Explaining a Non-chondritic Silicate Earth
Table 2.6 (Rollinson, 2007, p. 67) summarizes the differences between the composition of the silicate Earth and chondrites. For each group of elements, the table indicates whether the elements are depleted or enriched (relative to chondrites) in the silicate Earth and briefly indicates the fractionation process that caused the difference.
Your task in this assignment is to expand on the fractionation process in each case. For example, you will explain what might have happened during planetary accretion to cause the Earth to be depleted in light gases. Describe any supporting evidence.
As a general guideline, your answer for each element group should be one to three paragraphs long. If the mechanism for fractionation is very similar for some element groups, you may discuss them together, but be sure to address any differences in the degree of depletion or enrichment.
Compose your answers in your own words. Avoid quoting long passages from your readings. Any quotations should be cited and accompanied by explanations in your own words.
You should be able to find all of the information you need in Chapter 2 of Rollinson (2007), but if you use additional sources, cite them and list them at the end of your assignment.
Total: 30 points
