Soil
Bedrock on Isle Royale is basalt or sandstone and conglomerates on the 1100 million year old Midcontinent Rift. Most of the island is covered with a thin layer of glacial material. A number of small native copper mines were active in the 1800s but mining was never really prosperous. Recent analyses by the USGS of both unmineralized basalt and copper-mineralized rock show that a small amount of naturally-occurring mercury is associated with mineralization.
Read more about this topic: Isle Royale National Park
Famous quotes containing the word soil:
“As I drew a still fresher soil about the rows with my hoe, I disturbed the ashes of unchronicled nations who in primeval years lived under these heavens, and their small implements of war and hunting were brought to the light of this modern day.”
—Henry David Thoreau (1817–1862)
“Let him
Who was love’s teacher teach you too love’s cure;
Let the same hand that wounded bring the balm.
Healing and poisonous herbs the same soil bears,
And rose and nettle oft grow side by side.”
—Ovid (Publius Ovidius Naso)
“But men labor under a mistake. The better part of the man is soon ploughed into the soil for compost. By a seeming fate, commonly called necessity, they are employed, as it says in an old book, laying up treasures which moth and rust will corrupt and thieves break through and steal. It is a fool’s life, as they will find when they get to the end of it, if not before.”
—Henry David Thoreau (1817–1862)