This program examines the traces left by early plants, animals, and single-celled organisms and follows the progression of life forms over time.
Connections are drawn between atmospheric gases, climate change, rock formation, biological functions, and mass extinctions. Minerals: The Materials of Earth Minerals have been indispensable to human civilization.
Images of an actual landslide illustrate the phenomenon. Sedimentary Rocks: The Key to Past Environments This program returns to the Grand Canyon: its exposed layers of sedimentary rock allow scientists to peer into the geologic past. Metamorphic Rocks The weight of a mountain creates enough pressure to recrystallize rock, thus creating metamorphic rocks.
The movement of sediment and its deposition are covered, and the processes of lithification, compaction, and cementation that produce sedimentary rocks are explained. This program outlines the recrystallization process and the types of rock it can create from claystone and slate to schist and garnet-bearing gneiss.
The program covers convergent boundaries, subduction, hotspots, and the debate over what drives plate motion. Mountain Building This program erodes the myth of the mountain as a solid, permanent structure.
Animations are used to illustrate the process of orogeny (mountain building) through accretion and erosion, as well as the role of plate tectonics, the rock cycle, and how different types of rock are formed in the course of mountain building. Earth's Structures A visit to the Grand Canyon lays the foundation for this exploration of rock layers and deformation.
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The program also surveys the various types of eruptions, craters, cones and vents, lava domes, magma, and volcanic rock. Experts provide a graphic illustration of this process and explain the types and textures of rocks such as granite, obsidian, and quartz.This series shows the physical processes and human activities that shape our planet.From earthquakes and volcanoes to the creation of sea-floor crusts and shifting river courses, Earth Revealed offers stunning visuals that explain plate tectonics and other geologic concepts and principles.Geophysicists use seismic wave studies, variations in temperature, magnetic fields, gravity, and computer simulations to create models of deep structures. The Sea Floor The mysteries of the ocean floor lie hidden under enormous pressure and total darkness.This program looks at the research submersibles and indirect methods used to study the bottom of the sea, providing a glimpse of volcanic activity, formations such as the continental shelf and mid-ocean ridges, and life forms that thrive at extreme depths. The Birth of a Theory In the 1960s, earth scientists developed the theory of plate tectonics.