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: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:The molecular structure of a diamond makes it hard, as diamonds are comprised of carbon atoms linked closely together in a lattice structure. The atoms are linked tightly via covalent bonds wherein two atoms share an electron. A tetrahedral unit is composed of five carbon atoms, with one carbon atom sharing electrons with the other four. An extremely strong molecule is formed from the tetrahedral bonding of five carbon atoms.
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: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:According to the Oxford University Museum of Natural History, petrified fossils form when mineral deposits replace the bones of dead creatures inside hardened sediment. Over time, these deposits completely replace the remains, forming an image of the bones out of solid rock.
A:Most meteorites that fall to Earth come from the asteroid belt between Mars and Jupiter, where they formed during the early days of the solar system. Occasionally, collisions or gravitational perturbations send one of these objects hurtling toward the sun. If it approaches close to Earth, it may fall into the planet's gravity well.
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: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.
A:According to the U.S. General Services Administration, limestone is important because it is widely used in architectural applications for walls, decorative trim and veneer. It is less commonly used in making sculptures because of its porosity and softness.
A:The hardest natural mineral in the world is lonsdaleite, a rare mineral made of carbon atoms. This mineral can withstand up to 58 percent more stress than diamond, according to a report by Jessica Griggs of NewScientist.
A:Mine-cut diamonds are typically square or slightly oval and have a deeper crown and pavilion, or top and bottom, than modern stones. "Mine cut" does not refer to the place the diamond was faceted, but rather to its overall shape and brilliance.
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: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:Geodes are mostly found in deserts, volcanic ash beds and areas with limestone throughout the world. In the United States, common geode sites include Arizona, California, Iowa, Nevada and Utah. The most abundant geode sites in California are Riverside and Imperial counties.
A:Minerals are formed by organic processes, crystallization, melting and crystallographic transformations that occur in the mineral's solid state. Crystallographic transformations generally occur with a change in the pressure or temperature in the material surrounding the mineral deposit.
A:Coal reserves exist in every country in the world and on every continent except Antarctica. According to the World Coal Association, there are enough coal reserves to meet current demand for 112 years, but only enough oil and gas reserves to meet current demand for the next 46 and 54 years, respectively.
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: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.