Possible parent rocks of gneiss are granite, shale, gabbro or diorite. Some rocks metamorphose, or change, from one particular kind of rock, but gneiss forms from one of several types. Another name for the parent rock is the protolith.
A:Salt, or sodium chloride, is a non-renewable resource. A resource is defined as renewable only if it is self-replenishing. While new salt is being formed by natural processes in the earth, the timescale for that formation is too vast for salt to be considered self-replenishing in terms of human use.
A:While there's no such thing as petrified rock, petrified wood is fossilized wood. According to YourGemologist, there is no wood actually left in petrified wood, only rock that takes the same form and shape of the wood.
A:Mountains are found on every continent in the world. Though there are some single-standing mountains, they are most often found in groups known as mountain ranges. Some mountains arise from volcanic eruptions, while others have been formed by the shifting of tectonic plates. Thus, mountains are commonly seen at the intersection of tectonic plates and in places where the Earth's crust is relatively thin.
A:The average depth of Lake Huron is approximately 195 feet, but its deepest point reaches 750 feet below the surface. This massive body of water is located between Michigan and Canada, stretching 206 miles long and 183 miles wide.
A:Rock composed of layered bands of sediment is called sedimentary rock. Erosion creates sand, clay, silt and other sediment. Sediment builds up, and with the passage of time, the layers are compacted and cemented together to form sedimentary rock.
A:A plateau is formed by a process of geological uplift, either due to the collision of continental plates, pressure from magma below or the burial of land by volcanic lava and ash flows, resulting in a high, flat surface. These are very similar to processes that give rise to mountains and mountain ranges. The only major difference is that a plateau is flat while mountains are peaked.
A:At the beginning of the 1900s, the Frasch process of mining sulfur became the most popular way of extracting it. However, by the end of the 1900s, most sulfur has been manufactured by recovering it from petroleum and gas.
A:Absolute dating is a method of determining the specific date of a paleontological or archaeological artifact or location based on a specific time scale or calendar. Scientists base absolute dating on measurable physical or chemical changes or on written records of events.
A:The fossil record refers to the collection of physical and research evidence that paleontologists and geologists have used to prove the veracity of evolutionary theory. The physical evidence in the fossil record comes from fossilized remains of prehistoric animals.
A:Chemical weathering is the process by which a material breaks down into its component elements through the action of a chemical agent. This type of weathering requires precise temperature conditions and the presence of a chemically-laden fluid. Substances capable of causing chemical weathering include water and acids.
A:The Encyclopedia of Arkansas explains that commercial mining of quartz is rare and occasionally consists of the use of explosives to first expose the quartz, followed by the operation of small hand tools such as chisels and rock picks to extract portions of the mineral from a quarry. Quartz is quite sensitive to temperature changes, so miners prefer not to use explosives unless absolutely necessary.
A:The market value of topaz varies greatly, ranging from approximately $8 to $749 per carat as of September 2014. Its worth is determined by a number of factors such as weight, color, clarity, cut and shape. A gemologist must appraise the gem to provide an exact estimate.
A:Granite has a coarse to very coarse grained texture. It is typically granular and can be porphyritic with well-shaped large crystals of feldspar. Its structure contains cavities wherein well-formed crystals project.
A:Real silver is identified by its sound, its lack of magnetic qualities and by its ability to conduct heat. For instance, when tapped together, two silver coins emit a high, clear tone. The bell-like ring continues for a second or two.
A:To turn copper green, create a verdigris paina by rubbing the metal with a vinegar and salt solution. Before you begin, gather some steel wool, a bowl, paper towels, dish soap, baking soda and a finishing wax or lacquer.
A:Shale forms from the pressure of layers of sediment compressing bits of silt that settle into the clay on the bottom of bodies of water. The compressed clay and silt become shale over time. Shale is a sedimentary rock.
A:Metamorphic rocks are used for roofing material, decorative gardening stone, the base for snooker tables, building material, sculpture material and paving material. Metamorphic rocks come in three different types: slate, marble and schist.
A:According to the National Park Service, sedimentary rock forms when mud and sand are deposited into layers on the earth’s surface and later buried. The buried mud and sand is compacted by the weight of the overlying layers of earth until they harden and form solid rock.
A:Many geologists classify a landform as a mountain if it is at least 300 meters or more above its surrounding topography. Mountains have steep sloping sides, rounded or sharp ridges, and a peak or summit. Hills are not as high or steep, but they do typically have an obvious summit.