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Explore the world with
images, information, and guides galore.
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of places.
What's
New?
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Chaco
Canyon: updated photos and recent
research
Moloka`i
Ctenophora:
recent research
Halema`uma`u
caldera: additional photos and map, Hawai`i
Volcanoes National Park
Moonrise
over sandstone pipe and Jurassic Entrada
Sandstone, Kodachrome State Park, Utah
School of spottail
grunt, Isla Espiritu Santo, Gulf of California
Aquatic
plants, Isla San Pedro Martir,
Gulf of California
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| Recent
Research |
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Tree rings are useful
for more than dating.
They can also help identify timber source areas, a
method called tree-ring sourcing. Recent work
indicates that most wood came from the Zuni
Mountains before 1020 CE
and the Chuska Mountains afterwards. So how did
Chaco builders drag 5-m beams 75 km without pack
animals and hardly scratch the wood? And once there,
how did they lift the heavy beams up to a six-story
height?
Diamond,
Jared (2016), Archaeology:
Sources of Chaco wood. Nature 529,
31-33. http://dx.doi.org/10.1038/nature16864
The
ancestral Pueblo peoples of the US Southwest
left established power centers (like Chaco Canyon, NM)
and moved north to the Mesa Verde region in the early
1200s. Within 100 years Mesa Verde was
deserted. Many hypothesis have been offered over
the years, but a growing body of work suggests a
combination of political disruption, cultural
conflict, resource shortage, violence, and
drought. These are forces very much at work in
today's Middle East and Africa, with a similar effect.
- Monastersky, R.
(2015), The
greatest vanishing act in prehistoric America.
Nature 527,
26–29. doi:10.1038/527026a
Archaeologists
are probing the ocean bottom along the
west coast of North America. This was dry
coastline 13,000 years ago when the last glacial
maximum was waning and sea level was about 100
meters lower than it is today. The first
Americans were moving in from Asia and
scientists hope to find evidence of a coastal
route.
- Marris,
E. (2015), Fishing
for the first Americans. Nature
525,
176–178. doi:10.1038/525176a
Genetic
studies have indicated a common origin of
Native American groups from Central and South
America. Some morphological studies have
suggested a more complex history. Here,
genome-wide data suggest a more diverse founding
population.
-
Skoglund, P., et
al (2015), Genetic
evidence for two founding populations of the
Americas.
Nature 525,
104–108. doi:10.1038/nature14895
- Favorable
geology and good management helped Rome
rise to become the capitol of an empire. Rapid
and excessive growth
(urban, population, and
resource) made the city
vulnerable
to natural disaster.
- de
Rita, D.,
Häuber, C.
(2014), The
smart city develops on geology: Comparing
Rome and Naples. GSA
Today 25,
4-9.
doi:10.1130/GSATG222A.1
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