Abstract
This chapter catalogues some of the secular changes in basaltic volcanic rocks, the tectonic settings in which they might have formed in comparison to the compositions of modern basaltic rocks from different environments and the implications for their source mantle compositions. Precambrian basalts of various ages from greenstone assemblages are compared geochemically to evaluate more fully their reliability in monitoring mantle evolution, and to see if they record significant petrogenetic changes across the Archaean-Proterozoic boundary. Results indicate that greenstone assemblage basalts probably sample only a very small proportion of the mantle at any given time, and that they should not be used to record changes in the composition of large volumes of the mantle. The compositional differences between late Archaean and early Proterozoic basalts appear to reflect the rapid growth of the continents towards the end of the Archaean. -from Author
| Original language | English |
|---|---|
| Pages (from-to) | 40-55 |
| Number of pages | 16 |
| Journal | American Society of Mechanical Engineers (Paper) |
| Publication status | Published - 1990 |