Abstract

Controversy persists in western Newfoundland regarding Pleistocene, particularly Late Wisconsinan, glacial ice volumes. Independently, a set of alpine glacial deposits on the flanks of the Tablelands in Gros Morne National Park has attracted much attention but little scrutiny. In this study, cosmogenic nuclide dating of the alpine deposits places some limits on post-late glacial maximum (LGM) ice dynamics in the vicinity of the Tablelands, a plateau bounded on the northeast by Trout River Gulch. Small valleys incised into the flanks of the Tablelands are floored with a diamict that contains both till and ice-contact deposits. Rock glaciers rest on the diamict, and rock glacierization also has affected talus lining the south wall of Trout River Gulch. A small moraine rests in the Devil’s Punchbowl cirque. The cirque moraine, lobate deposits below the cirque moraine, rock glaciers, and a colluvial veneer overlying the till in the small valleys have cosmogenic 36Cl ages as old as either ca. 20 or 15 ka, depending on what erosion rate is assumed, indicating that these bodies are Late Wisconsinan in age but post-date the local LGM. Trout River Gulch was deglaciated early and perhaps did not contain active ice even at the LGM, but previous work shows that ice was streaming seaward both north of Trout River Gulch and south of the Tablelands even as the gulch lay relatively ice free.

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