A type of mudflow that originates on the slopes of volcanoes when volcanic ash and debris becomes saturated with water and flows rapidly downslope.
Very thin layers of less than 1 cm thickness.
Downslope movement of rock, soil, and mud.
Present and historical uses of land, such as for agriculture, mining, recreation and grazing.
Magma that reaches the Earth's surface through a volcanic eruption. When cooled and solidified, forms extrusive (volcanic) igneous rock.
A metamorphic mineral that forms only under very high pressure. It is a calcium aluminum silicate and usually forms microscopic crystals.
A dating method that uses the growth rate of certain lichen species as an indicator of the age of the surface the lichen is growing on.
A sedimentary rock made mostly of the mineral calcite (calcium carbonate). Limestone is usually formed from shells of once-living organisms or other organic processes, but may also form by inorganic precipitation.
A mineral composed of iron oxides and water. Rust. Very common in many rocks after weathering at the Earth's surface. Imparts brown or yellow colors to many rocks.
A linear (relatively straight) topographic feature or features such as a fault, line of dense vegetation, or a chain of aligned volcanoes.
Parallel arrangement of elongate minerals or groups of minerals. To envision lineation, imagine packages of spaghetti or pencils.
"Made of stone". Refers to pieces of rock within other rocks such as tuff and conglomerate.
The conversion of loose sediment into solid sedimentary rock. Several processes, including compaction of grains, filling of spaces between grains with mineral cement, and crystallization act to solidify sediment.
The outer layer of solid rock that includes the crust and uppermost mantle. This layer, up to 100 kilometers (60 miles) thick, forms the Earth's tectonic plates. Tectonic plates float above the more dense, flowing layer of mantle called the asthenosphere.
A wind-blown deposit of sediment made mostly of silt-sized grains.
The appearance of the reflection of light from the surface of a mineral. Luster is described as metallic, glassy, dull, etc.