COMPARISON OF CALCITE PLUS DOLOMITE THERMOMETRY AND CARBONATE PLUS SILICATE EQUILIBRIA - CONSTRAINTS ON THE CONDITIONS OF METAMORPHISM OF THE LLANO UPLIFT, CENTRAL TEXAS, USA | Academic Article individual record
abstract

Temperatures based on the composition of calcite coexisting with dolomite range from 475 to 600C for 63 marbles from the Llano uplift of central Texas. In some cases, high temperatures were determined for marbles that contain an isobarically invariant assemblage consisting of calcite + dolomite + tremolite + diopside + forsterite. In contrast, relatively low calcite + dolomite temperatures of 475-480C were obtained for marbles containing the assemblage calcite + dolomite + tremolite + talc. Agreement between the calcite + dolomite temperatures and those inferred from silicate + carbonate equilibria in the marbles indicates that the temperatures generally reflect peak conditions of metamorphism, although some resetting has occurred. The marbles having the highest calcite-dolomite temperatures are generally found close to post-tectonic pluton contacts. Relatively low temperatures are recorded within approximately 2 km of pluton contacts, suggesting a possible thermal aureole. However, relatively high temperatures of 550-600C are recorded in marbles that are not spatially related to post-tectonic granites. These temperatures may be relicts of an earlier metamorphic event. -from Authors

authors
publication outlet

AMERICAN MINERALOGIST

author list (cited authors)
LETARGO, C., LAMB, W. M., & PARK, J. S.
publication date
1995
identifier
107843SE
Digital Object Identifier (DOI)
start page
131
end page
143
volume
80
issue
1-2