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Great Rockin’ Combination; Earth Cache

A cache by GeoJoe-prosrocket Send Message to Owner Message this owner
Hidden : 11/07/2013
1.5 out of 5
1 out of 5

Size: Size: not chosen (not chosen)

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Geocache Description:

A great combination comes to life right before your very eyes.

Happy Caching!


GeoJoe-prosrockets is proud to say that I have earned GSA's highest level:

Please park only in the parking lot, respect the property and do not climb on the rocks.

This cache is located on the side of a parking lot at a local restaurant.

You can pull right up to the cache in your car.

This cache can be done after dark with the aid of your car headlights and a lamp post overhead.

It has been placed with the approval and permission of the restaurant owner.

This cache is handicap and wheelchair accessible. You are able to see everything from the parking lot.  The rock is up a curb and about 10 feet in, on the grass.

I hope you enjoy this beautiful and amazing structure.
As with all geocaches; please be careful and follow the GeoCachers Creed.

Xenolith: “rock fragment within an intrusive igneous body that is unrelated to the igneous body itself. Xenoliths, which represent pieces of older rock incorporated into the magma while it was still fluid, may be located near their original positions of detachment or may have settled deep into the intrusion, if their density is greater. Xenoliths can be contrasted with autoliths, or cognate xenoliths, which are pieces of older rock within the intrusion that are genetically related to the intrusion itself. The general term for all such incorporated bodies is inclusions. Xenoliths are usually reconstituted through the processes of contact metamorphism, in which heat and fluids cause mineralogic[sic] and chemical changes in the parent rock of the xenolith; a study of these changes can give information on the temperature and composition of the magmatic body.”

Got it? Good my explanation is done! Now just answer the questions below.

If you were like me when I read it for the first time, you might be scratching your head, jaw hanging open and looking at everyone else…thinking “WHAT?”

I will now attempt to explain it using something most of us can relate to.  To do this, you can either buy them to look at or just imagine them.  You will need 2 “Snickers” candy bars and a Chocolate truffle.  Take the truffle and split it in half so you can see inside.  Now take the candy bar and break off a piece for everyone in the car; do the same with the other candy bar. Let’s look at the candy bar; do you see how the creamy nugget, the delicious caramel and the wonderful peanut are layered and then covered by the hard milk chocolate outer shell?  OK now, everyone, eat one of the pieces of the candy bar…YUMMY! Use the other piece to notice how when you first look at this, it looked like one piece, but then you could see several distinctly different items there.  Different shapes and identifiably different ingredients are all layered together; this would be, if made from rock, a true xenolith.

Now look at the truffle.  The hard chocolate shell is made with the same material as the creamy chocolate center; they were just combined together at different consistencies and at different temperatures.  Again, if made of rock, this would be called an autolith or a cognate inclusion.
In appearance, there is usually a very distinctive difference in the rocks.

As always, a picture of you at the rock formation is fun, but it is not necessary to do this cache.

Please log your visit and send me an e-mail with the answer to the tasks and questions below.

Please DO NOT put the answers to your questions in the log.

-Estimate the size of the biggest rock in the group that contains a xenolith.  This would be done by multiplying the length, width and height together; your answer will be in cubic feet.

-How many large (bigger than 1ft by 1ft by 1 foot) xenoliths are in the biggest rock. Estimate the size of the xenolith(s) using the same formula above. Use to different sides of the rock to take the measurements and assume the xenolith(s) is rectangle; again your answer(s) will be in cubic feet

-Which rock do you think is the parent (older) rock; the lighter or darker rock.  Do you think the new rock pushed into or wrapped around the parent rock?  What makes you think that?

-Do you now think you could find a xenolith on your own?  I just found this one after doing an earth cache for one in another state just a few months ago; it was just sitting in a parking lot.  It may be a little harder to find another one as obvious and on this grand of a scale so close to you, but if you look real good, you can see this all around you; it is a very common occurrence that is rarely noticed.

Last, this is optional and not required; it is totally up to you:

Post a picture of you or a proxy at a junction of the xenolith.

Please follow the:

FTF HONORS GO TO..... gypc with an early morning 35F find!

Happy & Safe Caching!

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