Posted by dog-upb on April 13, 2009 at 9:49 AM
01 The dynamic and evolving earth (PDF format, 1 Mb)
02 Minerals and Rocks (PDF format, 3.56 Mb)
- Earth is a complex, dynamic planet that has continually evolved since its origin some 4.6 billion years ago.
- To help understand Earth?s complexity and history, it can be viewed as an integrated system of interconnected components that interact and affect each other in various ways.
- Theories are based on the scientific method and can be tested by observation or experiment.
- The universe is thought to have originated about 15 billion years ago with a Big Bang, and the solar system and planets evolved from a turbulent, rotating cloud of material surrounding the embryonic Sun.
- Earth consists of three concentric layers -- core, mantle, and crust -- and this orderly division resulted during Earth's early history.
- Plate tectonics is the unifying theory of geology.
- An appreciation of geologic time and the principle of uniformitarianism is central to understanding the evolutionary history of Earth and its biota.
- Geology is an integral part of our lives.
03 Plate tectonics: a unifying theory (PDF format, 7.4 Mb)
- Chemical elements are composed of atoms, all of the same kind, whereas compounds form when different atoms bond together. Most minerals are compounds, which are characterized as naturally occurring, inorganic, crystalline solids.
- Of the 3500 or so minerals known, only a few, perhaps two dozen, are common in rocks, but many others are found in small quantities in rocks and some are important natural resources.
- Cooling and crystallization of magma or lava and the consolidation of pyroclastic materials account for the origin of igneous rocks.
- Geologists use mineral content (composition) and textures to classify plutonic rocks (intrusive igneous rocks) and volcanic rocks (extrusive igneous rocks).
- Mechanical and chemical weathering of rocks yields sediment that is transported, deposited, and then lithified to form detrital and chemical sedimentary rocks.
- Texture and composition are the criteria geologists use to classify sedimentary rocks.
- Any type of rock may be altered by heat, pressure, fluids or any combination of these, to form metamorphic rocks.
- One feature used to classify metamorphic rocks is foliation -- that is, a platy or layered aspect, but some lack this feature and are said to be nonfoliated.
- The fact that Earth materials are continually recycled and that the three families of rocks are interrelated is summarized in the rock cycle.
04 Geologic time: concepts and principles (PDF format, 3.2 Mb)
- Plate tectonics is the unifying theory of geology and has revolutionized geology.
- The hypothesis of continental drift was based on considerable geologic, paleontologic, and climatologic evidence.
- The hypothesis of seafloor spreading accounts for continental movement and the idea that thermal convection cells provide a mechanism for plate movement.
- The three types of plate boundaries are divergent, convergent, and transform. Along these boundaries new plates are formed, consumed, or slide past one another.
- Interaction along plate boundaries accounts for most of Earth's earthquake and volcanic activity.
- The concept of geologic time and its measurements have changed throughout human history.
- The principle of uniformitarianism is fundamental to geology.
- Relative dating -- placing geologic events in a sequential order -- provides a means to interpret geologic history.
- The three types of unconformities -- disconformities, angular unconformities, and nonconformities -- are erosional surfaces separating younger from older rocks and represent significant intervals of geologic time for which we have no record at a particular location.
- Time equivalency of rock units can be demonstrated by various correlation techniques.
- Absolute dating methods are used to date geologic events in terms of years before present.