The DeKalb area of northern New York lies within the northwest Adirondack Lowlands, part of the southern extension of the Grenville province into New York State (Fig. 1.) Metamorphism of this area occurred during the Grenville orogeny, 1.1 to 0.9 b.y. ago (Wynne-Edwards, 1972) and has been assigned to the middle to upper amphibolite facies (Wynne-Edwards, 1972). This paper presents the results of detailed mapping of the metamorphic rocks, especially the marbles, and the accompanying analytic program. A model for the metamorphic history of the area is also presented.
The field area is small (5 km2) by complex, and detailed mapping provided a basis for subdividing some of the great blue expanses of marble seen on the New York State geological map. I hesitate to extend the results of this study to a regional scale without further mapping or reconnaissance work because the innate complexity and variability of the marbles make regional extrapolation tenuous.