Posted by: Rob Viens | May 28, 2012

Sugarloafing Around

Darwin was out collecting again today (May 28th)  – this time out near Sugarloaf Mountain. He writes:

“Visited the shore behind the Sugar Loaf & again obtained vast numbers of insects. — The situation being much the same as that of Barmouth many of the insects were closely allied; as I watched the elegant Cicindelæ running on this sand, Barmouth with all its charms rose vividly before my mind.” (May 28)

Since I recently wrote a lot about insects (particularly beetles, which Darwin was probably looking for today), I thought I’d say a few things about Sugarloaf Mountain itself.  Cicindelinae are tiger beetles, by the way (see Beetle Mania!), and Barmouth is a site in North Wales where Darwin liked to collect beetles.

Sugarloaf Mountain from the Atlantic Ocean (from Wikipedia Commons):

Sugarloaf Mountain from the Atlantic Ocean

Sugarloaf Mountain (Pão de Açúcar – “Loaf of Sugar” in Portuguese) is probably one of the most iconic features of Rio (especially to a geologist like myself who has never had the pleasure of visiting the city). The mountain draws its name from its shape.  In the 16th and 17th centuries Brazil was exporting significant amounts of sugar cane to Europe. The sugar would be placed in cone-shaped clay molds to form “loaves” of sugar for transport.  Reportedly they looked very much like the shape of the mountain – hence the name.

Sugarloaf from Iran (from Wikipedia Commons):


Sugarloaf Mountain plays a role in the earliest history of Rio, too.  Guanabara Bay (which the mountain marks the entrance to) was “discovered” by the Portuguese on January 1, 1502 and given the name Rio de Janeiro – the River of January. On March 1, 1565 the city of Rio was established as São Sebastião do Rio de Janeiro at the foot of Sugarloaf Mountain.  The site proved to be (1) defensible, (2) a gateway to the bay and (3) a good lookout point (because of the mountains). These factors proved to be important in the coming years as Rio was often the target of pirates and other countries looking to take the colony away from Portugal.  The city grew and in 1763 the Portuguese moved the “seat of colonial government” to Rio, and it remained the capital after Brazil gained its independence in 1822.

In 1912, a cable car was built to take tourists to the top of the mountain –  just under 400 meters above sea level (about 1300 feet). It was one of the first aerial tramways in the world used to carry people (the method had been used in mining for several centuries).

Cable car to the top of the mountain in the 1940’s (from Wikipedia Commons):

Sugarloaf tram in the 40's

Sugarloaf Mountain and nearly Corcovado Mountain are both made of very old granitic rocks of the South American Craton, that have been left standing after all of the “softer” rock has eroded away. These “mounds” seem to be common throughout the city of Rio – you can see several of them in the cityscape below.

Note Sugarloaf Mountain, Botafogo Bay and the entrance to Guanabara Bay in the upper left side of the photo (taken from Corcovado Mountain, from Wikipedia Commons):

Sugarloaf Mountain from the Atlantic Ocean

I really have to get myself to Brazil someday! (RJV)


  1. Makes me wonder if there is “sugar cube” basalt anywhere in the world. Or corn syrup lava flow?

  2. ha! this makes me want to take a hike and go “collecting” at Sugar Loaf as well! xx

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