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.


Factors Determining Snowmelt in the Rocky Mountains

November 11, 2022

TomMC_EPOD.ColoradoRockiesSnowpack (004)

TomMC_EPOD.60.ColoradoRiverConditionsJuly2022 (003)

Photographer: Thomas McGuire

Summary Author: Thomas McGuire

Some 40 million people in the Southwestern United States depend, in a
large part, on the Colorado River for agricultural and municipal
water. About 90% of Colorado River water originates from melting
snowpacks in the Rocky Mountains, such as shown on the photo above at
Independence Pass, Colorado (taken in July 1977).

2021-2022 was a relatively decent year for snowfall in the Rockies, yet
both major reservoirs, Lake Powell and Lake Mead, are at
dangerous and historic low water levels. And they’re expected to
continue to go down in the coming year.

With warming of the climate in the Southwest, the tree line has
been creeping up mountain slopes. Trees lose water by transpiration
from leaves and needles. Snow surfaces lose water by the process known
as sublimation. Because trees absorb more sunlight than highly
reflective snow, an early snowmelt exposes the dark soil, which absorbs
more solar energy. Additionally, dust blown from the dry soil onto
the snow makes the snow surface darker, absorbing even more sunlight
and further contributing to earlier snowmelt -- see chart above. This
confluence of factors is a challenge for the inhabitants of the
Southwest. Fortunately, there are many alternatives allowing the
residents to adapt to the “new normal.”


Independence Pass, Colorado Coordinates: 39.1086, -106.5640


Related EPODs

Factors Determining Snowmelt in the Rocky Mountains Storm
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Preparing for Winter in Northern Illinois Archive - South
Atlantic Hurricane

Climatology Links

* Aerosols: Tiny Particles, Big Impact
* JetStream - An Online School for Weather
* Climate History
* National Centers for Environmental Information
* Global Climate Animations
* NOAA Climate Analysis Branch
* Vital Climate Graphics

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

https://epod.usra.edu

--- up 36 weeks, 5 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.


Arizona’s China Wall

October 12, 2022


TomMc_ChinaWall

Photographer: Thomas McGuire

Summary Author: Thomas McGuire

Shown above is China Wall, a rock formation in the Tonto National
Forest, north of Scottsdale, Arizona. It forms a broken vertical wall
nearly a mile long (1.6 km), and about 10 feet high (3 m) and 5 feet
wide (1.5 m), draped over the summit of Bronco Butte (satellite
photo below). It was so-named because of its resemblance to the ruins
of the Great Wall of China, which is about two to three times
larger.

China Wall is a sill intrusion of rhyolite, a relatively common
igneous rock. Rhyolite has a composition similar to granite, but
due to relatively rapid cooling, the crystals are much smaller than
granite. The China Wall magma was injected into meta-sedimentary
rocks that are nearly half as old as Earth itself. Although the layer
of rock is oriented vertically, it’s inferred that the sill was
injected horizontally and the whole regional package was rotated into
the vertical position by a billion years of plate tectonic forces.
With the sparse vegetation found in the U.S. Southwest, bedrock
exposures often reveal the orientation of the layers.

TomMc_ChinaWall.jpg2b


China Wall, Arizona Coordinates: 33.9008, -111.8810


Related EPODs

Arizona’s China Wall Fossil Lake’s Legacy at Wyoming’s Fossil
Butte Wagon Tracks from the Old West? First Light on the Circle
Cliffs Anticline Mudcracks: Now and Then Mantling on Utah’s
Hogback Ridge
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 32 weeks, 2 days, 20 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.


Joggins Fossil Cliffs

December 12, 2022

P9070408-Joggins Cliffs

Photographer: Rick Stankiewicz
Summary Author: Rick Stankiewicz

The seaside cliffs near Joggins, Nova Scotia are a mecca for anyone
interested in fossils and are well worth the drive off the beaten path
to this small community in western Cumberland County. The above photo
is a section of this incredible 9 mile (15 km) stretch of shoreline
along the Bay of Fundy.

Joggins is famous for its rich fossil record going back more than
310 million years to the Pennsylvanian “Coal Age” of the Late
Carboniferous Period. During this time Nova Scotia was covered by a
tropical rainforest to which the fossil record attests. As early as
1871, the fossils from Joggins were considered the finest in the world
from this Period. In 2008 the Joggins Fossil Cliffs were designated a
UNESCO Natural Heritage Site.

When I visited this site with my wife in 2016, I was captivated by the
content of the displays at the “ Joggins Fossil Centre”, which does
an admirable job of illustrating the geology and history of this unique
landscape and the fossil record it both preserves and exposes for
discovery. Though not legal to “collect” at this site, a guided tour
will show fossilized specimens that have literally fallen from the
cliff-face to the shoreline below. With the highest tides in the
world, nature is exposing the fossil record on a daily basis.

P9070407-Ripples

One interesting example I witnessed on my tour was a plate-sized
example of “ripples”, from an ancient waterbed that had been fossilized
and now lay on the shore near the base of the cliffs (above). Our guide
picked it up to explain its significance to our group. I personally
found segments of plant stems both on the shore, amongst the rubble and
embedded in the cliff-face (below). The specimen shown here is likely a
section of a tree sized relative ( Calamites) of today’s smaller,
reedy horsetail rushes. Photos taken on September 7, 2016.

P9070398-Plant Stem

Photo details: Olympus TG-860 camera; f/6; ISO 125; 1/500th second
exposure.

Fossil Cliffs, Nova Scotia, Canada Coordinates: 45.694515 -64.449432


Related EPODs

Joggins Fossil Cliffs Salt Pans of Torre Nubia Glacial
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Storm Mountain Beautiful Alpine Lakes in the Sierra Nevada Range
Quechee Gorge in East Central Vermont
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 41 weeks, 21 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (21:1/186)