The significant and ongoing environmental changes in Arctic regions demonstrate the need for quantitative, high-resolution records of pre-industrial climate change in this climatically sensitive region; such records are fundamental for understanding recent anthropogenic changes in the context of natural variability. Sediment contained within Arctic coastal environments proximal to large fluvial systems has the ability to record paleoclimate variability on subdecadal to decadal scale resolution, on par with many other terrestrial climate archives (i.e. lake sediments, ice cores). Here, we utilize one such sediment archive from Simpson Lagoon, Alaska, located adjacent to the Colville River Delta to reconstruct temperature variability and fluctuations in sediment sourcing over the past 1700 years. Quantitative reconstructions of summer air temperature are obtained using the branched glycerol dialkyl glycerol tetraether (brGDGT)-derived methylation index of branched tetraethers (MBT’)/cyclization ratio of branched tetraether (CBT) paleothermometer and reveal temperature departures correlative with noted climate events (i.e. ‘Little Ice Age’, ‘Medieval Climate Anomaly’). In addition, temporal variability in sediment sourcing to the lagoon, determined using a multi-proxy approach (i.e. granulometry, elemental analysis, clay mineralogy), broadly corresponds with temperature fluctuations, indicating relative increases in fluvial sediment discharge during colder intervals and decreased river discharge/increased coastal erosion during warmer periods. The Simpson Lagoon record presented in this study is the first temperature reconstruction, to our knowledge, developed from coastal marine sediments in the Alaskan Beaufort Sea.
Bibliographical noteFunding Information:
AJMH would like to acknowledge additional support for the 2012 field program provided by the Alaskan Geological Society. The authors thank colleagues Richard Smith, Mike Rodriguez, and Captain Bill Kopplin of the R/V Annika Marie for all of their assistance with the 2010 field work. Assistance during the 2012 field season was provided by Peter Flaig, Dolores van der Kolk, Doug Hissom, and Stephen Hasiotis. They would also like to acknowledge Shannon Loomis for her assistance with the brGDGT statistical analysis, Franco Marcantonio and Luz Romero for assistance with elemental analysis, and Wanda LeBlanc for assistance with the XRD analysis. They also thank John Goff, Terrence Quinn, and Jud Partin for comments on early versions of this manuscript. This research was supported by funding from the National Science Foundation (NSF EAGER grant number ARC-0935336 and NSF grant number ARC-1203851).
This research was supported by funding from the National Science Foundation (NSF EAGER grant number ARC-0935336 and NSF grant number ARC-1203851).
- Colville Delta
- Estuarine sediments
- late Holocene