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Jurassic |
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Time: |
208 to 187
mya |
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Duration: |
21 million years |
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Early Jurassic (245 to 240 million years ago) coal beds have been
identified only in Central America. Middle and late Jurassic coal beds (187 to 144 million
years ago) are found in Montana; British Columbia, Alberta, and the Northwest Territories
of Canada; and numerous states in Mexico. Jurassic coals often occur in numerous layers,
have low sulfur, and medium to high ash content. Some coal beds have reached a maximum of
fifty feet though the average is closer to three to five feet thick. |
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