Lake Ellen Kimberlite facts for kids
The Lake Ellen Kimberlite is a special type of rock found in the Upper Peninsula of Michigan. It's located about 10 miles (16 km) northeast of Crystal Falls. This rock is a kind of volcanic breccia, which means it's made of broken rock pieces cemented together.
Scientists became very interested in the Lake Ellen Kimberlite because rocks like it can sometimes contain diamonds! In the 1980s, people thought this kimberlite might be where diamonds found in Wisconsin a hundred years earlier came from. This led to many companies exploring the area, hoping to find diamonds.
What is a Kimberlite?
A kimberlite is a type of igneous rock. This means it formed from hot, melted rock (magma) deep inside the Earth. Kimberlites are special because they come from very deep within the Earth's mantle. They often contain rare minerals and sometimes even diamonds!
The Lake Ellen Kimberlite formed about 180 million years ago. This was during the Mesozoic Era, a time when dinosaurs roamed the Earth! The melted rock pushed its way up through older volcanic rocks, creating a pipe-like shape.
Discovery and Exploration
The Lake Ellen Kimberlite was first found in 1971. Workers were building a logging road when their bulldozers uncovered some unusual-looking rocks. Most of the kimberlite is hidden under glacial till, which is a mix of clay, sand, and rocks left behind by glaciers.
Scientists used a special tool called a magnetic survey in 1956. This survey helped them map out the area. It showed a large, oval-shaped area about 590 feet (180 meters) long and 390 feet (120 meters) wide. This oval shape likely shows how big the kimberlite pipe is underground.
Looking for Diamonds
The Lake Ellen Kimberlite is a popular spot for "rock hounds." These are people who love to search for interesting rocks and minerals. They can easily find special minerals here that are often found with kimberlites. These minerals are called "indicator minerals." They include pyrope (a type of garnet), magnesian ilmenite, and chrome diopside.
While these indicator minerals are common, most of them are not large enough or good enough quality to be used as gemstones. Even though there was a lot of excitement about finding diamonds in Michigan and Wisconsin, no diamonds valuable enough for commercial mining have been found yet.
Images for kids
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Typical weathered kimberlite from the Lake Ellen occurrence
