Contact
Jochen Kolb
Mail:
jkol@geus.dk
Phone: 3814 2212
Troels F.D. Nielsen
Mail:
tfn@geus.dk
Phone: 3814 2224
|
Petrological and geochemical studies help to unravel the geological history of regions, rock formations, and mineral deposits. Together with
geological mapping
they form the basis for evaluation of economic potentials.
We use
microscopy
of rocks and mineral textures,
rock geochemistry,
mineral geochemistry, isotope chemistry, fluid inclusion studies,
age dating, and modelling in the studies.
Metamorphic rocks
Greenland is dominated by metamorphic rocks formed during plate tectonic cycles of rifting, collision, mountain building, denudation, and metamorphism. Petrological, geochemical and age studies are used for understanding:
-
Regional metamorphic regimes during assemblage of continents
-
Regional and local geochemical regimes related to mineralisation events
-
The history and age of the continental areas
Mineral deposits
Petrological and geochemical studies of geological environments and processes of mineral deposits are made for development of exploration models. The aim is to understand, e.g.:
-
Regional lithological, textural and geochemical environments of mineralisation events
-
Critical parameters for the development of mineral deposits
-
Parageneses of mineralisation for evaluation of potentials and processing
Igneous rocks
Igneous rocks are related to continental break-up, continental rifting, and collision of land masses. The petrology and geochemistry of igneous rocks reflect the dynamic environment and give indications for the economic potential of individual occurrences as well as larger igneous provinces both onshore and offshore. The studies include:
-
Volcanics of the Tertairy North Atlantic Igneous Province: description of geological history, environments, mantle melting processes, and melt fractionation processes
-
Fundamental principles of magma evolution and crystallisation in magma chambers
-
Description and evaluation of ore deposits in igneous complexes
-
Origin of continental carbonate-rich magmatism in central complexes and kimberlitic provinces
|
Palladium (Pd), gold (Au) and copper (Cu) in drill core
90-22 from the platinum group element and gold
deposit in the Middle zone of the Skaergaard
intrusion. The perfectly concordant levels of Pd
concentration are found throughout the intrusion
(T.F.D. Nielsen). (
See large figure)
Eclogite nodule in the Majuagaa kimberlite
dyke, Maniitsoq region, West Greenland.
Metamorphic reaction texture involving an ultramafic rock (orange material in background). As a result of the reaction, the mineral gedrite (bluish, crossed pattern) has grown at the expense of the original material. Overgrowths of symplectitic (radiating) structures including kornerupine and plagioclase partially obscure the gedrite minerals.
|
