High resolution Holocene temperature records for the northeastern United States from hydrogen isotope ratios of mid-chain aquatic plant lipids

Holocene temperature changes for the northeastern U.S. are poorly defined due to the lack of suitable proxies. We developed a mathematic model to quantify the percentage contribution of aquatic plants to the mid-chain n-alkyl lipids in lake sediments (Gao et al., GCA, 2011). We show that Little Pond in Royalston, Massachusetts is characterized by exceptionally high percentages (>90%) of aquatic contribution to the mid-chain n-alkyl lipids in sediments, and generated a quantitative, high-resolution Holocene temperature record based on compound-specific D/H ratio of behenic acid (δDBA) (Figure). Our record shows that the Laurentide Ice Sheet suppressed the regional temperature by ~ 2 °C during the early Holocene. Numerous rapid and large (~4.9 °C) climate oscillations occurred as a result of major freshwater outbursts and the resulting changes in North Atlantic meridional overturning circulation. Following a major climate reversal at 8.2 ka, the regional climatic optimum occurred between ~8 ka and ~7 ka BP. Temperature gradually declined from ~8ka toward present by ~3.9 °C associated with the declining summer insolation. During the past two millennia, temperature changes closely mimic the synthesized borehole temperatures, with a temperature trough at ~1.8 ka and a peak at ~0.5 ka. Regional temperature does not show the typical little ice age trends, except a minimal temperature (~7 °C) at ~1850 A.D, which is followed by rapid temperature rise probably as a result of anthropogenic forcing. Combined with our previous data from Blood Pond, we have obtained centennial scale temperature history for the New England region for the past 15000 years.