Odinite is an iron silicate clay mineral which is forming today in tropical shallow-marine environments with river input and reducing conditions (“The Verdine facies”). There are several lines of evidence that it may be a precursor for chlorite coatings in sandstones, which again help sandstones to remain porous at greater burial.
In the special tropical shallow marine environment, the sediment supply from rivers together with marine biota, provide the elements and the right reducing condition in forming odenite. Odenite contains both ferrous and ferric iron, magnesium, aluminum, and silica, with the general formula:
(Fe(III), Fe(II), Mg, Al)2(Al,Si)O5(OH)4
Odinite is known to form under so-called post-oxic conditions found in sediments close to the ocean-sediment boundary.
Odenite has previously been produced as a byproduct in experiments to study how smectite surroundings of iron cannister with nuclear waste behave. To our knowledge, the controlled synthesis of odinite from natural materials representative of tropical shallow-marine environments has not been systematically investigated.
The suggested laboratory experiments will use natural geological materials together with model seawater. It is important to control the redox conditions in a glove box or similar. Two types of experiments are envisaged: one initial series run at higher temperature, and a second series run at room temperature for longer times.
Aims: The aim of this study is to use laboratory experiments to synthesize odinite from material that mimic natural analogues.
Requirements: Basic knowledge of chemistry,
Students who want to work with this thesis is required to take GEO5900 – Chemical processes in soil and groundwater.
Learning outcome: Knowledge and experience related to geochemical modelling and mineral synthesis relevant for environmental geosciences and sedimentology.