US EPA

6867804 

Journal Article 

Ca-Fe-Si SKARNS CONTAINING BABINGTONITE: FIRST KNOWN OCCURRENCE IN AUSTRALIA 

Gole, MJ; , 

1981 

Yes 

Canadian Mineralogist
ISSN: 0008-4476
EISSN: 1499-1276 

MINERALOGICAL ASSOC CANADA 

QUEBEC 

269-277 

WOS:000208512800005 

At Black Perry Mountain. southern New South Wales, skarns containing hedenbergite (Hed), andradite (And), ilvaite, quartz (Qtz). calcite (Cal), magnetite, actinolite. epidote, babingtonite and stilpnomelane extend for 4 km away from an exposed granite contact. All skarn outcrops contain similar rnineral assemblages except for babingtonite assemblages. The main minerals have nearlv pure Ca-Fe end-member compositions and have similar compositions throughout the skarns. This is the first occurrence of babingstonite in Australia. Its formula is Na0.04Ca2.00Fe0.762+Mn0.15Mg0.12Fe0.993+,Al0.04SL4.96 O-14(OH)(0.96); its cell data are a 7.49(1)., 11.83(1), c 6.72(1) angstrom. alpha 95.3(1)degrees, beta 92.3(1)degrees and gamma 103.1 (1)degrees, and its optical properties are n(alpha) 1.716(2), n(beta) 1.731(2), n(gamma) 1.750(2), Z Lambda c 43(3)degrees and 2V (alpha) 69 (3)degrees. The first-ormed assemblase (Hed-And-Qtz-Cal) occurs in all skarn outcrops. which suggests that these skarns experienced similar peak metamorphic conditions. Thus the sranite would be buried not too deeply below the skarns. Assemblages containing ilvaite. babingtonite. actinolite and stilpnomelane developed after the formation of Hed-And- Qtz-Cal. Experimental data indicate that Hed-And-Qtz-Cal formed between about 580 and 640 degrees C, with f(O-2). just above the upper f(O-2) stability of graphite and X(CO2) between similar to 0.1 and similar to 0.3.