35-16 Assessing the Geomorphic Identity of the Talus Deposit in King Ravine in the Presidential Range of New Hampshire

Session: Ice sheets, glaciers, and landscapes, oh my! (Posters)

Poster Booth No.: 49

Presenting Author:

Margaret Keating

Authors:

Keating, Margaret Miller¹, Palucis, Marisa C.², Getraer, Alexander³, Kelly, Meredith A.⁴, Hawley, Robert⁵, Robbins, Liesel S.⁶, Getraer, Benjamin⁷

(1) Department of Earth Sciences, Dartmouth College, Hanover, , (2) Department of Earth Sciences, Dartmouth College, Etna, , (3) Department of Earth Sciences, Dartmouth College, Hanover, , (4) Department of Earth Sciences, Dartmouth College, Hanover, , (5) Department of Earth Sciences, Dartmouth College, Hanover, , (6) Department of Earth Sciences, Dartmouth College, Hanover, , (7) Department of Earth Sciences, Dartmouth College, Hanover, ,

Abstract:

For over a century, geologists have debated whether local cirque glaciers in the White Mountains of New Hampshire were active following Laurentide Ice Sheet retreat. This debate includes questions about the origin of alpine cirques in the Presidential Range. King Ravine, on the north side of the range, near Randolph, New Hampshire, contains a tongue-shaped deposit on the valley floor that past research has inconclusively interpreted as a rock glacier. However, we know very little about this feature’s origin or composition. Here, we apply remote sensing data, ground penetrating radar (GPR), and 10Be cosmogenic nuclide exposure dating to investigate 1) whether this feature is a rock glacier (active, inactive, or relict), and 2) when and under what conditions it formed. Using LiDAR and high-resolution imagery we create a detailed surficial map of the landform and other surficial features within King Ravine. We use low frequency radio-echo sounding across the talus lobe to make depth and volume calculations, and describe the internal composition that characterizes the feature. Finally, we use surface exposure ages to constrain the timing of feature formation, and correlate lake sediment records and other paleoclimate proxies to infer the environmental conditions at that time. We combine these approaches to evaluate the geomorphic origin of the talus deposit in King Ravine, and to assess whether it reflects a post-Laurentide cirque glacier origin. 

Geological Society of America Abstracts with Programs. Vol. 58, No. 2, 2026

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