Liberal Arts Blog — Geology: Why Is Rio So Beautiful? What Is Sugarloaf, Anyway? Is It a Karst Formation?

The iconic image of Rio De Janeiro, Brazil includes highly photogenic Sugarloaf mountain which always made me think of Guilin in China. I assumed that the formations were geologically the same. Apparently not. Sugarloaf is made of granite. The Giulin peaks are made of limestone and dolomite. The latter are karst formations. The former are not. So how is Sugarloaf classified geologically? It is called an “inselberg” or a “bornhardt.” An “inselberg” is “an isolated hill or mountain rising from a plain.” The inselberg “results when a body of rock resistant to erosion, such as granite, occurring within a body of softer rocks, is exposed by differential erosion and lowering of the surrounding landscape. Examples in the US include “Devil’s Tower” in Wyoming and “Stone Mountain” in Georgia. In Australia “Uluru” (made of sandstone) is by far the most famous. A “bornhardt” is domed hill or mountain regardless of isolation. A nickname for a bornhardt is “sugarloaf. <a href="https://john-muresianu.medium.com/liberal-arts-blog-geology-why-is-rio-so-beautiful-6686fa669453">Read More</a>