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Hands On Mineral Identification helps you to identify over 14,500 minerals! By M. Darby Dyar, Ph.D. See our DVD collection.


Geology means, literally, the study of the Earth. Explore this section to understand the structure of the Earth and its surface features, what causes earthquakes and tsunamis, and why volcanoes form and erupt. Learn about minerals, which form the building blocks of rocks, and how rocks are made and destroyed. Learn about Earth’s fascinating history, the variety of life forms which have roamed the surface over the millennia, and the dramatic changes that have happened over Earth’s long history.

You can get your own minerals and fossils, as well as the Fall 2010 issue of The Earth Scientist on Rocks and Minerals in our online store!

Although we humans have never experienced fast <a href="/earth/climate/climate.html">global
warming</a>, our
planet has. And our planet keeps records of what happened. The oldest
records that the
<a href="/earth/earth.html">Earth</a> keeps
are in its
<a href="/earth/geology/sed_intro.html">rocks</a>.
In this image, <a href="/headline_universe/olpa/methane_28may08.html">geologists Chris von der Borch and Dave
Mrofka</a> collect
sediment samples in South Australia. These rocks hold clues to help
explain why climate changed abruptly 635 million years ago.<p><small><em>                    Courtesy of Martin Kennedy, UCR</em></small></p>Gold or Fool’s Gold? There are two easy ways to tell Fool’s Gold, the
  from real gold. First, pyrite leaves a black streak on a white tile whereas
  gold leaves, well, a gold streak. Also, pyrite is much harder than gold.
  Pyrite is made up of the <a
  iron (Fe) and sulfur (S).  Both of these two elements are among the <a
  most abundant</a> in the <a
  crust</a>.<p><small><em> Courtesy of Corel</em></small></p>A <a href="">study</a> of over 40,000 written entries in Irish Annals and ice core measurements shows a strong correlation between <a href="">volcanic eruptions</a> and extreme cold weather in Ireland over a 1200 year period, from 431 to 1649.  During this time up to 48 volcanic eruptions were identified in Greenland ice core records through deposition of volcanic sulfate in annual layers of ice. Find out more about <a href="">volcanoes and climate</a>.<p><small><em>Image Courtesy of Marco Fulle</em></small></p>Sinkholes are <a href="/teacher_resources/main/frameworks/esl_bi8.html">natural hazards</a> in many places around the world. They are formed when water dissolves underlying <a href="/earth/Water/carbonates.html">limestone</a>, leading to collapse of the surface.  Hydrologic conditions such as a lack of rainfall, lowered water levels, or excessive rainfall can all contribute to sinkhole development. On 2/28/2013, a sinkhole suddenly developed under the house outside of Tampa, Florida, leading to the tragic death of its occupant, Jeff Bush.<p><small><em>Image courtesy of Southwest Florida Water Management District</em></small></p>An <a href="">8.6 magnitude earthquake</a> struck on 11 April 2012 off of Banda Aceh, Sumatra, Indonesia, followed by a strong aftershock.  Earthquake motion was primarily horizontal.  A tsunami warning was issued for the Indian Ocean, but was cancelled at 12:36 UTC.  A tsunami was observed at 1 meter or less. Find out more about <a href="/earth/geology/quake_1.html">earthquake</a> and <a href="/earth/tsunami1.html">tsunami</a> processes. Check out the resources <a href="/teacher_resources/2011_AGU-NESTA_GIFT_Workshop.html">here</a>.<p><small><em>NOAA</em></small></p>How did life evolve on <a href="/earth/earth.html">Earth</a> during the <a href="/earth/past/Archean.html">Archean</a>, when the <a href="/sun/sun.html">Sun</a> was about 25% weaker than today?  The Earth should have been <a href="/earth/polar/cryosphere_glacier1.html">glaciated</a>, if <a href="/earth/climate/earth_greenhouse.html">greenhouse</a> gas concentration was the same as today.  <a href="">Researchers</a> studying the <a href="/physical_science/physics/atom_particle/isotope.html">isotopic</a> signatures of Earth's early atmosphere in <a href="/earth/geology/rocks_intro.html">rocks</a> from Northern Australia have ruled out high levels of <a href="/physical_science/chemistry/nitrogen_molecular.html">nitrogen</a> as a possible way to increase warming from <a href="/earth/Atmosphere/overview.html">atmospheric</a> <a href="/physical_science/chemistry/carbon_dioxide.html">carbon dioxide</a>.<p><small><em>Image courtesy of Manchester University</em></small></p>

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Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part by the National Science Foundation and NASA, our Founding Partners (the American Geophysical Union and American Geosciences Institute) as well as through Institutional, Contributing, and Affiliate Partners, individual memberships and generous donors. Thank you for your support! NASA AGU AGI NSF