Recent Examples of tephra from the Web
Some 630,000 years ago, the supervolcano beneath Yellowstone National Park in Wyoming recorded its last catastrophic eruption, forming a caldera that nearly spans the park’s width and belching a thick layer of ash, or tephra, across North America.
The cores, presented here today at the annual meeting of the Geological Society of America, were captured at the farthest extent of the ash’s reach, recorded as wisps of tephra in finely sedimented, ancient mud uplifted near the ocean floor.
Both tephra layers also coincide with a stark temperature decline of 3°C, according to the core’s records of oxygen isotopes and fossilized plankton, with each episode lasting 100 years or more.
Understanding tephra is usually harder than finding it.
That volcano last erupted in 1985 producing lava flows with minor tephra.
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Britannica.com: Encyclopedia article about tephra
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