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    A study of over 40,000 written entries in Irish Annals and ice core measurements shows a strong correlation between the occurrence of volcanic eruptions and extreme cold weather in Ireland over a 1200 year period. Data analyzed in this study cover the period from 431 to 1649, during which time up to 48 volcanic eruptions are identified in Greenland ice core records through deposition of volcanic sulfate in annual layers of ice. You can find the study (open access), published on 6 June 2013 in IOP Publishing's journal Environmental Research Letters, at http://iopscience.iop.org/1748-9326/8/2/024035/article. Find out more about how volcanoes can influence climate.
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This diagram of Bowen's Reaction Series shows how the common silicate minerals crystalize at different temperatures.
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Bowen's Reaction Series

As magma cools slowly, elements within it become chemically bonded forming crystals of minerals. However, not all minerals form at the same time during the cooling process. Some minerals crystallize when magma is at a higher temperature, while others only crystallize when magma is at a lower temperature. Bowen's Reaction Series describes when the eight most common silicate minerals form during the cooling process.

In the Bowen's Reaction Series diagram to the left, minerals that form at high temperatures are listed at the top and minerals that form at lower temperatures are listed at the bottom.

Rocks that form from magma or lava cooled from high temperatures tend to contain a lot of iron and magnesium but little silica. These rocks are called mafic and tend to be dominated by dark colored minerals such as amphibole and pyroxene.

When magma cools slowly, minerals that form at cooler temperatures dominate the resulting rock. These rocks are called felsic and tend to be light colored with minerals such as feldspar and quartz.


Last modified June 17, 2003 by Lisa Gardiner.

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TES XXVI, 3 fall 2010 The Fall 2010 issue of The Earth Scientist, focuses on rocks and minerals, including articles on minerals and mining, the use of minerals in society, and rare earth minerals, and includes 3 posters!

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