Drummond Island is famous for its unique puddingstones, which are found in a limited area that includes this island and the neighboring shoreline of Lake Huron. Puddingstones are conglomerates, which is a type of rock made of many stones trapped inside a matrix of sediments. These rocks have a speckled appearance, similar to fruits floating in pudding.
How were Drummond Island Puddingstones formed?
Drummond Island Puddingstones were formed on the floor of ancient riverbeds about 2.2 billion years ago. Pebbles initially rested on the river floor and as the water ebbed and flowed, it successively washed layers of sand across these pebbles. This process interspersed the riverbed pebbles within the sand matrix. Over time, heat and pressure fused these sediments together into a single rock.
What makes Drummond Island Puddingstones Special?
Drummond Island Puddingstones display a unique combination of embedded stones and matrix:
Jasper is the most characteristic stone found in Drummond Island Puddingstones. Jasper is a bright red color that makes it easy to identify. In fact, these puddingstones are also commonly referred to as 'Jasper Conglomerate.’
Quartz is a whitish color, often with a translucent and crystalline appearance.
Black Chert is a dark grey to black rock that has an opaque and waxy appearance.
Quartzite forms the matrix of Drummond Island Puddingstones. Quartzite is created from metamorphized sand and takes on white, light grey, or slightly beige color. Drummond Island Puddingstones can vary considerably in the amount of matrix relative to pebbles fused inside the rock.
Logging Requirements
The posted coordinates will take you to an impressive specimen of Drummond Island Puddingstone. To log this Earthcache, send the answers to the following questions:
1. Estimate the percent of matrix relative to embedded pebbles in the rock (for example: 10% matrix, 90% pebbles).
2. Examine all sides of this rock. Is the matrix uniform or heterogeneous across the rock? Describe any patterns you see and why you think these may occur.
3. Examine the embedded pebbles. What are the two most frequently embedded stones in this rock?
4. Post a picture of yourself, or a personal item, at the stated coordinates in your log. PLEASE DO NOT INCLUDE THE ROCK IN THE BACKGROUND!
This Earthcache is located along Glen Cove Road. It is accessible with a two-wheel drive vehicle, but it may be a bumpy and muddy ride, depending on the time of year!
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