• ES Picture of the Day 12 2022

    From Black Panther@21:1/186 to All on Sat Nov 12 11:01:06 2022
    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


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    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

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  • From Black Panther@21:1/186 to All on Wed Oct 12 12:00:36 2022
    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


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    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
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  • From Black Panther@21:1/186 to All on Mon Dec 12 11:01:12 2022
    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


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    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

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