rock

Darcy Bevens leads hikers
Steve and Nick following University of Hawaii Hilo's volcano field expert Darcy Bevens. Thanks for the great hike Darcy!!!
Geologist on the Big Island of Hawaii - Steam from lava ocean entry
Steam from lava entering ocean in the distance.
Pacific Ocean lava entry
Pacific Ocean lava entry
Geologist Nick Zentner explains creation of pillow lavas and palagonite when lava flows into water.

Black sand beach
Black sand beach
Molten lava flow Hawaii
Hot flows are silver in the sun
Twin Pits lava volcanoes Hawaii
This feature was really cool!!! My photos don't capture the scene very well. Huge pothole-like holes called "Twin Pits". You can see where the 1974 lava flow spilled into pit on the right.
Hawaiian Volcanoes Twin Pits
Sorry Ice Age Floods friends! ... These pits are more impressive than any flood-carved pothole I've seen. It hurts me to say that! Nick for scale at top left.
Pele's Hair volcanic glass
Volcanic glass threads from erupting volcanos that looks like blonde hair. You can see it in photo above that shows Steve and Nick following Darcy. Pele is the Hawaiian goddess of volcanoes.

Vog in Hawaii
The wind helped us out and we only had to wear respirators a short time. Sulfur dioxide released by the erupting volcano is known as vog  (slang ... for volcanic fog or smog). 

Tsunami tree Hilo bay 1946 tsunami
Yikes!!! Hilo's recent tsunami history recorded on this tree. With several bands marking events [date and depth]. The top tag is at 26 ft.
Hilo tsunami
The highest tag marks 26 ft surge in 1946.
The tsunami is believed to have been generated during a magnitude 7.4 earthquake, when a large section of seafloor uplifted in the Aleutian Island chain (scientists are still trying to verify exact location). 

Hilo, HI tsunami 1946
USGS photo shows residents running from 1946 tsunami (wave visible in palm trees) that killed 159 people in Hilo.

Mauna Loa volcano Hawaii
 Mauna Loa
The long gentle slopes of Hawaiian shield volcanoes are deceiving. Hard to believe the summit in the distance is 13,679 feet!
Mount Rainier
I like this one better!!!
Mount Rainier view from plane on the trip home.