Evolution of the central West Greenland margin and the Nuussuaq Basin: Localised basin uplift along a stable continental margin proposed from thermochronological data

Abstract

The Late Cenozoic is typically considered a time of widespread episodic tectonic uplift along the West Greenland continental margin (36-2 Ma), similar to other margins across the North Atlantic, such as Norway, East Greenland and the UK. The present study re-examines and remodels onshore thermochronological data from central West Greenland and the Cretaceous Nuussuaq Basin, utilising a Bayesian modelling approach and new concepts related to radiation damage within apatite. These new thermal histories indicate that slow-protracted cooling has occurred across the southern extent of the margin during the Mesozoic and Cenozoic, whereas those from within the Nuussuaq Basin display reheating through the Late Cretaceous/Palaeogene and cooling to present. Results suggest that no significant Late Cenozoic uplift has occurred along the southern margin, while cooling in the Nuussuaq Basin is consistent with events outlined in the basin's stratigraphy and implies uplift during volcanism and an isostatic response to the unroofing of the lithosphere has elevated the modern topography. These results imply significant tectonism in the region ceased by~45 Ma, yet have wider implications regarding how low temperature thermochronology data are treated and our understanding of the postrift evolution of passive margins. K E Y W O R D Smodelling, passive margins, stratigraphy, tectonics and sedimentation, thermochronology

The source of topography across the Cumberland Peninsula, Baffin Island, Arctic Canada: differential exhumation of a North Atlantic rift flank

“…Across the continental margins of Baffin Bay and the Labrador Sea AFT and AHe ages appear similar to those reported here (Hendriks et al, 1993;Japsen et al, 2006;McDannell et al, 2019;Jess et al 2019), while the interpretation of rift related uplift and differential erosion shaping the landscape is comparable (Hendriks et al, 1993;Jess et al 2019). AFT data from both Newfoundland and West Greenland are interpreted to suggest the modern topography is the result of rift-related uplift (Hendriks et al, 1993;Jess et al, 2019), while low rates of exhumation during the Cenozoic are inferred from thermal modelling of both AFT and AHe data (Jess et al 2018). Collectively this suggests much of the topography observed across the wider region is likely the result of preserved rift-related uplift, such that both margins have evolved according to a single unifying conceptual model that does not require the intervention of post-rift uplift.…”

The Northwestern Greenland Ice Sheet During The Early Pleistocene Was Similar To Today

“…He in apatite is partially retained at temperatures below ~70–90 °C—corresponding to shallow depths (<3 km) in Earth's crust—and completely retained below ~30‐40 °C, depending on mineral chemistry and cooling rate (Farley, ; Flowers et al, ; Shuster et al, ). Detrital apatite studies of glacial sediments can detect deep glacial valley/fjord incision that excavated apatite grains with young AHe ages (Bernard et al, ; Jess et al, ; Tochilin et al, ). We analyzed 10 detrital apatite grains to investigate whether deep glacial incision along the NW GrIS had produced young AHe ages.…”

Innovations in (U–Th)/He, Fission Track, and Trapped Charge Thermochronometry with Applications to Earthquakes, Weathering, Surface‐Mantle Connections, and the Growth and Decay of Mountains

“…Low‐temperature thermochronometry provides new perspectives on the relative importance of lithospheric flexure, isostasy, and structural inheritance controlling escarpment development and degradation. Examples of FT and (U–Th)/He thermochronometry applications to passive margins include southern Africa (Brown et al, , ; Brown et al, ; Cockburn et al, ; Flowers & Schoene, ; Gallagher & Brown, ; Kounov et al, ; Tinker et al, ; Wildman et al, ), Fennoscandia (Hendriks & Redfield, ), Brazil (Gallagher et al, ; Hackspacher et al, ), and Baffin Island and West Greenland (Japsen et al, ; Jess et al, ; Jess et al, ).…”