Blowing in the late Cenozoic wind—detrital zircon river contributions to an interior Alaska loess deposit. (1st January 2022)

• Record Type: Journal Article
• Authors: Nadin, Elisabeth; Goddard, Scott; Benowitz, Jeff; O'Sullivan, Paul
• Is Part Of: Quaternary science reviews. Volume 275(2022)
• Publication Date: 2022-01-01
• Subjects: Detrital zircon -- Loess -- Interior Alaska -- Winds -- River zircon ages; Geology, Stratigraphic -- Quaternary -- Periodicals; Stratigraphie -- Quaternaire -- Périodiques; 551.79
• DOI: 10.1016/j.quascirev.2021.107266
• Languages: English
• ISSNs: 0277-3791

Abstract

Abstract: The extensive Interior Alaska loess deposits record glacial advance and retreat over the past 3 Myrs. Refining our understanding of the still-debated origins of this loess will help us refine our understanding of climate patterns since the late Cenozoic. We present here the first detrital-zircon ages from the Gold Hill loess, a well-studied deposit in Fairbanks, Alaska, as well as new detrital-zircon ages from local fluvial sediments. We describe a new statistical approach to quantify the contributions of sediment loads from local rivers to account for the grain-age distributions within the Fairbanks loess. We find that zircons from the 3 Ma base of the loess deposit come mainly from sediments carried by the Tanana and Delta rivers, and Yukon River sediments contributed more zircons over time as this river system developed. This indicates that loess-depositing winds in Interior Alaska came from the east/southeast, a pattern that persists today. Although we cannot exclude other sources, our new statistical approach suggests that a mix of sediments carried from local river deposits can account for almost all of the zircon grains in the Gold Hill loess deposit of interior Alaska. Highlights: Interior Alaska loess deposits that span 3 Myrs yield robust populations of detrital zircons. Loess deposit grain-age distributions can be reconstructed from grain-age distributions of local river deposits. The Tanana-Delta and Yukon rivers were the main contributors of sediment to the Gold Hill loess deposit since the late Pliocene. The river source areas of the Gold Hill loess deposit are consistent with modern seasonal wind directions in Alaska.