The overall aim of this courseware module is to explain the geochemical processes required to form the elements, incorporate them into and distribute them within the Earth, and to outline the consequences for the composition of Earth materials.
The module consists of four main sections, preceded and followed by self-assessment quizzes. The module treats the 'Basic Skills for Earth Sciences' module as a prerequisite and attempts where possible to retain the style of that module so that there is some continuity.
A series of questions about the nature of elements, isotopes, ions and their place within the Periodic Table.
Part of the explanation of the way the composition of the solar system is determined
Definitions of nuclear fusion and nuclear fission and an explanation and plot of binding energy v atomic mass. An explanation of the Big Bang and synthesis of hydrogen and helium in the protouniverse.
A summary of stellar evolution, basic nucleosynthesis reactions in normal stars up to mass 56, and temperatures needed to synthesise the different elements.
An explanation of supernovae and synthesis of the heavy elements by slow and rapid neutron capture.
A discussion of fission reactions, fission products and actinides
together with a description of the mechanism of nuclear power
generation and its similarity to natural processes.
An outline of methods for determining the pattern of element abundances within the Solar System.
The process of condensation from a nebula and the concept and classification of refractory and volatile elements.
A description of meteorite types, their relationships and the significance of carbonaceous chondrites as representing Bulk Earth material. The Chondritic Earth Model is considered and its implications for accretion of the Earth.
An interactive Solar System fact sheet gives differences between planets and explanations in terms of variations in nebula and retention of volatile elements during condensation.
A description is given of how the Earth came to be differentiated into core, mantle and crust, and how different characteristics of elements of the Periodic Table have determined the element distributions.
The Goldschmidt classification into siderophile, chalcophile, lithophile and atmophile elements is considered in relation to the early partitioning of elements within the Earth. Partition coefficients are identified as the key to understanding element distribution. Electronegativity and its relation to different types of bonding is defined and explained.
The emphasis in this section is on explaining how chemistry dictates why different elements tend to become incorporated into one or more of the main rock groups. For igneous rocks this is considered under headings that include changing magma compositions, the Rayleigh Fractionation Equation and classification. Sedimentary rocks are considered under these subheadings: composition, weathering, and the importance of ionic potential. For metamorphic rocks, immobile elements are defined and applied to the geochemical fingerprinting of altered rocks.
The use of rare earth elements in the interpretation of igneous and sedimentary rocks is also explained.
A series of questions to test your understanding of the material covered in the module.
The different parts of the module are accessed via a main menu and navigation around the module is by means of buttons along the base of the screen.
Other Modules Available
| Arc Magmatism | Aspects of Earth Resources | Basic Petrography | Basic Skills for Earth Sciences | Crystallography | Dynamic Stratigraphy: Controls and Products | Exploring the Shallow Subsurface using Geophysics | Field Safety for Geologists | Fossils as Palaeoenvironmental Indicators | Geological Map Skills | Ocean Crust and Ophiolites | Optical Mineralogy | Petrogenesis of Granitic Rocks | Phase Diagrams in Igneous Systems | Radiogenic Isotopes in Geological Sciences | Rock Deformation and Geological Structures | Systematic Palaeontology: the Phylum Mollusca | Using the Compass/Clinometer | Using Stereonets in Geology | Visualising Geology in 3D |
