The Sleeping Giant EarthCache
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The Sleeping Giant is a geologic formation on Sibley Peninsula which resembles a giant lying on its back. This cache can be viewed from the Terry Fox Scenic Lookout which is just east of Thunder Bay, Ontario.
Geology
Sleeping Giant Provincial Park lies within the Canadian Shield, in a vast area of ancient rock of Precambrian origin. The Shield forms the foundation of the North American continent and consists of some of the oldest rock on earth.
The Keweenawan diabase intrusive sills dominate the landscape in this area. Diabase, a very dark, basic, igneous rock was intruded as magma parallel to the bedding planes of the Sibley sediments. Differential erosion (the diabase is more resistant to erosion than the sediments) has resulted in tabular or sheet-like forms (sills) that cap the softer sediments and now stand out as isolated flat-topped mesas or southward-dipping cuestas. Mesas are formed by weathering and erosion. Variations in the ability of different types of rock to resist weathering and erosion cause the weaker types of rocks to be eroded away, leaving the more resistant types of rocks topographically higher relative to their surroundings. This process is called differential erosion. The most resistant rock types include sandstone, conglomerate, quartzite, chert, limestone, lava flows and sills. Lava flows and sills, in particular, are very resistant to weathering and erosion, and often form the flat top, or caprock, of a mesa. The less resistant rock layers are mainly made up of shale, a softer rock that weathers and erodes more easily.
The differences in strength of various rock layers are what give mesas their distinctive shape. Less resistant rocks are eroded away on the surface into valleys, where they collect water drainage from the surrounding area, while the more resistant layers are left standing out. A large area of very resistant rock, such as a sill may shield the layers below it from erosion while the softer rock surrounding it is eroded into valleys, thus forming a caprock. A cuesta is a ridge formed by gently tilted sedimentary rock strata in a homoclinal structure. Cuestas have a steep slope, where the rock layers are exposed on their edges, called an escarpment or, if more steep, a cliff. Usually an erosion-resistant rock layer also has a more gentle slope on the other side of the ridge called a 'dip slope'.
Erosional processes (e.g., freeze thaw) work on the zones of weakness (i.e., the columnar jointing) which results in the vertical cliffs (escarpments) that characterize the mesas and cuestas. The eroded materials collect as up to house-sized colluvial talus at the base of the cliffs. The most southerly area of the Sibley Peninsula, known as Thunder Cape, is overlain by flat diabase sills. The distinguishing feature of the diabase sills are the prominent vertical cracks or joints that present a distinct columnar structure along the cliff faces. Subsequent erosional processes, such as freeze and thaw activity produced the vertical cliff faces that characterize these mesa/cuesta landforms. From time to time these columns break away and fall to the base of the cliff where extensive talus slopes have developed. In the park, one billion years of erosion after the intrusion of the sills has resulted in the formation of five flat-topped mesas, sedimentary rock capped with erosion resistant diabase, that, when viewed from across the waters of Thunder Bay, resemble the profile of a recumbent human form. This characteristic landform feature is associated with the legend of Nanna Bijou and is known as the “Sleeping Giant”.
An Ojibwa Legend
A great tribe of Ojibwas lived outside Thunder Bay on Isle Royale. Because of loyalty to their gods and their industrious and peaceful mode of living, Nanna Bijou, the spirit of the Deep Sea Water, decided to reward the tribe.
The Great Spirit told the chief about the tunnel that led to the center of a rich silver mine. He warned that if the Ojibwa tribe were ever to tell the White Man of this mine he, Nanna Bijou, would be turned to stone. The Ojibwas soon became famous for their beautiful silver ornaments. The Sioux warriors, upon seeing the silver on their wounded enemies, strove to wrest the secret from the Ojibwas.
Torture and death failed to make the gallant Ojibwa tribesmen divulge their secret. Sioux chieftains summoned their most cunning scout and ordered him to enter the Ojibwa camp disguised as one of them. The scout soon learned the whereabouts of the mine.
One night he made his way to it and took several large pieces of the precious metal. During his return to the Sioux camp the scout stopped at a White Trader's post for food. There, without furs to trade, he used a piece of the stolen silver. Two White Men, intent upon finding the source of the silver, filled the scout with firewater and persuaded him to lead them to the mine. Just as they were in sight of "Silver Islet", a terrific storm broke over the cape. The White Men were drowned and the Sioux scout was found drifting in his canoe in a crazed condition.
A most extraordinary thing happened during the storm. Where once was a wide opening to the bay, now lay what appeared to be a great sleeping figure of a man. The Great Spirit's warning had come true and he had been turned to stone.
Today, a partly submerged shaft to what was once the richest silver mine in the northwest, can still be seen. White Men have repeatedly attempted to pump out the water that floods in from Lake Superior, but their efforts have been in vain. Is it still under the curse of Nanna Bijou, Spirit of the Deep Waters? Perhaps...who can tell?
To log this earthcache you must email me the answer to the following question: From what you can see of the Sleeping Giant is it made up of mesas or cuestas. Also don't forget to take a picture of your favourite cacher or GPS with the Giant in the background and post it with your log.
Additional Hints
(No hints available.)