Arctic Environmental Change across the Pliocene-Pleistocene Transition

Keisling, Benjamin Andrew

Publication:
Arctic Environmental Change across the Pliocene-Pleistocene Transition

dc.contributor.advisor	Isla S. Castañeda
dc.contributor.author	Keisling, Benjamin Andrew
dc.contributor.department	University of Massachusetts Amherst
dc.contributor.department	Geosciences
dc.date	2024-03-28T20:24:15.000
dc.date.accessioned	2024-04-26T18:16:37Z
dc.date.available	2024-04-26T18:16:37Z
dc.date.submitted	May
dc.date.submitted	2015
dc.description.abstract	Environmental change in the Arctic proceeds at an unprecedented rate. The Pliocene epoch (5-2.65 million years ago) represents an analog for future climate conditions, with pCO2 and continental configurations similar to present. Yet conditions in the Pliocene Arctic are poorly characterized because of sparse sampling. The records that do exist indicate periods of extreme warmth, as well as the first expansion of large ice-sheets in the Northern Hemisphere, took place from the end of the Pliocene into the early Pleistocene. Understanding these deposits and their implications for our future requires developing a sense of climatic evolution across the Plio-Pleistocene transition and especially during the intensification of Northern Hemisphere Glaciation (iNHG) ~2.7 million years ago. Here we reconstruct environmental change in the Arctic using a suite of organic geochemical proxies in a sedimentary archive recovered from Lake El'gygytgyn, Arctic Northeast Russia. We use the distribution of branched glycerol dialkyl glycerol tetraethers (brGDGTs) and the hydrogen isotopic composition (δD) of plant leaf-waxes (n-alkanes) to reconstruct relative temperature change across the interval spanning 2.8 to 2.4 million years ago. Our work demonstrates that, following the first major glaciation of the Northern Hemisphere, it took multiple glacial cycles for the Arctic to become synchronized with the climatic changes recorded in the deep ocean. This work has implications for understanding the role of sea-level, sea-ice, vegetation and carbon-cycle feedbacks in a changing Arctic.
dc.description.degree	Master of Science (M.S.)
dc.identifier.doi	https://doi.org/10.7275/6955394
dc.identifier.orcid	N/A
dc.identifier.uri	https://hdl.handle.net/20.500.14394/33219
dc.relation.url	https://scholarworks.umass.edu/cgi/viewcontent.cgi?article=1223&context=masters_theses_2&unstamped=1
dc.source.status	published
dc.subject	Arctic
dc.subject	biomarker
dc.subject	paleoclimate
dc.subject	ice sheets
dc.subject	GDGT
dc.subject	leaf wax
dc.subject	Biogeochemistry
dc.title	Arctic Environmental Change across the Pliocene-Pleistocene Transition
dc.type	openaccess
dc.type	article
dc.type	thesis
digcom.contributor.author	isAuthorOfPublication\|email:bkeisling@geo.umass.edu\|institution:University of Massachusetts Amherst\|Keisling, Benjamin Andrew
digcom.identifier	masters_theses_2/228
digcom.identifier.contextkey	6955394
digcom.identifier.submissionpath	masters_theses_2/228
dspace.entity.type	Publication