To log this Earthcache, you will NOT be looking for a typical geocache container (in fact, there IS no container to find). Rather, to prove you were here and learned something you'll need to find the answers to the given questions (found below as well as at the end of this description), which you will then email me, the owner (this is the same process for ALL Earthcaches).
So go ahead and log your experience while here, submit photos, etc., but email your answers to me (not in your visit log) to get credit for "finding" this cache. If it seems too complicated, don't sweat it too much (as long as I can see that you made an honest effort to answer all of the questions, that is fine). Remember that the purpose of this is to learn something, and most importantly, to have fun! Also, feel free to email me with any questions you may have, I'd be happy to help.
Special thanks goes to Teresa Frampton, the Outdoor Rec Planner at the BLM office in Fillmore, who generously gave permission for this earthcache to be created and placed.
To log this cache, use the info below, your surroundings, observations and logic while at the given coordinates to answer two of the following questions. Email me the appropriate answers (please don't post them in your log, or per Earthcache guidelines your post will have to be deleted), and feel free to post photos / describe your experience. Most of all, have fun!
Answer the following:
- As you looked around, what type of igneous stone / rock did you observe (as mentioned in this geocache description)? Did you find any other type of igneous rock described here (if so, describe)?
Next, complete at least one (1) of the following and answer the questions (email me the answers)
- (Option A): Find some rock with sunstones embedded inside it. Describe the rock as well as the sunstone crystals you found, such as size, color, etc.
OR
- (Option B): As you explore the knoll and surrounding flats, find several sunstone crystals. Describe their size, color, etc.
If you would like, you may complete the following:
- (Optional): Feel free to take and post (to either me, and / or on the main logbook) a picture of yourself and / or the knoll
Introduction
As you look about the area, you may notice that there is lots of evidence of volcanic activity in this area. As you look further away, you may notice other nearby sites that are indicative of this as well. Sunstone Knoll, as this area is known, lies in the NW part of the Black Rock Desert, a volcanic field that covers over 2,700 square miles, from Topaz Mountain to the NW, across to Pahvant Butte, a dormant volcano that erupted some 15,000 years ago to the East, as well as Tabernacle Hill, another dormant volcano known for its fantastic lava tubes to the SE.
Image: Here is the Tabernacle Hill crater, with Pahvant Butte seen in the distant background, in the Black Rock Desert.
NOTE: If you are interested, you may collect sunstones while you visit this site, free of charge. I recommend you bring a hammer, rock chisel, safety glasses, and lots of water. Simply make sure to obey the following BLM Rules
Sunstone Knoll
Our focus today however is here, at Sunstone Knoll. The volcanic activity here is a bit older than some areas of Utah, and lasted for roughly 1 million years, from 1.6 million years ago till about 750,000 years ago during the Pleistecene Era. It originally began as volcanic vents, which erupted during this period, letting hot magma reach the surface, which cooled and formed the outcropping of rocks you can see here.
Image: Here is Sunstone Knoll as seen from SR-257 (source: Kent Hunt, Google Maps)
Types of Rocks Formed:
There are many types of volcanic rock that are produced, depending on the type of vent where it is made, etc. See the descriptions below, and then decide for yourself which type of rock(s) may have formed here at Sunstone Knoll.
There are two main types of volcanic rock: intrusive igneous rocks, which are formed when magma cools slowly below the surface. The other type is extrusive igneous rock, which forms when magma erupts on the surface and cools more quickly. Each of the following igneous rock types fits into at least one of these more general categories:
Pumice: is an extrusive, light-colored vesicular (i.e. full of little air bubbles) igneous rock. It forms through very rapid solidification of the lava. The vesicular texture is a result of gas trapped in the melt at the time of solidification. See example below:
Basalt is a dark-colored, fine-grained, igneous rockcomposed mainly of plagioclase and pyroxene minerals. It most commonly forms as an extrusive rock, such as a lava flow, but can also form in small intrusive bodies, such as an igneous dike or a thin sill. It is quite common, found on Earth, Mars and even the Moon! See below for an example:
Diorite is a coarse-grained, intrusive igneous rock that contains a mixture of feldspar, pyroxene, hornblende, and sometimes quartz. It has a composition between that of granite and basalt. It usually occurs as large intrusions, dikes, and sills within continental crust. Picture below:
Rhyolite is a light-colored, fine-grained, extrusive igneous rock that typically contains quartz and feldspar minerals. Topaz Mountain is famous for its rhyolite deposits, which contain red beryl and topaz. See below for picture:
Scoria is a dark-colored, vesicular, extrusive igneous rock. The vesicles are a result of trapped gas within the lava at the time of solidification. It often forms as a frothy crust on the top of a lava flow or as material ejected from a volcanic vent and solidifying while airborne. Example is shown below:
Obsidian is usually an extrusive igneous rock that forms when molten rock material cools so rapidly that atoms are unable to arrange themselves into a crystalline structure. It is an amorphous material known as a "mineraloid." The result is a volcanic glass with a smooth uniform texture that breaks with a conchoidal fracture. See photo:
Note: There are certainly other types of volcanic rocks, but these should suffice for this purpose
What is Sunstone?
Sunstone is a transparent, yellowish labradorite (a plagioclase feldspar mineral) found originally as crystals formed in the cavities of these volcanic rocks. It is a somewhat rare stone, found in Utah only here, as well as Sweden, Norway, and in several locations in the U.S. It is even the official gemstone of Oregon! Here at the knoll, as the stone they are embedded in weathers, many crystals are carried down the hillside. The easiest places to find them are on the slopes and flats around the knoll, where they can be easily found on a sunny day, or at night with a flashlight, as the light relects off of their shiny surfaces.
Some believe that sunstones, like other gemstones, have special properties beyond their beauty. For example, sunstone is believed to increase motivation and creativity. They can also vary quite a bit in color, although the ones in Utah tend to be orange - yellow - clear. Below shows some examples of cut sunstone:
In its natural state, sunstone tends to not be quite as shiny. Below are some examples of sunstones as can be found at Sunstone Knoll:
Sources: www.geology.com, www.geology.utah.gov, and as noted
In conclusion, remember: to log this cache, use the info above, your surroundings, observations and logic while at the given coordinates to answer two of the following questions. Email me the appropriate answers (please don't post them in your log, or per Earthcache guidelines your post will have to be deleted), and feel free to post photos / describe your experience. Most of all, have fun!
Answer the following:
- As you looked around, what type of igneous stone / rock did you observe (as mentioned in this geocache description)? Did you find any other type of igneous rock described here (if so, describe)?
Next, complete at least one (1) of the following and answer the questions (email me the answers)
- (Option A): Find some rock with sunstones embedded inside it. Describe the rock as well as the sunstone crystals you found, such as size, color, etc.
OR
- (Option B): As you explore the knoll and surrounding flats, find several sunstone crystals. Describe their size, color, texture, etc.
If you would like, you may complete the following:
- (Optional): Feel free to take and post (to either me, and / or on the main logbook) a picture of yourself and / or the knoll
This cache was created by an
