Drift-ing Into Puns (Early Theories)
This two-word term describes Alfred Wegener's radical 1912 hypothesis stating that Earth's continents are not fixed in place, but slowly crawl across the globe over vast spans of time.
What is continental drift?
This specific process describes how new oceanic lithosphere is continuously cooked up at volcanic underwater ridges and rolls outward like a giant conveyor belt.
What is seafloor spreading?
These incredibly deep, narrow depressions on the ocean floor mark the exact superficial boundary line where an oceanic plate bends downward into the mantle.
What are trenches? (Accept: deep-sea trenches)
This core unifying geological theory outlines the Earth’s rigid outer shell as a dynamic system of interacting, moving segments.
What is plate tectonics?
These sharp ocean-floor features consist of active transform faults connecting ridge segments along with their extinct, inactive extensions.
What are fracture zones?
This is the specific term used to describe the submerged, relatively shallow edge of a continent that Wegener used to achieve a much tighter geometric jigsaw fit between South America and Africa.
What is the continental shelf?
These linear, continuous submarine mountain chains represent the active divergent boundaries where magma continually wells up to form fresh oceanic crust.
What are mid-ocean ridges?
This two-word vocabulary term describes the curved mountain chains of explosive volcanoes that erupt on an overriding plate parallel to a subduction trench.
What are volcanic arcs?
Rather than a continuous sheet, the Earth's rigid lithosphere is fractured into these distinct, massive, separate pieces that move relative to one another.
What are plates? (Accept: tectonic plates)
These isolated, underwater volcanic mountains dotting ocean basins represent extinct hot-spot volcanoes that never successfully breached sea level.
What are seamounts?
Meaning "All Lands" in Greek, this massive vocabulary word describes the single supercontinent that conjoined all of Earth's major landmasses during the Paleozoic era.
What is Pangaea?
This term describes the narrow, steep canyon feature carving directly through the center of a mid-ocean ridge axis where stretching plates split apart.
What is a median valley?
This structural term is used to describe the single downgoing slab of oceanic lithosphere that is actively sinking into the hotter asthenosphere at a convergent zone.
What is a subducting slab? (Accept: subducting plate)
This specific vocabulary term stands for the solid, rigid outer layer of Earth comprised cleanly of both the crust and uppermost mantle.
What is the lithosphere?
This is the specific term for an underwater volcano that managed to peek above sea level, eroded flat by crashing waves, and subsequently subsided below the surface.
What is a guyot?
This specific term refers to the frozen orientation of ancient magnetic lines locked inside iron-bearing minerals, which geologists use to track past continental paths.
What is paleomagnetism?
This single-word vocabulary term stands for the alternating bands of strong and weak magnetic signatures recorded by ships passing over ocean floor basalt.
What are anomalies? (Accept: magnetic anomalies)
This is the precise geological term for the heavy material that stays attached to the bottom of oceanic crust and drags a subducting plate downward due to high density.
What is lithospheric mantle ballast?
Derived from Greek words meaning "weak sphere," this is the hot, ductile, and plastic layer of the mantle sitting directly beneath our moving plates.
What is the asthenosphere?
This specialized legal and economic vocabulary term describes offshore marine areas stretching 200 nautical miles in which a coastal country owns all underlying natural resources.
What is an Exclusive Economic Zone? (Accept: EEZ)
This compound term refers to the distinctive paths plotted on a map that trace out the changing position of Earth's magnetic poles relative to a fixed continent over time.
What is an apparent polar wander path?
This specific term defines a prolonged period of time during which the Earth’s magnetic field maintains a single, steady polarity direction before flipping.
What is a magnetic chron?
This structural term refers to a narrow, submerged marine basin that opens up right behind a volcanic island arc due to localized crustal extension.
What is a back-arc basin? (Accept: marginal sea)
This specific term identifies the precise depth line inside the Earth (~100 to 150 km) where rocks transition from cold, rigid behavior to hot, plastic flow.
What is the lithosphere-asthenosphere boundary? (Accept: LAB)
This specific term refers to a vertical fracture line where tectonic blocks slice past each other laterally with no vertical displacement.
What is a transform fault plane?