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)
“Our own country furnishes antiquities as ancient and durable, and as useful, as any; rocks at least as well covered with lichens, and a soil which, if it is virgin, is but virgin mould, the very dust of nature. What if we cannot read Rome or Greece, Etruria or Carthage, or Egypt or Babylon, on these; are our cliffs bare?”
—Henry David Thoreau (1817–1862)
“Let none admire
That riches grow in hell; that soil may best
Deserve the precious bane.”
—John Milton (1608–1674)