Less responsive

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Dolomite is less responsive to acid. With her sledgehammer, Anita took many pounds of roadcut, and not without effort. Again and again, she really had to slam the wall. Looking at the fresh surface of a piece she removed, she said she’d give odds it was dolomite. It was not responsive to acid. She scraped it with a knife and made powder. Acid on the powder foamed. “This dolomite is clean enough to produce beautiful white marble if it were heated up and recrystallized,” she said. “When it became involved in the mountain building, if it had got up to five hundred degrees it would have turned into marble, like the Dolomites, in Italy. There is not a lot of dolomite in the Dolomites. Most of the rock there is marble.” She pointed in the roadcut to the domal structures of algal stromatolites-fossil colonies of microorganisms that had lived in the Cambrian seas. “You know the water was shallow, because those things grew only near the light,” she said. “You can see there was no mud around. The rock flexplek huren utrecht is so clean. And you know the water was warm, because you do not get massive carbonate deposition in cold water. The colder the water, the more soluble carbonates are. So you look at this roadcut and you know you are looking into a clear, shallow, tropical sea.” With dry land adrift and the earth prone to rolling, that Cambrian sea and New Jersey below it would have been about 20 degrees from the equator-the present latitude of Yucatan, where snorkelers kick along in transparent waters looking through their masks at limestones to be. The Yucatan peninsula is almost all carbonate and grew in its own sea. As did Florida. Under the shallow waters of the Bahamas are wave-washed carbonate dunes, their latitude between 20 and 26 degrees. At the end of Cambrian time, the equator crossed what is now the North American continent in a direction that has become north-south. The flexplek huren rotterdam equator came in through the Big Bend country in Texas and ran up through the Oklahoma panhandle, Nebraska, and the Dakotas. If in late Cambrian time you had followed the present route of Interstate 80, you would have crossed the equator near Kearney, Nebraska. In New Jersey, you would have been in water scarcely above your hips, wading among algal mounds and grazing gastropods. You could have waded to the equator.

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