229 Crustal Petrology (Posters)

This session explores various igneous and metamorphic processes that have shaped Earth’s crust. We welcome contributions from the micro- to macroscale, from the deep to shallow crust, and from field- to laboratory- to modeling-based.

Tuesday, 21 October 2025
8:00 AM - 5:30 PM
HBGCC, Hall 1

Mapping Archean Crust: Esker Zircon Geochronology in the Under-explored NW Slave Province

Paper number: 229-10
Program: Technical Sessions
Time: 8:00 AM – 8:00 AM

Authors

Abstract

Our understanding of the evolution of Earth’s earliest continental crust is limited by a scarcity of preserved crust from the Archean and earlier.  Sediments derived from Archean continental crust provide useful samples to investigate the processes that shaped Earth’s early lithosphere.  One such region of Archean crust is the western Slave craton in NW Canada which hosts the Acasta Gneiss Complex and the Eokuk Uplift which contain crust 4.02 and 3.81 billion years old, respectively (Reimink et al., 2018; Stoian, 2022).  Sandwiched between these terranes is the Napaktulik Lake region, an under-explored section of Archean crust with an uncertain distribution of ages and lithology.  Notably, the western Slave Craton tends to host older rocks, therefore, has potential to yield yet undiscovered >3.75-billion-year-old crust.

This study uses glacial eskers as a natural sampling tool to investigate the characteristics of crust (Bilak et al., 2019) in the Napaktulik Lake region.  Glacial eskers are meandering ridges of glaciofluvial sediment, which provide a mechanism to sample large areas of underlying bedrock eroded by the upstream glacier.  We collected two samples along a late Pleistocene-aged esker and isolated >400 detrital zircons from each.  Using laser ablation split-stream inductively coupled plasma mass spectrometry (LASS-ICPMS), we measured the U-Pb age distribution and trace element composition for individual detrital zircons grains. 

The zircon data from the Napaktulik Lake region esker will then be compared to exposed basement gneiss zircon data from the Acasta Gneiss complex (Reimink, 2018) and the Eokuk uplift (Stoian, 2022).  We map the extent of the exposed basement gneisses underlying the Napaktulik Lake Region to help enhance our understanding of Earth’s first continental crust. This data can be further used to evaluate the potential to use esker detrital zircon grains as an early-earth prospecting approach, mirroring the utility of eskers as mineral prospecting tools.

 

Reimink et al., Earth’s Oldest Rocks (2018)

Bilak, G. et al., Geochemistry, Geophysics, Geosystems (2022)

Stoian, C., MSc Thesis, Penn State University, 2022

Geological Society of America Abstracts with Programs. Vol. 57, No. 6

doi: 10.1130/abs/2025AM-414046

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