Tourmalinization of Bt-Bearing Metasedimentary Rocks, Zanskar, NW India

 

Between Darcha and Lakhang there is an extensive body of Bt-bearing metasedimentary rocks, comprising pelites, psammites and quartzites. In two places we have found extensive blocks recording the process of tourmalinization, where Tml is associated with quartz and sulfides.

 

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a) Massive tourmaline surrounding a quartz vein into biotite-rich psammite.	b) Same as (a) but notice the fracturing pattern of the tour.
c) Tourmalinization front.	d) Same. Notice the ferruginours alteration surrounding the alteration front interpreted to indicate the presence of sulfides.
e) Tourmalinization front along cracks. Note triangular shape indicative of diffusion from the crack into surrounding rocks.	f) Same.