Metamorphism may also be associated with metasomatism, and it is particularly common for arsenic to react with pre-existing sulfides, producing nickeline, gersdorffite and other Ni-Co arsenides.
42.
FGS ( 1 July 1899 10 October 1985 ) was a British geologist, best known for her work on metasomatism in rocks and her role in the " Granite Controversy ".
43.
Study of metallic ore deposits involves the use of structural geology, geochemistry, the study of metamorphism and its processes, as well as understanding metasomatism and other processes related to ore genesis.
44.
Yet Lorence G . Collins does not agree with the assumption of the K-feldspar being primary magmatic and the myrmekite being formed due to deformation-induced Na-Ca-metasomatism.
45.
IOCG deposits tend to accumulate within iron-rich rocks such as banded iron formations, iron schists, etcetera, although iron enrichment of siliciclastic rocks by metasomatism is also recognised within some areas.
46.
The alteration of the plagioclase feldspars to albite in these rocks has previously been explained as a result of metasomatism at the time of formation, and the rocks have been referred to as spilites.
47.
This mechanism implies that metasomatism is open system behaviour, which is different from classical metamorphism which is the in-situ mineralogical change of a rock without appreciable change in the chemistry of the rock.
48.
Further, because metasomatism is a mass transfer process, it is not restricted to the rocks which are changed by addition of chemical elements and minerals or hydrous crust into thin, often highly metasomatised and altered shear zones and lodes.
49.
An interesting observation concerns the fierce opposition Collins encountered amongst mainstream petrologists although there is no doubt, that metasomatic processes can be very effective as is for instance clearly demonstrated in fenites ( K-Na-metasomatism ) or in skarns.
50.
Here, metasomatism enriches a syenite massif with potassium when it comes into contact with a limestone at around 200 250 �C . This metamorphic process produces a potassium feldspar metasomatite, the typical geological environment for canasite and, therefore, frankamenite.
