Alabama Tin Belt. Metallogenesis and mineral resource evaluation. Final report for the 1983-1984 project year
The Alabama Tin Belt covers an area of approximately 180 km/sup 2/ within the Tallapoosa lithotectonic block of the Northern Alabama Piedmont. In the second year of this three year project, efforts continued towards detailing the distribution and petrogenesis of tin-bearing peraluminous granitoids in central Coosa County. In particular, mapping, structural analysis and petrographical/petrological studies have been used to examine the geologic settings, geochemical and mineralogical variations, crystallization conditions and nature of source rock(s) of selected granitic plutons and related pegmatite bodies in the vicinity of Rockford, Alabama. Thermobarometeric techniques (a ternary feldspar thermobarometer and a plagioclase-muscovite geothermometer), that could be used in conjunction with compositions of constituent minerals to yield reasonable estmates of granite crystallization and alteration temperatures, were also developed. Preliminary results provide evidence that: (1) the granitoids possess characteristics possibly derived from both sedimentary (S-type) and igneous (I-type) sources; (2) feldspars of the tin-bearing pegmatites possess extremely high Rb and Cs concentrations; (3) the peraluminous granitoids crystallized under varying oxygen fugacity conditions at temperatures of 510 to 710/sup 0/ and pressures greater than 6 kbar; and, (4) the Rockford Pluton occupies the core of a post-D/sub 1/, antiformal structure that is overturned to the northwest.
- Research Organization:
- Alabama Univ., University (USA). Dept. of Geology; Murray State Univ., KY (USA)
- OSTI ID:
- 5734881
- Report Number(s):
- NP-6901446; ON: TI86901446
- Country of Publication:
- United States
- Language:
- English
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