Date of Award
Master of Science (MS)
The middle Ordovician rocks of the Albany 15 minute quadrangle comprise interbedded graywacke and shale, and in the east, coarse cobble or olistostromic deposits. The detrital composition, westward fining and regional westward transgression of these deposits indicate that these were sediments shed off the westward thrusting Taconic Allochthon. Primary sedimentary structures show that these rocks were deposited by turbidity currents flowing into a longitudinal trough, probably formed in response to increased load during overthrusting. Although strongly dependent on lithology, deformation intensity generally increases from west to east; from essentially undeformed bedded flysch through asymmetrically folded and thrust beds to highly deformed melange containing isoclinally folded, transposed and boudinaged beds within a phacoidally cleaved shaly matrix. Folds in the least deformed flysch are generally open and have horizontal hinge lines. In more highly deformed rocks folds are isoclinal with hinge lines plunging to the SE. This suggests that with increased strains overturned folds in the flysch rotated into the direction of maximum finite extension. This direction corresponds with the overthrust direction indicated by slickenside striations on minor fault planes. Fold development apparently occurred as a two phase progressive event, with initiation of buckle folds followed by the development of extreme noncylindrial hinge lines accompanying brittle failure and boudinage. Locally, a third phase of folding has occurred. In addition, an early phase of chaotic folding occurred within a chert and siliceous argillite unit. The formation of the Taconic melange in this area can be explained through the progressive disruption of a syndepositionally deformed turbidite fan complex, which included coarse proximal or olistostromic facies. Additionally, thrusting has led to the incorporation of slivers or klippes of older facies into the melange.
Vollmer, Frederick W., "Structural Studies of the Ordovician Flysch and Melange in Albany County, New York" (1981). Geology Theses and Dissertations. 94.
Plate 1a - Geological map of a portion of the Albany 15 minute quadrangle, New York
vollmermspl1bxs.pdf (970 kB)
Plate 1b - Schematic cross-sections, Albany 15 minute quadrangle, New York
vollmermspl2vlyck.pdf (1675 kB)
Plate 2 - Structural Map of Vly Creek, New Scotland, New York
vollmermspl3vlomank.pdf (3174 kB)
Plate 3 - Structural Map of Vloman Kill, Bethlehem, New York
vollmermspl4nskill.pdf (3806 kB)
Plate 4 - Structural Map of Normans Kill Gorge, Albany, New York (coloured outcrop map compilation by W. Kidd; combines the map in Vollmer's thesis with the map in the MS thesis of A. Plesch)
PleschNYSCDmap.pdf (583 kB)
Geological map of the New York Capital District (scale 1: 69,000)