Saturday, August 1, 2015

Sony Diaries #840: The Guelph Quarry, a short lesson in Geology, and how our existence on earth is but a a blink in eternity

the abandoned quarry  on the lands of the Old Reformatory in Guelph, mined by prisoners starting in 1820. The height of this exposed face is at least 200 ft high. the arrow points to a fossil (with water bottle for scale).
a marine fossil embedded in shale or sandstone.
The above fossil is an example of a marine specimen fossilized in stone created in an ancient tropical sea. Southern Ontario used to be close to the equator, and was covered by a warm tropical sea. Over the hundreds of millions of years, sediment was deposited on the sea floor, trapping and burying fossils such as this one.
The Silurian Guelph formation outcropping in the quarry face is primarily well-bedded dolostone containing many fossils including tabulate corrals, brachiopods, crinoids, and large cephalopods on the quarry floor. This rock is part of the Silurian reef barrier. ("Geology and Land Use Between Guelph and Hamilton: a Self-guided Tour", by W. Cheworth, P. Martini, et al. Revised Feb 1997).
The Silurian Period occurred from 443-416 million years ago, the third period in the Paleozoic Era. During this time, continental land masses were low and sea levels were rising. Most of western North America (e.g., Alberta's Tar Sands) and large parts of eastern North America were covered by a shallow sea. This meant rich shallow sea ecosystems with new ecological niches, extensive reef building,  and the first signs of life beginning to colonize the new estuary, fresh water, and terrestrial ecosystems. The latter part of theSsilurian Period saw the evolution of sea animals into land creatures.
Earth is said to be 4,500,000,000 years old. Early primates showed up 60,000,000 years ago, the great apes showed up (Family Hominidae) 20,000,000 years ago, human predecessors showed up 2,500,000 years ago, and anatomically modern humans came into existence 250,000 years ago.
AND, just 215 years ago, the Industrial Revolution in the early 1800's started changing the climate so that in another 200 years, this planet may be unlivable!!

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