Steven R. Bohlen

U-Pb Garnet, Sphene, Monazite, and Rutile Ages: Implications for the Duration of High-Grade Metamorphism and Cooling Histories, Adirondack Mts., New York

U-Pb ages were determined on metamorphic garnets, monazites, sphenes, and rutiles in metapelites and marbles from the Adirondacks to determine the duration of metamorphism, the timing of mineral growth, and the cooling history. Garnet ages for the Lowlands range from 1168-1127 Ma, those from the central and southern Highlands from 1154-1013 Ma. The ages indicate that metamorphism may have begun synchronously throughout the Adirondacks, but high-grade conditions existed over a period of about 150 Ma in the Highlands and only about 40 Ma in the Lowlands. Metamorphism in the Highlands may not have occurred as a single event but rather in several discrete thermal pulses. An age of

Stability of hydrous phases in subducting oceanic crust

1153 pm 3 Ma

Kinetics of the coesite to quartz transformation

was determined for garnets in the syn-regional metamorphic contact aureole of the Diana syenite, consistent with that of the syenite intrusion,

The Reaction Titanite+Kyanite=Anorthite+Rutile and Titanite-Rutile Barometry in Eclogites

1155 pm 4 Ma

Time and metamorphic petrology: Calcite to aragonite experiments

(U-Pb zircon, Grant et al. 1986). Garnets just outside the contact aureole give an age of