Copp's Quarry EarthCache

Rocklin was the principal granite-producing point in the Sacramento Valley.

Geology Lesson
Granite is a light-colored igneous rock with large grains running through it. It is slowly formed from magma deep beneath the Earth's surface. It is composed mainly of quarts and feldspar with trace amounts of mica, amphiboles, and other minerals. Granite often comes in various shades of red, pink, gray, and white. Granite is the most common igneous rock found on the Earth's surface. The large crystals and grains seen within the rock are evidence that it cooled slowly below the Earth's surface over a very long period of time. As different parts of the stone cool separately, these grains vary in size.
Granite is often called a plutonic rock because it formed deep within the surface. There are two theories revolving around the exact process that cause granite to form.

1. Magmatic theory - supporters of this theory believe that granite formation is associated with mountain ranges which typically follow the edges of continents where one plate is being subducted (wedged under another layer). Deep beneath the continental edge, friction and pressure cause large zones of subduction which generates enough heat to melt large amounts of rock. This melted rock, or magma, rises toward the surface in large plutons. It does not rise all the way to the surface, but instead slowly cools. Over time, erosion brings these plutons closer to the Earth's surface.
2. Ultrametamorphic theory- this theory states that granite is not formed from magma but is sedimentary rock that was melted and recrystallized. In essence, the rock is recycled and during this process granite is formed.

Copp's Granite Quarry History
After the initial rush from the goldfields began to subside, people started looking at alternative sources of income. In 1861, after seeing numerous granite blocks above ground in Rocklin, Mr. Hathaway opened a quarry to supple the foundation blocks for the new California State Capitol. Since then, many other quarry companies (over 60) came to Rocklin to begin stonecutting for many other projects including building tunnels for the railroad, US Mint in San Francisco, the Bank of Italy, Pearl Harbor, and the Campanile in Berkeley...to name just a few. Today Copp's Quarry is a two-acre lake bordered on three sides by 40 foot tall granite walls. In the 19th century this was one of Rocklin's most productive granite quarry mines. Opened in 1884 by Massachusetts native Ruben Copp, it provided granite for buildings from Stockton to San Francisco. Copp sold the quarry to the Pacific Granite Company in 1889. The quarry was located very close to a railroad spur to make it easy to transport the granite. In 1912, a very heavy train rolled past and due to the weight part of the quarry caved in. Copp's Quarry closed in 1915 during a large-scale stonecutter's strike. This strike forced the closure of more than half of Rocklin's quarries. Ruben Copp died in 1916.

To log this cache:

In an email please answer the following questions based on your personal observations:
Do not post answers as part of your log, encrypted or otherwise, or it will be deleted!

1. How many people in your party?
2. What are the prominent colors that make up the quarry walls?
3. Describe the granite walls. Are they look fairly smooth or jaggedly cut?
4. The quarry is on the east side of the paved path. Looking west, is there any evidence of granite outcrops?

• Optional: take picture of yourself at the confluence

• _{Placer Herald}
• _{Rocklin Historical Society}
• _{City of Rocklin}
• _geology.org
• _wikipedia

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