Marijuana on Federal Lands. Posted: January 27, 2014. With the legalization of marijuana in the State of Colorado, Mesa Verde National Park would like to provide clarification regarding the use of possession of marijuana on Federal lands.
Plate Tectonics. Plate tectonics is the movement of the Earth's crust through convection currents that occur in the mantle. Divergent plate boundaries occur where hot magma rises to the surface, pushing the plates apart. The mid-ocean ridges form at divergent plate boundaries.
Tectonic plates are segments of the Earth's lithosphere, the hard rocky outer shell composed of the crust and the uppermost mantle. This shell is divided by lines of faults, ridges of plate creation, and zones of plate destruction. The plates are composed of crustal rock and solid upper mantle which is called the lithosphere. * 2  Plates are composed of continental and oceanic crust. 3  The oceanic crusts are continually moving, spreading from the center, sinking at the edges, in a process of recycling.