Geology and Earth Science Terminology

Flashcards covering key geological terms and concepts related to tectonics, earthquakes, volcanoes, weathering, and hydrology.

Tectonite

Forms by significant stretching, precursor is any rock.

Marble

About 100% calcite, can be any color, intermediate to high grade, cooked limestone.

Greenstone

Fine to coarsely crystalline, usually contains chlorite, epidote, and plagioclase, formed by cooked basalt or gabbro, low to intermediate grade.

Soapstone

Scarce, talc-rich rock formed by cooked serpentinite.

Hypocenter

The actual underground location of an earthquake.

Epicenter

The land surface directly above the hypocenter of an earthquake.

P-waves

Primary waves that are push-pull in nature.

S-waves

Secondary waves that move in an up and down motion.

Love waves

Side to side waves that are surface waves.

Rayleigh waves

Rotational waves that travel along the surface.

Mercalli Scale

Measures the intensity of earthquake damage.

Richter Scale

Measures the amount of energy released by an earthquake, with a scale of 1 to 9.

Tsunamis

Walls of water generated by earthquakes, volcanic eruptions, or landslides.

Foreshocks

Minor earthquakes that occur before a major event.

Subduction zones

Regions where one tectonic plate dives below another.

Benioff zones

Zones of earthquakes in the subducting slab.

Hotspots

Large mantle plumes where volcanoes form at the surface.

Pahoehoe lava

Lava flow with a smooth or ropy top surface.

Aa lava

Lava with a sharp, jagged top surface.

Shield volcanoes

Large, low and broad volcanoes with quiet and effusive eruptions.

Stratovolcanoes

Large, steep-sided cones with alternating layers of lava flow and ash beds, known for explosive eruptions.

Calderas

Large holes left behind after a volcano collapses.

Maar volcanoes

Explosive holes formed when rising magma encounters groundwater.

Differential weathering

The process where softer rocks weather more quickly than harder rocks.

Mechanical weathering

The breaking of rocks into smaller pieces without changing their mineral composition.

Chemical weathering

Breakdown of rocks due to chemical reactions, forming new minerals.

Pedalfer soils

Soils rich in aluminum and iron, common in the eastern USA.

Mudflow

A down-moving slurry of water and fine-grained sediment.

Slump

A rotational slide along a curved surface.

Oxbow lakes

Cutoff meandering streams that form independent lakes.

Dendritic streams

Stream patterns that resemble tree branches.

Braided streams

Streams that interweave in a braid-like pattern.