QRC members lead and participate in a wide range of disciplinary and interdisciplinary research projects from the study of past earth climates and glaciations to shifts in the geographic distributions and evolution of vegetation and faunal communities, to the evolution and dispersals of the genus Homo and the increasing scales of human modification of earth environments through the Holocene. QRC provides a venue for meeting and collaborating with scholars across Quaternary disciplines. We are also fortunate to be able to provide seed funding and small grants for member research projects. We are especially happy to support grad student and junior scholar research activities, much of which leads to larger, external funding from agencies like the National Science Foundation.
Illuminating Denali Basal Ice stratigraphy with Electrical Conductivity Measurements
Abstract: North Pacific ice cores have provided critical insights into climate in a region where paleoproxies on >1000-year timescales are difficult to acquire. The Denali ice cores have been particularly impactful, with a robust timescale and demonstrated sensitivity to many critical climate, environmental, and human processes. Until recently the analysis of this record has been limited to the past 1200 years. New data indicates the bottom 10 m of the cores may contain a whole-Holocene record of climate variability. However, developing an accurate timescale for this old and highly compressed ice remains difficult. Here we propose to employ Electrical Conductivity Measurements (ECM) to resolve stratigraphy in remaining core samples. Our goal will be to understand if irregularities in the current timescale are caused by ice folding, or if another process, like climate shifts in the early Holocene, must be responsible. In addition to contributing to the Denali project directly, this work will fit into an ice core community effort to develop techniques extending ice core timescales in basal and disturbed ice.
Constraining ages of glacial deposits recorded in a Victoria Valley permafrost core
Abstract: The past stability of the East Antarctic Ice Sheet (EAIS) remains an important, yet unsettled question. Efforts to address this question focus on EAIS stability during the Pliocene (5.33-2.58 Mya), a period characterized by CO2 levels comparable to today’s levels and global mean temperature comparable to those predicted for the end of the century. While the marine record from the Antarctic Drilling Project (ANDRILL) and recent ice-sheet models suggest a dynamic EAIS during the Pliocene, there is not yet strong corresponding terrestrial evidence of a dynamic Pliocene EAIS. Stratigraphic and geomorphic evidence of glacial deposits from EAIS outlet glaciers in the Antarctic Dry Valleys may provide the much-needed terrestrial record of EAIS stability. Here, a 15-meter ice-cemented permafrost core collected in Victoria Valley is analyzed using cosmogenic nuclides to provide quantitative constraints on the timing of the EAIS glacial history in the Dry Valleys. Based on the presence of oxidized layers from apparent paleosols, the core appears to have recorded four depositional events that are believed to represent different periods of glaciation. Each depositional unit was deposited and exposed to cosmic rays at the surface until subsequently buried during the next glacial event that then shielded the sediment from further cosmic ray exposure. Sediment was subsampled in the core at the upper, middle, and lower limits of each depositional unit and analyzed for 10Be and 26Al, as well as texture, soluble salts, and other parameters. Several possible models of the burial history, accounting for exposure time, burial time, and inherited nuclides, are tested using inverse modeling techniques to provide a timeline for EAIS history in Victoria Valley. Preliminary results of the four units show ages of 30 Ka, 1.05 Ma, 2.4 Ma, and 3.9 Ma, suggesting the earliest expansion of the EAIS coincides with the warmer and wetter conditions during the Pliocene and corroborates the ANDRILL findings.
A search for pre-LGM megaflood sedimentation in Cascadia Basin
Abstract: Marine sediments along the Cascadia margin are likely to contain continuous, long-term records of marine and continental change in the Pacific Northwest over the last several million years. While glaciations, floods, and erosion have reworked the terrestrial record, many marine sites had continuous deposition over this timespan. Such sites are potential archives of oceanographic history, meltwater influx, density-current processes, subduction zone tectonics, and landscape evolution. We propose to study two legacy sediment cores from Cascadia Basin, focusing on depositional chronology and tracers of sediment provenance. The two cores, Deep Sea Drilling Program (DSDP) Sites 174 and 175 are by far the deepest cores from this region, and thus unique in their recovery of sediment spanning multiple glacial-interglacial cycles. This work is a first step towards finding and developing long-term records of megafloods down the Columbia River and understanding Cascadia Basin sedimentation throughout the Pleistocene.
Dating newly suspected MIS2 moraines in Central Asia by CRN
Abstract: Glaciers in Central Asia present an excellent opportunity to test glacier sensitivity to various climate settings. During the global last glacial maximum, around 20,000 years ago, glaciers in southern Siberia and Altay mountains hosted large glacier-dams to originate some of the largest outburst floods on Earth. Central Mongolia shows a similar pattern of glacier advances, in addition to slightly bigger glaciers ~30,000 years ago. In contrast, we have discovered that hyper-arid Gobi glaciated during the warmest period of the early-middle Holocene, with no evidence of glaciations during the coldest of the last ice age. In that condition sunlight provides sufficient energy to evaporate the ice from these precipitation-starved glaciers. This phenomenon was first observed in dry parts of the Kyrgyz Tien Shan, and now we’ve also discovered similar ‘peculiarity’ in the high roofs of Tibet. This project aims to constrain the chronology of glaciers in key locations, and compile a map of paleo-glaciers with different sensitivities.
Abstract: North Pacific ice cores have provided critical insights into climate in a region where paleoproxies on >1000-year timescales are difficult to acquire. The Denali ice cores have been particularly impactful, with a robust timescale and demonstrated sensitivity to many critical climate, environmental, and human processes. Until recently the analysis of this record has been limited to the past 1200 years. New data indicates the bottom 10 m of the cores may contain a whole-Holocene record of climate variability. However, developing an accurate timescale for this old and highly compressed ice remains difficult. Here we propose to employ Electrical Conductivity Measurements (ECM) to resolve stratigraphy in remaining core samples. Our goal will be to understand if irregularities in the current timescale are caused by ice folding, or if another process, like climate shifts in the early Holocene, must be responsible. In addition to contributing to the Denali project directly, this work will fit into an ice core community effort to develop techniques extending ice core timescales in basal and disturbed ice.