24 Mapping in the Geosciences: Processes and Products (Posters)

Monday, 18 March 2024
9:00 AM - 1:00 PM
Armory Ballroom

SURFICIAL GEOLOGIC MAP OF THE MOUNT MOOSILAUKE 7.5' QUADRANGLE, NEW HAMSPHIRE

Paper number: 24-1
Program: Theme Sessions
Time: 9:00 AM – 1:00 PM

Authors

Abstract

The Mount Moosilauke 7.5-minute quadrangle in the western White Mountains extends from 44o00'00" to 44o07'30" N, and from 71o45'00" to 71o52'30" W. The quadrangle encompasses parts of the towns of Lincoln, Easton, Landaff, Woodstock, and Benton. Most of the quadrangle lies within the White Mountain National Forest, with a small area in the south-central part on Mount Moosilauke owned by Dartmouth College. Surficial deposits include unconsolidated glacial and non-glacial sediments, such as clay, silt, sand, gravel (pebbles to boulders). Most of these sediments were deposited during and after the late Wisconsinan glaciation, which began about 25,000 years ago. The topography of the quadrangle is hilly to mountainous, with Mount Moosilauke in the south-central part of the area the most dominant landform. At 4802 ft, Mount Moosilauke is the 10th tallest and 3rd most prominent peak in New Hampshire. Surficial geologic map units include stream alluvium, alluvial fan deposits, wetland deposits, landslide deposits, colluvium (talus slopes), stream terrace deposits, ice-contact stratified deposits, eskers, glacial-lake sediments, block fields, till, and moraines. Continental ice covered Mount Moosilauke during the late Wisconsinan glaciation. About 50 to 60 benches extend from near Mount Moosilauke’s summit down to about 2200-ft elevation, well below Ravine Lodge in the Mount Kineo quadrangle. The benches range in height from 2 to 35 ft with an average spacing of 212 linear feet (n = 60). Many segments of these benches are parallel to contours and the segments can be traced for thousands of feet with little elevation change across drainages and even across the floor and walls of Jobildunk Ravine, the best developed cirque on the mountain. We believe that these benches are composed of till and were deposited along the margins of the continental ice sheet that lowered too rapidly during deglaciation to allow formation of moraines. In concordance, correlation of ice-contact deposits at several locations of similar elevation across valleys and watersheds also suggests that deposition occurred in contact with a waning remnant of the continental ice sheet. The most prominent post-glacial landforms in the Mount Moosilauke quadrangle are the extensive landslide tracks and deposits that occur on steeper slopes.

Geological Society of America Abstracts with Programs. Vol. 56, No. 1

doi: 10.1130/abs/2024NE-396951

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