|
Archean Greenstone Pillow Lava In Michigan USA 3
The Archean Eon ( , also spelled Archaean or Archæan) is the second of four geologic eons of Earth's history, representing the time from . The Archean was preceded by the Hadean Eon and followed by the Proterozoic. The Earth during the Archean was mostly a water world: there was continental crust, but much of it was under an ocean deeper than today's ocean. Except for some trace minerals, today's oldest continental crust dates back to the Archean. Much of the geological detail of the Archean has been destroyed by subsequent activity. The earliest known life started in the Archean. Life was simple throughout the Archean, mostly represented by shallow-water microbial mats called stromatolites, and the atmosphere lacked free oxygen. Etymology and changes in classification The word ''Archean'' comes from the Greek word (), meaning 'beginning, origin'. It was first used in 1872, when it meant 'of the earliest geological age'. Before the Hadean Eon was recognized, the Arc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John William Dawson
Sir John William Dawson (1820–1899) was a Canadian geologist and university administrator. Life and work John William Dawson was born on 13 October 1820 in Pictou, Nova Scotia, where he attended and graduated from Pictou Academy. Of Scottish descent, Dawson attended the University of Edinburgh to complete his education, and graduated in 1842, having gained a knowledge of geology and natural history from Robert Jameson. Dawson returned to Nova Scotia in 1842, accompanying Sir Charles Lyell on his first visit to that territory. Dawson was subsequently appointed as Nova Scotia's first superintendent of education. Holding the post from 1850 to 1853, he was an energetic reformer of school design, teacher education and curriculum. Influenced by the American educator Henry Barnard, Dawson published a pamphlet titled, "School Architecture; abridged from Barnard's School Architecture" in 1850. One of the many schools built to his design, the Mount Hanley Schoolhouse still survive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
