Limestone is formed from the decay of marine life. When they die, they sink to the bottom. Now, all living things must have phosphorous as it makes up DNA. When the animal dies, the phosphorus decays as well and over time, forms a hard layer of rock we know as limestone. Limestone gets its distinctive color from the calcium in the rock from other parts of decaying organic mater. Over millions of years, this limestone has lifted out of the ocean from below sea level, to this site at a rate of about two millimeters every year.
Limestone forms from phosphorus rich dead organic matter that falls to the bottom of lakes and oceans. Overtime, limestone is brought to the surface and looks like this:
So how did this limestone get a few hundred feet above sea level and why is it so far inland? Well, the California Costal Ranges used to be underwater. Due to the many faults in Southern California, some of these areas have literally lifted out of the ocean. This is due to the fact that faults create tension on the land between other faults. There is the Newport-Inglewood fault just off shore of Laguna Beach which creates tension between the Elsinore Fault near Lake Elsinore. Because oceanic crust is thiner, it's the first to give way creating mountains and uplifting the land. That's how this limestone came to this location, in the hills of Laguna Beach.
TO LOG A FIND ON THIS CACHE YOU MUST GIVE ME THE CORECT ANSWERS BEFORE YOU LOG A FIND. YOU CAN CONTACT ME THROUGH MY EMAIL OR THE GEOCACHING MESSAGE CENTER. ANY INCORRECT ANSWERS WILL RESULT IN A DELETED LOG
1. "Laguna Beach - Limestone" on the first line of your email AND list all geocaching names of your party so I can match your answers to them. Note, this IS cheating as only the person who sent their answers has learned something, while the others get a "free ride". It's not fair to others. If you all want to learn something, I would prefer each cacher send me individual emails in the spirt of earthcaching.
2. Describe the (a) texture AND (b) colors of the limestone at this location.
3. Why do you see different colors of limestone here?
4. Explain the erosion process here AND how it has effect the limestone.
5. Look very closely for any evidence of fossils. Explain what you see or don't see. Why do you think this is the case?
6. Would you expect to find fossils here if you broke open a sample of this limestone?
Works Cited
http://geology.com/rocks/limestone.shtml
http://www.sharkbay.org/geological_foundations.aspx