The P-T-t history of a Barrovian sequence in Dutchess County, New York, and the adjacent part of Connecticut

The P-T-t history of a Barrovian sequence in Dutchess County, New York and the adjacent part of Connecticut was studied. Using the average P-T mode in THERMOCALC, the following P-T results were calculated for the garnet, staurolite, kyanite and sillimanite-K-feldspar zones (1sigma uncertainties): 5.2+/-0.8 kbar, 570+/-12°C 5.9+/-1.1 kbar, 557+/-12°C 6.4+/-1.1 kbar, 600+/-29°C and 7.4+/-1.4 kbar, 752+/-68°C, respectively. Phase equilibria modeling in the MnNCKFMASHTO system yields peak P-T results consistent with the average P-T results.Monazite ages were obtained for the garnet, staurolite, kyanite and sillimanite-K-feldspar zones (2sigma uncertainties): 455+/-6 and 453+/-10 Ma 451+/-9 and 438+/-8 Ma 478+/-6, 431+/-4 and 425+/-8 Ma 533+/-7 Ma, 507+/-6, 506+/-4 Ma and 472+/-5 Ma, respectively. These ages help to constrain the timing of the Taconic and Salinic orogenic events.