Geology Terms

Ash-fall tuffs: Tuffs of ash that are blown into the air as a result of many small volcanic explosions.

Ash-flow tuffs: Lava that quickly transforms into droplets (volcanic ash) as a result of a grand eruption.

Caldera: A volcano that emits magma through multiple openings in series of small eruptions. Once the pressure inside its magma chamber becomes too great for the overlying rock to withstand, the caldera erupts and explodes, leaving a large crater.

Drill core: Sample of minerals used for a study.

Erosion: The movement and eventual deposition from one spot to another of nature by natural agents, such as water.

Extrusive rock: Igneous rock that forms from lava cooling quickly under relatively cool temperatures above Earth’s surface, forming small crystals.

Flood scar: The remains of a flood that remove the surface layers of the earth, allowing for study of subterranean rock.

Freeze-thaw weathering: A type of physical alteration in the rock in which water in cracks of rock freeze, expanding and thus breaking the rock.

Granite: A type of igneous rock formed from magma that never reached the surface. Lava has cooled beneath the surface of the earth, forming large crystals.

Igneous rock: Rock formed by the cooling of magma. Examples of igneous rock in Missouri include granite and rhyolite.

In situ: “In place.” Refers to if the rock’s current location is the same as the rock’s place of origin.

Intrusive rock: Igneous rock that forms from magma cooling gradually under relatively warm temperatures below Earth’s surface, forming large crystals.

Lava: Molten rock above the surface of the earth.

Lava flow rock: Molten rock formed by volcanic eruption.

Lichen: A mossy organism that grows on rocks, walls, and trees that contributes to the weathering of their hosts.

Magma: Molten rock below the surface of the earth.

Metamorphic rock: Rock altered by extreme heat or pressure. In Missouri, metamorphic rocks are found less often than igneous and sedimentary rocks.

Mineral: A solid formation consisted of one specific type of inorganic substance.

Missouri Division of Geology and Land Study: An organization that serves to make geologic information publicly available.

Pyroclastic flow: A mixture of ash and gas that flows down a volcano.

Rhyolite: A type of igneous rock. Lava has cooled above the surface of the earth.

Rock: A solid formation consisted of more than one type of minerals. May contain organic materials.

Sedimentary rock: Rock formed by the deposition of sediment (created by erosion, typically by water) in another location. Limestone, sandstone, and dolomite are examples of sedimentary rock in Missouri.

Unconformity: Gaps in the geological record caused by the movement of tectonic plates.

Volcanic ash: Fine, gritty piece of rock formed from small forcibly exploded lava droplets.

Weathering: The breaking down of natural and artificial surfaces as a result of contact with water, organisms, and Earth’s atmosphere. Not to be confused with erosion, as weathering occurs in one place (in situ).

Botany Terms

Alternate (leaves): Leaflets positioned alternately across from each other on the stem of the leaf.

Biotic potential: The highest possible yield of a species in ideal conditions.

Bract: A modified leaf, contains the fruit/seeds of the plant.

Deciduous: Trees that shed their foliage annually.

Evergreens: Trees that keep their foliage year-round. 

Lanceolate (leaves): Long and thin, slightly wider in the middle, with pointed tips.          

Midrib: The main vein of a leaf, located along each leaf’s midline.

Oblique (leaves): Asymmetrical, inclined unparalleled leave base.

Oblong (leaves): Elongated, rectangular leaves.

Opposite (leaves): Leaflets positioned directly across from each other on the stem of the leaf.

Palmately lobed: Palmately veined leaves whose individual veins, essentially, act as individual midribs for individual lobes (pointier than pinnately veined leaves).

Palmately veined: Leaves whose veins all stem from a common point on the midrib.

Pinnately lobed: Pinnately veined leaves whose individual veins, essentially, act as individual midribs for individual lobes (rounder than palmately lobed leaves).

Pinnately veined: Leaves whose veins each stem from a different point on the midrib and form in an alternating pattern.

Serrate (leaves): Saw-toothed; with asymmetrical teeth pointing forward.

Sexually dimorphic: A species that has differentiating body forms between genders.

Transplanting: Relocating long-lived plants to an area closer to a settlement to make harvest more convenient.

Whorled (leaves): Leaflets positioned in a spiral like pattern around the stem of the leaf.


Zoology Terms

Anticoagulant: A substance that limits the clotting of blood.

Calcar: A cartilage structure that extends from the ankle on a bat to the tail.  It provides support for the tail membrane.

Chiroptera: The order of mammals that includes all bats.  Etymology: “hand-wing.”

Dorsal: Relating to the back.

Ectoparasite: A parasite that lives on the outside of the host.

Extirpated: Extinct in a certain area but present elsewhere.

Flyway: The route that birds take during migration.

Gestation period: The period from conception to birth. 

Hibernaculum: A location used for hibernating.  Examples include caves, mines, and buildings.

Invasive species: An organism that may or may not be native to the environment in which it is found. Invasive species have negative impacts on that environment by outcompeting other organisms for space and nutrients. For example, Asian clams, zebra mussels, and bush honeysuckle are all invasive species (and non-native) in Missouri. Many early successional stage species, such as black-eyed susan, are native to Missouri and can be weedy and take over an area easily.

Megafauna: Large animals of a particular region, habitat, or geological period.

Migration: Seasonal travel of birds from the north to the south, for breeding, escaping the cold, and finding food. Other organisms that migrate include monarch butterflies, deer, elks, wildbeests, snakes and even whales. 

Niche construction: Organism-driven environment modification.

Non-native species (also known as Exotic Species): An organism that is not native to the environment in which it is found and may act as an invasive species (see above definition) or be beneficial by providing food and habitat for native animal species. 

Resilience: The capacity of species to sustain high annual harvest yield.

Resistant species: Species whose population is almost impossible to be driven below a ‘‘security density’’ level if given suitable habitat.

Ventral: Relating to the underside, or belly.