Northeastern Section (39th Annual) and Southeastern Section (53rd Annual) Joint Meeting (March 2527, 2004)
Paper No. 69-5
Presentation Time: 8:00 AM-12:00 PM

DISTRIBUTION OF L- AND L-S TECTONITE IN THE OLIVER HILL DOME, EASTERN ADIRONDACK MOUNTAINS, NEW YORK

SMITH, Nathan1, VALENTINO, David W.1, CHIARENZELLI, Jeffrey R.2, and SOLAR, Gary S.3, (1) Department of Earth Sciences, State Univ of New York at Oswego, Oswego, NY 13126, natex@twcny.rr.com, (2) Department of Geology, State Univ of New York at Potsdam, Potsdam, NY 13676, (3) Department of Earth Sciences, SUNY College at Buffalo, 1300 Elmwood Avenue, Buffalo, NY 14222

The Adirondack mountains of NY State are underlain by Proterozoic rocks that are cross-cut by numerous large ductile shear zones. These shear zones contain a wide range of fabrics including L-, L-S and S-tectonites. Although these fabrics have been described by earlier workers, the distribution of intensity variation within specific ductile shear zones has only been documented locally. During this study we examined, in detail, the distribution of these fabrics within a shallowly dipping ductile shear zone that occurs in the area north of Olmsteadville, NY, at Oliver Hill and Green Mountain. Penetrative foliation occurs in granitic- and charnockitic-gneiss. This foliation is defined by planar aggregates of quartz and feldspars, with accessory biotite, hornblende, and occasional clinopyroxene. The foliation defines a broad open dome, but at the scale of kilometers, the foliation is highly variable in attitude. Although mineral lineations occur in all rocks of this region, they are best developed on the southern flank of the Oliver Hill dome, where a 1.5 km wide zone of L>>S tectonite occurs. Lineations are defined by rod-shaped aggregates of dynamically recrystallized quartz and feldspars, and accessory mafic phases. The lineations have a trend that ranges from 080 to 125, with the maximum trend at 110. The plunge is generally shallow, with an average of 09 eastward. The meta-igneous rocks occur structurally above a sequence of deformed meta-sedimentary rocks including marble, phlogopite-schist, pelitic- and psammitic-gneiss, all interlayered at the scale of meters to 10s of meters. Kinematic analysis was performed on rocks containing L-S fabrics. Type I S-C, sigma- and delta-porphyroclasts, and shear bands were all observed, and the shear sense is consistently top toward the west. These data suggest that the meta-igneous rocks were thrust westward over the meta-sedimentary rocks in this part of the Adirondacks.

Northeastern Section (39th Annual) and Southeastern Section (53rd Annual) Joint Meeting (March 2527, 2004)
General Information for this Meeting
Session No. 69--Booth# 9
Structural Geology (Posters)
Hilton McLean Tysons Corner: Ballrooms A and B
8:00 AM-12:00 PM, Saturday, March 27, 2004

Geological Society of America Abstracts with Programs, Vol. 36, No. 2, p. 138

© Copyright 2004 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.