Certainly! Here's an explanation of the image illustrating the carbonate system precipitation process:
Geological Context: The image shows a cross-section between Ika Fjord and Arsuk Fjord, with Gronnedal in between. This area is noted for the presence of carbonate minerals and rare earth elements (REE).
Enriched REE Zone: The red-orange zone represents an area enriched with REE and possibly other elements like Nb and Ta (niobium and tantalum). This zone is located above a layer of carbonate.
Carbonatite: Carbonatite is a type of igneous rock rich in carbonate minerals. In the image, it's depicted as a layer beneath the enriched REE zone.
Weathering and Leaching: The process starts with the weathering of the material at the top, which leads to the leaching of CaCO3 (calcium carbonate) from the carbonatite. This leaching occurs due to water movement influenced by the water table, which is shown in blue.
Path of Carbonate: The path of carbonate dissolution is indicated by arrows moving from the carbonatite layer downwards into the water table. This process involves the dissolution of carbonate minerals, which carries away some of the CaCO3, leaving behind concentrated REE.
Water Table: The water table is where the groundwater level is located, and it plays a crucial role in the leaching process. The water here has a varying pH, which aids in dissolving carbonate minerals.
Concentration of REE: As CaCO3 is leached out, the remaining REE become more concentrated in the enriched zone. This is because the carbonate minerals that previously held these elements are now dissolving, leaving the REE behind.
Geophysical Evidence: The text notes that geophysical evidence suggests the mineralization (concentration of minerals) is deeply seated, meaning the process has been occurring over a long geological time frame and at significant depths.
Trench/Hill Samples: The image mentions trench/hill samples, which are likely locations where samples have been taken to study the concentration and composition of the minerals.
In summary, this image illustrates how the interaction between water and carbonate minerals in the presence of REE leads to the leaching of CaCO3, thereby concentrating the REE in the subsurface zone between the fjords. This process is significant for understanding the distribution and potential extraction of rare earth elements in such geological settings.
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