143-2 Sedimentology, Stratigraphy, and Geochemistry of Marine Glendonites in the Mount Goodenough Formation, Northwest Territories, Canada

Abstract:

The identification of the hydrated mineral ikaite (CaCO₃·6H₂O) and its polymineralic pseudomorph, glendonite, is frequently used as a proxy for cold water temperatures in ancient sedimentary successions. In recent years, however, experimental work has shown that a variety of other factors, such as methane release, may drive metastable ikaite precipitation in marine sediments without requiring near-freezing conditions. We discovered abundant glendonites throughout the type area of the Lower Cretaceous Mount Goodenough Formation in the Aklavik Range of Northwest Territories, Canada. In addition to being the first detailed report of these features in Cretaceous rocks of the Beaufort Sea area, the glendonites are also intimately associated with methane and/or hydrocarbon seep carbonates and local tephra horizons. Here, we characterize the sedimentology and stratigraphy of the Mount Goodenough Formation in its type area. Second, we present new whole-rock geochemical results from Mount Goodenough mudstones, as well as new carbonate carbon and oxygen isotopic data from the glendonites and seep carbonates. Finally, we present new zircon U-Pb ages from the Mount Goodenough tephras that confirm its Barremian depositional age and point to potential distal volcanic products from the High Arctic large igneous province (HALIP). These new data ultimately provide new insight into the reliability of ikaite as a temperature proxy and provide new paleoclimatic information for the Canadian Arctic margin in the Early Cretaceous.

© Copyright 2026 The Geological Society of America (GSA), all rights reserved.