EPOD - a service of USRA

The Earth Science Picture of the Day (EPOD) highlights the diverse processes and phenomena which shape our planet and our lives. EPOD will collect and archive photos, imagery, graphics, and artwork with short explanatory
captions and links exemplifying features within the Earth system. The
community is invited to contribute digital imagery, short captions and
relevant links.


Volcanoes of the Northern Oregon Cascade Range

January 26, 2023

221216-14
PacNWtectonics

Photographer: Marli Miller
Summary Author: Marli Miller
The Cascade Volcanoes form a linear chain that runs north-south
from northern California to southern British Columbia. They form a line
because they’re fed by magma that originates by subduction of
the Juan de Fuca Plate beneath North America -- and the subduction
zone trends north-south (see schematic figures below).

This photo shows part of the volcanic chain, from South Sister
northward to Mts Jefferson and Hood; Mt. Adams in
Washington appears faintly on the horizon. Two rhyolitic lava
flows, erupted between 2000-2300 years ago, appear on the flanks of
South Sister. Notice also the many smaller peaks and cones. The Oregon
Cascades hosts more than a thousand volcanic vents that have erupted in
the last 2 million years. These vents are mostly basaltic in
composition but include andesitic and rhyolitic ones as well. Photo
taken on December 16, 2022.

Oregon’s Cascade Range Coordinates: ~44.000, -121.900


Related EPODs

Volcanoes of the Northern Oregon Cascade Range Mushroom Rock
State Park Subterranean Cathedral of Salt in Sicily Opalized
Fossil of a Cycad Cone Radial Stress Fracture Red Bar Natural
Bridge, Utah
More...

Geology Links

* Earthquakes
* Geologic Time
* Geomagnetism
* General Dictionary of Geology
* Mineral and Locality Database
* Mohs Scale of Mineral Hardness
* This Dynamic Earth
* USGS
* MyShake - University of California, Berkeley
* USGS Ask a Geologist
* USGS/NPS Geologic Glossary
* USGS Volcano Hazards Program

-
Earth Science Picture of the Day is a service of the Universities
Space Research Association.

https://epod.usra.edu

--- up 47 weeks, 3 days, 21 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (21:1/186)

EPOD - a service of USRA

The Earth Science Picture of the Day (EPOD) highlights the diverse processes and phenomena which shape our planet and our lives. EPOD will collect and archive photos, imagery, graphics, and artwork with short explanatory
captions and links exemplifying features within the Earth system. The
community is invited to contribute digital imagery, short captions and
relevant links.


Dance Hall Rock and Tafoni

February 24, 2023

TomMc_EPOD.DancehallRockTom (004)

TomMc_EPOD.TafoniWithinTafoniDanceHallRock2022 (003)

Photographer: Thomas McGuire

Summary Author: Thomas McGuire

In 1879 a group of 236 Mormons answered the call to trek 200 miles
(320 km) from their homes in southwestern Utah eastward across
partially explored high desert to populate the San Juan River
Valley. They had selected an unexplored “shortcut” to avoid an extra
hundred miles of travel.

This natural alcove (top photo), called Dance Hall Rock, provided a
place for the travelers to rest and to re-purpose themselves as scouts
looking for a way to access the Colorado River, more than 1,000
feet (305 m) down a sheer cliff. They found a cleft in the rock where
they had to chisel and dynamite an extremely steep and narrow ascent;
so steep that both wagons and horses had to be lowered separately on
ropes to the river below. After nearly a year of treacherous travel,
they arrived two persons stronger than they left with no fatalities and
two babies born along the journey.

The alcove probably resulted from a layer of resistant, Jurassic
aged Entrada sandstone, including many tafoni (bottom photo),
overlying less resistant sandstone layers that over time had been
hollowed out by wind and rain. Photos taken on May14, 2022


Dance Hall Rock, Utah Coordinates: 37.357151, -111.100474


Related EPODs

Dance Hall Rock and Tafoni La Scala dei Turchi Atacama
Lagoon and Sagittarius Arm of the Milky Way The Snake River’s
Formidable Hells Canyon Joggins Fossil Cliffs Salt Pans of
Torre Nubia
More...

Geography Links

* Atlapedia Online
* CountryReports
* GPS Visualizer
* Holt Rinehart Winston World Atlas
* Mapping Our World
* Perry-Castañeda Library Map Collection
* Types of Land
* World Mapper

-
Earth Science Picture of the Day is a service of the Universities
Space Research Association.

https://epod.usra.edu

--- up 51 weeks, 6 days, 21 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (21:1/186)