16-41 Analysis of Titanite from the Oak Hill Wollastonite Deposit, Eastern Adirondacks

Session: From Thin Section to Outcrop: Exploration of Undergraduate Research (Posters)

Presenting Author:

Authors:

Abstract:

Wollastonite skarn deposits in the eastern Adirondacks record multiple thermal events during the Grenville orogeny. Wollastonite is a valuable industrial mineral with a notable acicular crystal habit that is used as a versatile, functional filler and reinforcing agent in plastics, paints, and ceramics. In this study, we attempt to characterize the thermal history of the Oak Hill wollastonite deposit (Lewis, NY) using titanite. Samples were collected from the pit and analyzed at the Arizona LaserChron Center for U-Pb dating and LA-ICPMS titanite mineral chemistry. Thirty-five spots were analyzed. Additional samples from drill core were examined petrographically.

Previous work on these deposits using zircon (e.g., Peck et al. 2025, J. Petrol. 66:4) showed distinct age populations corresponding to known thermal events in Adirondack geological history, i.e., Shawinigan, AMCG, Ottowan, and Rigolet. Our titanite ages show either heterogeneous Pb incorporation or, perhaps more likely, Pb-loss. A Tera-Wasserburg plots yields a weighted mean age of 948.9 +/-3.7 Ma, which is best viewed as a minimum rather than a true formation age. The titanites appear homogeneous across samples: titanite grains show no zonation in electron backscatter imaging or within the laser ablation data. On a chondrite-normalized REE plot they all show distinct negative Nd-anomalies and negative Eu-anomalies, the latter presumably due to the ircrystallization in the presence of abundant plagioclase.

© Copyright 2025 The Geological Society of America (GSA), all rights reserved.