Limestone:
Four hundred million years ago North America was a virtually lifeless landmass located near the equator. As the earth's climate stabilized and large glacial formations went through a process of melt off and retreat, a substantial rise in water levels occurred worldwide. A shallow, warm salt-water sea developed and covered major portions of North America. This warming gave to ideal conditions for marine life to thrive and develop. Brachiopods, Trilobites, Crinoids, Conodonts, Corals, Stromatoporoids and many other creatures soon inhabited this vast sea as time progressed. This sea bottom was then covered with the skeletal remains (Calcium Carbonate CaCO3) of these ancient marine creatures and sediment derived from erosion of the landmass itself. This sediment, under pressure, heat and time, soon transformed into Limestone.
Typically, in a completely pure state, limestone is white or an off white color. When impurities such as clay, sand, organic remains or iron oxide enter into the formula, a wide range of colors can then be exhibited such as yellow, green, brown or pink. Limestone makes up about 10% of the total volume of all sedimentary type rock found worldwide. With the mountain building processes (orogeny), limestone alters into Marble. A process called metamorphism.
Sandstone:
Sandstone is a sedimentary rock composed mainly of sand-sized minerals, rock grains and/or organic material. Most sandstone is composed of the most common minerals found in the Earth's crust, Quartz and Feldspar, making it Felsic in nature. The formation of sandstone involves two principal stages. The first is sedimentation. This occurs when sand settles out of suspension (ceases to be moved along by means of water flow or wind) and accumulates. The second stage begins when the accumulated sand and mineral mix becomes compacted by the pressure caused from overlying deposits. Cementation then occurs by the precipitation of minerals within the pore spaces between sand grains. The most common cementing materials are silica, calcium carbonate and/or clay.
As with sand itself, Sandstone can come in a variety of colors. The most common colors being tan, brown, red, pink or yellow. Sandstone is smooth but sandy/grainy to the touch. Since Sandstone beds often form highly visible topographic features, certain colors of Sandstone have been strongly identified with certain regions, such as the Iron rich Sandstone of the Red Rock Canyon National Conservation Area outside of Las Vegas, the bleached (by precipitation) white Sandstone of Zion National Park in Utah, the orange Sandstone of the Grand Staircase (Escalante National Monument) in Utah, the Limonite infused yellow Sandstone of Sussex England, the Glauconite (Mica) infused (green) Lion Mountain Sandstone of Texas, the Manganese based purple Sandstones of the Valley of the Moon in southern Jordan and the browns of the Torrey Pines State Natural Reserve in California.
With heat and compression (cause by tectonic forces), Quartz bearing Sandstone alters into Quartzite, a metamorphic type rock.
Granite:
Granite is an igneous type rock that forms below the Earth's surface (intrusive). Being below ground forces slower cooling, giving time for the crystals within the magma to grow in size. These crystals soon become large enough to be seen with the naked eye (phaneritic) and rough to the touch.
Granite is composed mainly of Quartz and Feldspar (felsic) with minor amounts of Mica, Amphiboles and/or other minerals. Granite can be pink to gray in color depending on the amount of these other minerals contained within. Granite, by definition, contains at least 20% Quartz and 35% Alkali Feldspar. It tends to form in tors (large, free-standing rock outcrops) or rounded massifs (sections of the planet's crust marked by faults or flexures). Granite is usually found in continental, and not in the oceanic plates of the Earth's crust.
Gneiss:
Gneiss is formed by metamorphic processes (heat and pressure) from pre-existing rock (protolith). These pre-existing rock formations were either igneous or sedimentary in nature. Metamorphism is described as a change in minerals or texture without the protolith becoming liquid (magma). Gneiss is composed of layers of sheet-like structures (foliated), generally alternating darker and lighter colors(Gneissic banding) of medium to coarse crystals, making it quite rough to the touch. These bands generally range in thickness from 1 mm to several centimeters. Darker bands contain more mafic minerals (Magnesium and Iron) and the lighter bands contain more felsic minerals (Silicates, such as Silicon, Oxygen, Aluminum, Sodium, and Potassium). Gneiss does not contain large quantities of mica, chlorite or other platy (flaky layer) minerals. Gneisses that are metamorphosed igneous rocks are termed as Granite Gneisses, Diorite Gneisses, etc. depending on their original composition.
Approximately 75 percent of rock found within continental land surfaces is sedimentary in nature. The remainder is mostly igneous with very little being metamorphic. Most oceanic floor rock is igneous in nature with the majority being Basalt, a heavier than Granite rock.
The coordinates listed will bring you to a scenic overlook which can only be entered via East bound Pioneer Parkway (SR 89A). Located at the coordinates you will find 4 large rocks. They are of different colors, textures and mineral makeup. Number them 1 through 4 with 1 being to your left. Email your answers to the questions to me using the link in my profile only. Be careful. The answer to each question could possibly be 0, or any number up to 4. If your answers are not received by me, your log might be deleted. Photos are accepted and appreciated of the surrounding area but any taken of the 4 rocks will be deleted. You do not have to wait for confirmation from me before logging this cache as completed. Most of all……learn……and enjoy the view.
1. How many of the 4 rocks are Limestone?
2. How many of the 4 rocks are Granite?
3. How many of the 4 rocks are Gneiss?
4. How many of the 4 rocks are Sandstone?
5. Which of the 4 rocks is sedimentary?
6. Which of the 4 rocks is igneous?
7. Which of the 4 rocks is metamorphic?
8. What causes rock #2 to be the color that it is?
9. What is the altitude according to the information plaque?