24 Lake Sedimentary Records of Past Climate and Environment (Posters)

This session will focus on lacustrine archives and reconstructions of past environmental changes through the use of geochemical, biological, and sedimentological proxies. Both modern and paleo proxy datasets are welcome.

Monday, 23 March 2026
8:00 AM - 12:00 PM
CCC, Ballroom C

Holocene Climate Variability in Northeast Greenland inferred from Sedimentary Leaf Wax Hydrogen Isotopes

Paper number: 24-20
Program: Technical Sessions
Time: 8:00 AM – 8:00 AM

Authors

Abstract

Lacustrine sediments from the Arctic are important archives of past climate variations and ecosystem changes. Here we present a 7.5 kyr record of leaf wax (n-alkane) distributions and their hydrogen isotope (δ2H) values from lake Latesommersø, NE Greenland. Latesommersø (82.23°N, 33.52°W) is located in Wandal Dal, a 50 km-long valley that drains meltwater from the Greenland Ice Sheet and several small ice caps. The δ2H values of long chain n-alkanes (C29 and C31) show little variation over the last 7500 yrs, while δ2H values of mid-chain n-alkanes (C25 and C27) show greater variability. The temporal trends in the δ2H values of the various n-alkanes suggest a mixture of two different hydrogen isotope signals. To disambiguate these isotope signals, we apply an unmixing approach using non-negative matrix factorization (NMF) to evaluate the changing source contributions of individual n-alkanes to Latesommersø sediments through time. We then use the NMF results to develop a model for a purely terrestrial (δ2Hterr) and a purely aquatic (δ2Haq) n-alkane δ2H record. The δ2Hterr record, interpreted as δ2H of summer-biased precipitation, reveals increasing δ2H values between 7-5 ka, followed by long term cooling with multicentennial-scale minima centered at 3.5 ka, 2.3 ka, and 1.5 ka. This δ2Hterr record shows a striking similarity to marine-based records of Atlantic Water advection (Werner et al., 2013) and sea ice extent (Müller et al., 2012) in eastern Fram Strait, suggesting that isotopes in precipitation in Northeast Greenland have tracked the location and temperature of source-water evaporation. This study provides an important new record of isotopes in High Arctic precipitation and demonstrates the utility of NMF-based isotope unmixing in leaf wax studies. 

 

Müller, J., Werner, K., Stein, R., Fahl, K., Moros, M., & Jansen, E. (2012). Holocene cooling culminates in sea ice oscillations in Fram Strait. Quaternary Science Reviews, 47, 1–14.

Werner, K., R. F. Spielhagen, D. Bauch, H. C. Hass, & E. Kandiano (2013). Atlantic Water advection versus sea-ice advances in the eastern Fram Strait during the last 9 ka: Multiproxy evidence for a two-phase Holocene. Paleoceanography, 28, 283–295.

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

doi: 10.1130/abs/2026NE-411362

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