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The formation of lead carboxylates (lead soaps) has been identified as the cause of deterioration of hundreds of oil paintings. Soaps form when heavy metal-containing pigments, for example lead white and lead-tin yellow, react with saturated fatty acids in the oil medium. Understanding the mechanism of the reactions requires chemical information, which can be obtained with solid-state ²⁰⁷Pb, ¹¹⁹Sn and ¹³C NMR spectroscopy. Using the chemical-shift tensors determined by solid-state NMR we can gain structural insights on the coordination environment of the lead carboxylates and identify and quantify components in a paint film mixture. We have examined the spectroscopy of lead-containing pigments, lead carboxylates, and model paint films that were subjected to accelerated aging. We have also begun to investigate the dynamics of soap formation by ¹³C NMR spectroscopy. The NMR methods applied to the model paint systems could also be applied to other lead-containing materials. 

Magmatism in the southern Grenville Province records a collisional and postcollisional history during the period 1.20–1.15 Ga in the Adirondack Lowlands (New York State, USA) and the Frontenac terrane (Ontario, Canada). The 1.20 Ga bimodal Antwerp-Rossie suite of the Adirondack Lowlands was produced by subduction in the Trans-Adirondack backarc basin. This was followed by intrusion of the 1.18 Ga alkalic to calc-alkalic Hermon granite, which may have been generated by melting of metasomatized mantle during collision of the Adirondack Lowlands and Frontenac terrane during the Shawinigan orogeny. The Hyde School gneiss plutons intruded the Adirondack Lowlands at 1.17 Ga, and Rockport granite intruded into the Adirondack Lowlands and Frontenac terrane, stitching the Black Lake shear zone, which marks the boundary between these terranes. Subsequent extensional collapse and lithospheric delamination caused voluminous anorthosite-mangerite-charnockite-granite plutonism. In the Frontenac terrane, this event is represented by the 1.18–1.15 Ga Frontenac suite, which is composed predominately of ferroan granitoids produced from melting of the lower crust by underplating mafic magmas. The Edwardsville, Honey Hill, and Beaver Creek plutons are newly recognized members of this suite in the Adirondack Lowlands. High oxygen isotope ratios of this suite in the central Frontenac terrane and western Adirondack Lowlands point to the presence of underthrust altered oceanic rocks in the lower crust. Oxygen isotopes of the Frontenac suite in both terranes preclude its derivation from mantle melts alone.