Date of Award

5-2010

Document Type

Thesis

Degree Name

Master of Science (MS)

College/School

College of Science and Mathematics

Department/Program

Earth and Environmental Studies

Thesis Sponsor/Dissertation Chair/Project Chair

Gregory Pope

Committee Member

Matthew G. Gorring

Committee Member

Joshua Galster

Abstract

Sphericity, hardness, roundness, and size of talus boulders were analyzed to understand the mass wasting process on the Shawangunk Ridge in northwestern New Jersey. Similar studies have been conducted in other localities (e.g., Lassen Peak, California and Spitsbergen, Sweden) but few works were carried out in the eastern United States, particularly in the Appalachian region. During the Pleistocene, ice sheets advanced in North America, and glacial and periglacial (soil and rock affected by ice) environments existed throughout the Appalachians. Although the periglacial climate is not present in this region right now, rock falls are still active where weak joints are affected by freeze-thaw conditions and gravity. Data were collected at different slopes in the ridge by using tape measure and Schmidt hammer. Statistical methods (ANOVA) were used to study the sphericity, hardness and size of rock, and photographic methods are used to study the roundness. The results refute some of previous work on the rock fall processes. For example, many researchers found that sphericity increased downward when rock moved downslope. The talus slope shows a similar trend at some points of the slope but at the base, the rock sphericity decreases, most likely due to weathering and freeze- thaw. Hardness is related to rock size. Pebble contents in the rock reduce rock hardness in the research area. The bigger the rock is, the higher is its Schmidt hammer value. Size decreases and roundness increases downslope. Weathering is high in some sites because of location. Climate plays a more important role in rock weathering on the western side than the eastern side of the ridge because of the prevailing wind that brings moisture. Vegetation is abundant on the west side, and also plays an important role in rock weathering. Steps are distinct géomorphologie features in this area that influence rocks sphericity, hardness, roundness, and sizes. Few angular rocks are found on the western side of the ridge while the eastern side shows the presence of angular rocks. Sphericity decreases at the base on the Yard Creek Power Plant, Sunrise Mountain and Delaware Water Gap.

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