US EPA

3727542 

Journal Article 

Manganocummingtonite from the mesoproterozoic, Sausar fold belt, central India 

Kanungo, DR; Malpe, DB; Leake, BE 

2014 

Yes 

Journal of the Geological Society of India
ISSN: 0016-7622
EISSN: 0974-6889 

SPRINGER INDIA 

NEW DELHI 

83 

1 

93-99 

English 

10.1007/s12594-014-0011-8 

WOS:000330977200011 

http:///www.springerlink.com/
Exit
 

Manganocummingtonite occurs with spessartine, quartz and pyrolusite in the Chikmara area, Sausar fold belt, central India. Its composition is [Ca0.3-0.35(Mg3.3-3.5Mn1.6-1.8Fe1.4-1.52+)(Si7.931-7.997Al0.003-0.069iv)O-22(OH1.5-2.0F0.0-0.5)] being fairly rich in Ca, which is indicative of metamorphic temperature in the amphibolite facies. The garnet contains 77.5% spessartine, 13% almandine and minor andradite, grossular and pyrope components. Unusually, there is no carbonate, pyroxene, pyroxmangite, rhodonite, magnetite or hematite. The available Al in the rock stabilized garnet and this mineral incorporated minor Fe3+ present in the rock as andradite component. The manganocummingtonite-garnet pairs developed at similar to 600 degrees C during amphibolite facies metamorphism in low X-CO2 system, stabilized with XMn/(Mn+Fe2+Mg)= 0.25 to 0.28 in the amphibole and 0.85 in the garnet and formed under unusually low fO(2) conditions for the Sausar region, near channelized fluids which deposited quartz may have controlled the fO(2). 

Manganocummingtonite; Spessartine; Oxygen fugacity; Sausar fold belt; Central India