The origin of the King Ravine Rock Glacier in the Presidential Range of the White Mountains of New Hampshire

No positive evidence for post-Wisconsin periglacial or alpine glacial activity has been found anywhere in New England except in King Ravine in the Presidential Range of New Hampshire. The floor of the King Ravine cirque is occupied by a relict rock glacier. Rock glaciers are usually either glacial or periglacial in origin. The surface features of the King Ravine rock glacier, including lithology, orientation of blocks, lichens, and weathering, were studied to help determine its age and mode of formation. The proposed origin of the King Ravine rock glacier is as an icecored rock glacier that was active during the last deglaciation in New Hampshire. The rock glacier probably started to grow when most of the continental ice in New Hampshire had disappeared. King Ravine is a northfacing cirque and may have provided better protection from solar radiation for remnant ice than any of the other twelve cirques in the Presidential Range. Blocks falling from the headwall onto a remaining ice mass may have caused it to flow outward for a short distance (about 1800 feet). The blocks that make up the surface of the rock glacier are too big to have been arranged as they are now by periglacial frost action, and perched boulders suggest that glacial ice played a part in moving some of the material. A slight deterioration in climate may have promoted the growth of a very small cirque glacier, less than 1800 feet long, which advanced over most of the pre-existing rock glacier. The front of this glacier halted and became an ice-cored rock glacier atop the first, and a small ice glacier remained at its head for a short time. When the glacier ice melted away, furrows and pits appeared on the surface of the rock glacier. The resulting feature is the relict rock glacier that exists in King Ravine now.