rocks
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Earth
Geologists rewrite textbooks with new insights from Grand Canyon’s Cambrian rocks
GSA Today’s cover features the Cambrian period of the Grand Canyon. Credit: GSA Since shortly after our planet formed, Earth’s 4.6 billion year history has been dominated by single-celled life. About 500 million years ago, a dramatic event called the Cambrian “explosion” occurred, during which an incredible diversity of life forms was left behind in the rock record. These fossils…
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Space & Cosmos
New research shows that most of the space rocks that hit Earth come from a single source
The sight of a fireball streaking across the sky brings wonder and excitement to children and adults alike. It reminds us that the Earth is part of a much larger and incredibly dynamic system. Each year, approximately 17,000 of these fireballs not only enter the Earth’s atmosphere, but also survive the perilous journey to the surface. This gives scientists a…
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Space & Cosmos
Fossils in rocks frozen in time hint at ancient climate on Mars
An ancient giant ripple imaged by the High Resolution Imaging Science Experiment on Terra Sirenum, Mars, has consistent wavefront wavelengths, numerous cracks and craters, and may be partially covered by ancient lava flows. Courtesy of NASA/JPL/University of Arizona. Long ago, wind and water currents shaped Mars’ soft sands and sediments into dunes, ripples, and other landform patterns called bedforms. Over…
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