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Byron D. Stone

Publications and source records attributed to Byron D. Stone.

51 records · Page 3Linked to original sources
USGS1976

Analysis of slump slip lines and deformation fabric in slumped Pleistocene lake beds

Slumped glacial delta sands and silts exhibit flexural slip folds and low-angle thrust faults where the beds remained coherent during slump deformation. Alternating cross-cutting relationships between f (sub l ) and f (sub r ) fold axial planes indicate that these fold groups are conjugate sets, related to the same slump movement. Analysis of slump fold axis orientations by the separation-angle method yields the fold slip plane and fold slip line. A deformation fabric reference diagram, deduced from fold and thrust fault data, shows a vertical deformation plane that is defined by the pole to the f (sub l ) and f (sub r ) fold slip planes, pole to rotated bedding, pole to thrust faults, and the fold slip lines. Central tendency estimators, Theta , Theta , and P 50 , of distributions of fold azimuths show close agreement, as do dispersion indicators sigma , derived from L values, and (P 84 -P 16 )/2. Fold axis orientations in the slumped mass are normally distributed, but the perpendiculars to deduced slip lines have consistently higher azimuth values than other central tendency values. These results may indicate that the sampling plain biased the populations. In this case, the vector mean is not perpendicular to the deduced slip line. Silt intraclast breccias, containing slump overfolds, appear to have been deposited as noncoherent grain flows in the slump depression subsequent to slump deformation. The distribution of overfold axis orientations is not significantly different from random distributions. Separation-angle analysis of the same lower breccia data yields a valid slip line solution.

New Hampshire↗
USGS1971

Deglaciation events in part of the Manchester South 7.5' quadrangle south-central New Hampshire

The study-area lies in south-central New Hampshire, and is bordered on the west by the Merrimack River, the principal north-south drainage route of central New Hampshire. The classical two tills of New England outcrop in the area. In a unique exposure of the sandy upper till, a loose ablation unit overlies a compact basal unit. Both upper till facies overlie a sheared section of dense, olive-gray lower till. Outwash sequences mapped in the study-area are progressively younger to the north, indicating backwastage of the Wisconsinan ice sheet. Primary structures in proglacial Lake Merrimack sediments include contorted bedding, buckled laminae, and folds. A large slumped section in lake sediments exhibits three distinct deformation zones, characterized by brittle, ductile, and unconsolidated deformation. Cross-cutting relationships establish four fold generations and a deformation sequence in the slumped section. Slip in each fold generation was along nearly parallel slip-lines, as deduced from analyses of fold rotation senses. The primary and slump deformation features contrast sharply with the intense style of deformation of lake beds below till at an apparent ice readvance cut. The deduced drag fold slip-line agrees with till fabric point maxima and dip-slip on one group of thrust faults. A southerly movement of readvancing ice is inferred. The study-area was deglaciated about 13,000 years ago, according to a proposed deglaciation model for New Hampshire. The model is based on Nye's theoretical glacier surface gradient, and evidence for active retreat of the Wisconsinan ice sheet.

Open-File Report↗