The role of fluids in the formation of talc deposits of Rema area, Kumaun Lesser Himalaya

Talc deposits of Rema area in the Kumaun Inner Lesser Himalaya are hosted within high magnesium carbonates of the Proterozoic Deoban Formation. These deposits occur as irregular patches or pockets mainly within magnesite bodies, along with impurities of magnesite, dolomite and clinochlore. Textures...

Full description

Saved in:
Bibliographic Details
Published in:Journal of the Geological Society of India 2009-02, Vol.73 (2), p.237-248
Main Authors: Sharma, Rajesh, Joshi, Prabha, Pant, P. D.
Format: Article
Language:English
Subjects:
Calcium chloride
Carbon dioxide
Carbonates
Diagenesis
Dolomite
Earth and Environmental Science
Earth Sciences
Fluid dynamics
Geochemistry
Geology
Hydrogeology
Magnesium
Mineralogy
Petrography
Quartz
Silica
Sodium chloride
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Talc deposits of Rema area in the Kumaun Inner Lesser Himalaya are hosted within high magnesium carbonates of the Proterozoic Deoban Formation. These deposits occur as irregular patches or pockets mainly within magnesite bodies, along with impurities of magnesite, dolomite and clinochlore. Textures represent different phases of reactions between magnesite and silica to produce talc. Petrography, XRD and geochemistry reveal that the talc has primarily developed at the expense of magnesite and silica, leaving dolomite largely un-reacted. Early fluid inclusions in magnesite and dolomite associated with talc are filled with H 2 O+NaCl+KCl ± MgCl 2 ± CaCl 2 fluids, which represent basin fluid system during diagenesis of carbonates. Their varied degree of re-equilibration was although not pervasive but points to increased burial, and hence requires careful interpretation. H 2 O-CO 2 fluid with XCO 2 between 0.06 and 0.12 was equilibrated with talc formation. The reaction dolomite+quartz → talc was not extensive because T-X CO2 was not favourable, and talc was developed principally after magnesite+quartz.
ISSN:0016-7622
0974-6889
DOI:10.1007/s12594-009-0080-2