Presentation on theme: "Earths Crust Convection currents Continental drift – idea that continents have moved slowly to their current positions due to convection currents in."— Presentation transcript:
Continental drift – idea that continents have moved slowly to their current positions due to convection currents in the mantel. Pangea – the idea that the all land masses on earth were once a single large land mass.
Ocean floor spreading – theory that hot less dense material below Earths crust rises toward the surface at the mid-ocean ridges. Then, it flows sideways, carrying the seafloor away from the ridge in both directions. Convection current – unequal distribution of heat in the mantel causes a net movement in a circular motion.
The Earths CRUST is the outer most part of the Earths surface. Average 32 km thick Thickest point 70 km (in mountains) Thinnest point 8 km (under ocean)
Plate tectonic – theory that Earths crust and part of the upper mantle are broken into sections called plates. Lithosphere – all of the earths crust and part of the upper mantle. y/planets/earth/Inside.shtml Asthenosphere – plastic like layer below the lithosphere. The ridged plates of the lithosphere float on the more plastic layer called the asthenosphere.
Deformation – The breaking, tilting, and folding of crustal rock due to crustal movement. (three types of forces) 1.Compression – squeezing of earths crust that compacts the rock. Convergent boundary 2. Tension – is the pulling apart of the earths crust. Divergent boundary. 3. Shearing – pushes rocks side by side in opposite directions. Transform boundary.