Research – Petrology

Projects in the petrology group fall into the following general themes:

  • Melting processes in mantle-rocks, particularly source rocks consisting of mixed rock types such as pyroxenites and mica-bearing rocks in addition to peridotite.
  • Crystallization processes in magmas interpreted by studies of volcanic rocks.
  • The patterns and causes of trace element distribution in igneous and metamorphic rocks.
  • Origin and characteristics of alkaline igneous rocks
  • Distribution and of volatile components such as C, H, O, S, N and P in rocks and their effects on melting and crystallization.
  • Geodynamic processes during the first half of Earth history and differences to modern geological processes.

Examples of current projects are:

  1. The trace element composition of olivine occurring as phenocrysts in igneous rocks is compared to olivines in mantle rocks to understand recycling of oceanic and continental crust into the mantle and its involvement in melting processes. This work emphasizes the Mediterranean area.
  2. The time at which plate tectonics began to operate on the Earth is debated, with most opinions favouring sometime between 4,200 and 3,000 million years ago. We are studying Archaean rocks and also forward modelling of possible pre-plate processes to understand early plate tectonics and how the Earth might have worked before plate tectonics.
  3. Our studies of the petrology and mineral chemistry of mantle rocks is currently focused on mica- and pyroxene-rich rocks from Africa, particularly the Tanzanian craton and the Cameroon line.