Wegener-ing Around (Continental Drift Evidence)
Alfred Wegener used this specific geometric boundary, rather than the visible sea-level shoreline, to perfectly match South America and Africa together like puzzle pieces.
What is the continental shelf? (or slope)
This is the core tectonic process that continuously creates fresh, brand-new oceanic crust at underwater mountain chains.
What is seafloor spreading?
This is the fundamental, grand theory stating that Earth’s rigid outer shell is cracked into fragments that constantly jostle past one another.
What is plate tectonics?
This property describes how marine magnetic anomalies run relative to a mid-ocean ridge axis, framing a perfect mirror image across both sides.
What is parallel and symmetric?
This is the basic boundary type where two structural plates slide laterally and horizontally past each other without generating any volcanoes.
What is a transform boundary?
This is the name Alfred Wegener gave to the colossal, ancient supercontinent that existed before it fractured and drifted apart.
What is Pangaea?
To keep our global dimensions stable, the rate at which new crust spreads must perfectly mirror the rate of crust destruction at these zones.
What are subduction zones?
If you live on a coastline that is safely tucked away inside a stable plate interior with no active faults or volcano hazards, you reside on this type of margin.
What is a passive margin?
Navigational compasses point to magnetic north rather than true geographic north; the angular difference between these two paths is known as this.
What is declination?
This massive California plate boundary line is a classic example of a transform fault slashing right through continental crust.
What is the San Andreas Fault?
These linear scratches or gouges left on bedrock provided Wegener with undeniable proof that glaciers once covered tropical regions like India and Africa during the Late Paleozoic.
What are glacial striations?
Volcanic activity driving seafloor spreading doesn't hide out in the deep flat plains; instead, it is highly concentrated directly along these massive submarine mountain ranges.
What are mid-ocean ridges?
This is the specific structural term for individual fragments of rigid lithosphere that glide across the soft layer beneath.
What are tectonic plates?
In super-hot magmas, magnetic dipoles bounce around randomly; they can only lock into place once the rock cools below this crucial point.
What is the Curie point? (Accept: locking temperature)
Since we live right here in Bakersfield, we can rest assured knowing our school is firmly anchored on this major tectonic plate.
What is the North American Plate?
Abundant equatorial swamps during the Late Paleozoic left behind thick layers of decayed plant matter, which turned into this valuable fossil fuel now mined in North America.
What is coal?
If you are drilling down close to a mid-ocean ridge axis, you can expect the overlying layer of marine sediment to look like this in terms of thickness and age.
What is thin and young?
These flat, massive, and virtually featureless geographic plains occupy the vast majority of the deep ocean floor between ridges and trenches.
What are abyssal plains?
These strong positive magnetic anomalies occur when the frozen magnetic orientation in seafloor basalt matches this modern state.
What is normal polarity?
Transform boundaries don't randomly cut ocean basins; they exist specifically to connect ridge segments and accommodate movement across this geometrical shape.
What is a sphere?
American geologists flatly rejected Wegener's brilliant continental drift hypothesis for decades because he completely lacked this vital scientific explanation.
What is a valid mechanism for how continents move? (Accept: He didn't know how they plowed through ocean crust.)
When basaltic magma hits icy seawater at a mid-ocean ridge axis, it rapidly chills out into these distinct, rounded glass-capped formations.
What is pillow basalt?
Active continental margins, like the Pacific coast of North America, are easily identified by having narrow continental shelves that drop straight down into these feature models.
What are trenches or active fault systems?
The width of alternating magnetic stripes mapped out on the seafloor is directly proportional to this specific timeframe.
What is the duration of a magnetic chron?
Along active transform segments on the ocean floor, earthquakes will only disrupt this precise, limited section of the fracture zone.
What is the portion between the two ridge axes?