Carbon dating volcanic ash

Relatively cool conditions in the Arctic – see the blue tones in the global map at the top of this story — helped tamp down the global average in August.These conditions persisted into September, helping to limit the loss of sea ice in the high north.The production of marine sediment is more complex than it may seem.

It focuses on spectacular visuals related to the science of our planet, with an emphasis (although not an exclusive one) on the unfolding Anthropocene Epoch.Geological oceanographers have coined the terms "terrigenous" to describe those sediments derived from eroded material on land, "biogenic" for those derived from biological matter, "volcanogenic" for those that include significant amounts of ash, "hydrogenous" for those that precipitate directly from sea water, and "cosmogenic" for those that come from interstellar space.The seafloor, however, is not a random arrangement of these different sediment types.Oceanographers study sediment by taking long cylindrical cores, which individually can be as long as 18 to 30 meters (60 to 98 feet).Because the bottom of the ocean is extremely cold (only 1 to 3 degrees above freezing), the cores are stored in refrigerators onboard the research ship prior to being stored in large refrigerated repositories at shore-based laboratories.

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