Cape Breton's Magazine

> Issue 62 > Page 28 - C.B.'s Geology: A Talk on the Rocks!

Page 28 - C.B.'s Geology: A Talk on the Rocks!

Published by Ronald Caplan on 1993/1/1 (268 reads)

R' coal-bearing strata, sandstone *-'l gypsum, limestone f'yi' sandstone, conglomerate A Aspy terran'e B Bras d'Or terrene M MIra terrane P Precambrian Shield rocks A simple map of Cape Breton showing the four zones (Canadian Shield, Aspy terrane, Bras d'Or terrane, and MIra terrane) and the overlying sedimentary rocks (gypsum and limestone, sandstone, and coal-bearing units). Compare with the map on page 30. xzmented from the deposits in some of the lakes • 'the Bras d'Or Lake in particular, which is very deep and has got deep mud deposits in it. So that's a different part of the history, and that might be a different story. In a nutshell, that's what's happened to Cape Breton to make it the way it is. It's part of a much larger mountain chain that stretches from Alabama right up through Nova Scotia into Newfoundland. And then across the Atlantic through France and Britain into Norway. And even further north along the east coast of Greenland. The Atlantic Ocean is a young thing which opened up • split the giant continent apart, and left Nova Scotia on the west side and took Britain over to the east side. But geo? logically, they're very similar to each other. They're part and parcel of the same moun? tain belt. The red sandstones that you see here in Nova Scotia are the same red sandstones that were called the "Old Red Sandstones" by the first geologists 200 years ago in Britain. They are the same age, with the same fossils. And in some cases almost the same sequence of rocks: sandstone, covered by limestone, covered by gypsum. And we see that over in Britain as well. I don't know how much more I can say without going into details! I can tell you what the framework, the ba? sic skeleton of Cape Breton Island is made up from. We have surveyed all the High? lands. We haven't actually worked on many of the Lowlands. But the Highlands are the things that tell the old story. The Lowlands tell a more recent story, and then the Ice Age, the most recent story of all. River and such like. And left the Highlands available for us to see. And included with that, there's a really interesting climatic history. Because, it got cold, but then it got warmer than it is now. The climate has fluctuated between something which is more akin to Greenland and something which is more akin to Georgia • oh, 4 or 5 times over the last milHon years. And we're somewhere in between at the moment, in the climate that we have today. That climate history is doc- HORYUS Suf trior Sausage Co. Jltd. 21 Union Hwy. • NEW WATERFORD • B1H 4K4 Phone 862-7177 or 862-7178 Our fine products include: * Polish Sausage fe"''' -' * Salami * Kolbassa * Garlic Bologna ''''''' * Hot Pepperoni * White Pudding ''''' * Medium Hot Pepperoni * Black Pudding ''''lir * Sliced Pizza Pepperoni We take pride in using only the finest government inspected meats, and the care it takes to make our sausages. When you ask for HoryVs, you get the best ' SPECIALIZING IN QUALITY DELI MEATS FOR OVER 60 YEARS • The Highland areas have got the most complex and the longest geological history. We have to go back about 14 hundred million years or so, to get the very beginning of it. And that's right up in northern? most Cape Breton Island. Bordered by PoUet's Cove on the west, and a rather difficult-to-find line which runs from Cape North right down along the North Mountain. Not the Aspy Fault itself, but another fault which is a little bit in? land. Five kilometers inland from the Aspy Fault there's an? other line which marks these very old rocks. These rocks had been known about for many, many years, and no one really knew what they were. One of the main rock types that's in there is called anorthosite. Anorthosite is a rock that formed in the earth about 1500 to 1100 mil? lion years ago. It's a magmatic rock • that is, it was a rock which formed by melting deep down in the crust of the earth, and ponding as great reservoirs of magma, and grad- onricnSo Jonsered YOUNG'S POWER EQUIPMENT LTD. Millville * Boularderie * Phone 674-2008
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