Black Mountain EarthCache
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Black Mountain is located 25 km south of Cooktown in Queensland. A roadside viewing area off the Mulligan Highway gives an excellent lookout to Black Mountain and interesting information about the mountain and general area.
Approaching Black Mountain from either Cape Tribulation or Cooktown it appears at first that the mountainside has recently been subject to bushfire. As you get closer to the mountain it becomes apparent that the black colouration comes from the vast tumbles of black rocks that make up the sides of the feature.
Black Mountain is a boulder jumbled mountain. Many millions of years ago, a mass of molten rock slowly solidified deep below the earth’s surface, forming a body of hard granite rock. An unusual jointing pattern occurred in the granite, which led to comprehensive fracturing of the rocky mass. Over time the top of the fractured granite was gradually exposed as softer land masses were eroded away.
Water permeated the network of fractures, extending through the solid granite rock, and chemical reactions reduced some of the harder minerals to soft clay. These clays were easily eroded, leaving behind the solid rock between the fractures which formed isolated rectangular blocks. The edges were progressively weathered until the blocks became rounded and irregular. The solid core of the mountain now lies beneath a spectacular layer of huge jumbled boulders, giving the appearance of a huge man-made pile of boulders tipped there by an endless fleet of monster trucks.
This is the traditional land of the Kuku Yalanji, who know this land as the Place of the Spear.
To log this cache please email us with the following:
1. How many years ago did the mountain first form?
2. What is the actual colour of the granite and what turns it black?
3. Attach a photo of yourself or something at the site, to your log.
I hope you enjoy your visit to this very interesting location.
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