Talc Thin Section

Modal proportions correlate well with the ones observed in thin section.

Talc thin section. Talc has the chemical formula mg 3 si 4 o 10 oh 2 it is probably best know for its low hardness although it has a micaceous structure it is so easily deformed that crystals are rarely seen. In thin section talc is colorless biaxial negative with a 2v of 0 to 30 o. At 78 6 mbsf this rock is pervasively altered with amphibole quartz chlorite oxides and sulfides making up a significant fraction of the rock along with serpentine and varying proportions of talc cf.

Talc carbonate rocks formed by the breakdown of the serpentine in the previously formed serpentinite rock at temperatures 550 c and elevated x co2. Thin section of massive fine grained talc replacing coarse dolomite in crossed polarized light. The abundance of amphibole in the mylonite.

Get geology toolkit premium for more features of sericite thin section under the microscope. There you ll find additional information on this and many. Talc mg 3 si 4 o 10 oh 2 allegedly named in 1546 by georgius agricola georg bauer from arabic talq pure probably alluding to the color of its powder.

A zussman j. An introduction to the rock forming minerals pp. Biotite is a solid solution between the end members phlogopite kmg 3 alsi 3 o 10 oh 2 and annite kfe 3 alsi 3 o 10 oh 2 although pure annite does not occur in nature in addition small amounts of na rb cs and ba may substitute for k and like in other minerals f can.

Thin section description of sample 209 1268a 15r 1 75 77 cm. Muscovite has a higher birefringence and higher 2v properties which easily distinguish the 2 minerals. Mineralogical society of great britain and ireland london.

This sample is from the sweetwater view mine ruby range sw montana. The talc close to the dolomite tends to be more fine grained. Talc thin section.