Realm
Interior & Plates
A layered, restless shell
Crust to inner core, then the plates that carry continents. Boundaries write mountains, trenches, and faults.
Earth’s interior
A cut apple is a bad model of Earth: the ‘skin’ would be thinner than the apple’s, and the outer core is liquid metal.
Plate boundaries
Holderness loses metres of till each year; the Himalaya gain millimetres of rock. Both are plates doing different jobs at their edges.
Continental drift
250 Ma the pieces fit. Fossils agree. The ocean is not a static floor continents plough through.
Hotspots
Hawaii and Yellowstone are holes the plate is sliding over — not the same as a plate edge.
Seafloor spreading
Magnetic stripes are a tape recorder. New crust at the ridge, older away.
Folds and faults
Rocks bend or they break. Anticline, syncline, then the three fault slips.
Isostasy
Scotland is still rising after the ice. Hudson Bay is still rising too. The crust floats. Load it, it sinks. Unload it, it comes back.
Wilson cycle
The Atlantic is opening. One day it will close. The Caledonides and the Appalachians are an older ocean that already did.