A New Multielement Method for LA-ICP-MS Data Acquisition From Glacier Ice Cores

To answer pressing new research questions about the rate and timing of abrupt climate transitions, a robust system for ultrahigh-resolution sampling of glacier ice is needed. Here, we present a multielement method of LA-ICP-MS analysis wherein an array of chemical elements is simultaneously measured from the same ablation area. Although multielement techniques are commonplace for high-concentration materials, prior to the development of this method, all LA-ICP-MS analyses of glacier ice involved a single element per ablation pass or spot. This new method, developed using the LA-ICP-MS system at the W. M. Keck Laser Ice Facility at the University of Maine Climate Change Institute, has already been used to shed light on our flawed understanding of natural levels of Pb in Earth?s atmospherepublishersversionPeer reviewe

Alpine ice and the annual political economy of the Angevin Empire, from the death of Thomas Becket to Magna Carta, c. AD 1170–1216

High-resolution analysis of the ice core from Colle Gnifetti, Switzerland, allows yearly and sub-annual measurement of pollution for the period of highest lead production in the European Middle Ages, c. AD 1170–1220. Here, the authors use atmospheric circulation analysis and other geoarchaeological records to establish that Britain was the principal source of that lead pollution. The comparison of annual lead deposition at Colle Gnifetti displays a strong similarity to trends in lead production documented in the English historical accounts. This research provides unique new insight into the yearly political economy and environmental impact of the Angevin Empire of Kings Henry II, Richard the Lionheart and John

Alpine ice-core evidence for the transformation of the European monetary system, AD 640-670

© Antiquity Publications Ltd, 2018. The seventh-century AD switch from gold to silver currencies transformed the socio-economic landscape of North-west Europe. The source of silver, however, has proven elusive. Recent research, integrating ice-core data from the Colle Gnifetti drill site in the Swiss Alps, geoarchaeological records and numismatic and historical data, has provided new evidence for this transformation. Annual ice-core resolution data are combined with lead pollution analysis to demonstrate that significant new silver mining facilitated the change to silver coinage, and dates the introduction of such coinage to c. AD 660. Archaeological evidence and atmospheric modelling of lead pollution locates the probable source of the silver to mines at Melle, in France

Exploration and Development of the Climate Archive of the Allan Hills Blue Ice Area, Antarctica

The ice flow, stable water isotopic composition, and glaciochemistry of ice within the Allan Hills Blue Ice Area (AH BIA), Antarctica, is investigated to determine its potential for contributing to and extending the currently available 800 ka ice core record of paleoclimate. The investigation began with a study of ice dynamics within the AH BIA. The horizontal (u) and vertical (ż) ice velocities, determined using high-precision GPS measurements, are 1.5 to 50 (±0.12) cm a-1 and 2-3 (±0.50) cm a-1, respectively. The significant positive z and low u verify that old ice is present at the surface. Surface topography, in combination with u, was used to delineate a flowline (A-B) along which ice of continuous age was collected for the next stage of the investigation. Surface ice was recovered along 5 km of A-B and a 225 meter core was drilled at its midpoint. Ice samples were analyzed for stable isotopes of water (δD, δ18O), which are common proxies for temperature. The resulting profiles exhibit variability consistent with the magnitude of glacial-interglacial transitions in East Antarctica. These variations, in combination with 40Aratm and δ18Oatm constrain the age of sampled ice to 90-250 ka. However, the 100 meters of directly above bedrock was not collected and the bottom depth is calculated to be at least 400 ka. The final phase of the investigation involved determining the concentrations of terrestrial and marine chemical species in ice from multiple points along A-B. Concentrations ranged from pg L-1 level for rare earth elements to μg L-1 level for multi-sourced compounds like sulfate. The concentrations of all analytes were anticorrelated with stable water isotope values indicating they had preserved a record of changes in atmospheric circulation, source strength, and continental aridity. The composition of rare earth elements points to Australia as an important interglacial dust source, while molar ratios of major ions, particularly Ca2+:Cl- and Mg2+:Cl-, suggest that transport pathways through the McMurdo Dry Valleys cannot be disregarded. In summary, the data collected suggest that ice within the AH BIA is stratigraphically conformable, is older than that recovered in surrounding regions and does contain a well-preserved environmental record

Ultra-high resolution snapshots of three multi-decadal periods in an Antarctic ice core

We offer the first sub-seasonal view of glacial age archives from the Siple Dome-A (SDMA) ice core using the ultra-high resolution capabilities of a newly developed laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS; 121 μm sampling resolution) system capable of conducting multi-element glaciochemical analysis. Our ultra-high resolution data demonstrates that: (1) the SDMA ice core record can be annually dated based on seasonality in chemical inputs at a depth not previously possible using previous glaciochemical sampling methods, (2) winter accumulation at the SD site was greater than summer accumulation during the three late glacial periods selected (∼15.3, 17.3, 21.4 Ka ago) in this study and (3) resulting annual layer thicknesses results show greater variability than the current SD ice core depth/age model (Brook and others, 2005), possibly due to depositional effects such as wind scouring and/or decadal variability in snow accumulation that is not captured by the resolution of the current depth/age model

A New Multielement Method for LA-ICP-MS Data Acquisition from Glacier Ice Cores

To answer pressing new research questions about the rate and timing of abrupt climate transitions, a robust system for ultrahigh-resolution sampling of glacier ice is needed. Here, we present a multielement method of LA-ICP-MS analysis wherein an array of chemical elements is simultaneously measured from the same ablation area. Although multielement techniques are commonplace for high-concentration materials, prior to the development of this method, all LA-ICP-MS analyses of glacier ice involved a single element per ablation pass or spot. This new method, developed using the LA-ICP-MS system at the W. M. Keck Laser Ice Facility at the University of Maine Climate Change Institute, has already been used to shed light on our flawed understanding of natural levels of Pb in Earth?s atmospherepublishersversionPeer reviewe

New LA-ICP-MS cryocell and calibration technique for sub-millimeter analysis of ice cores

Ice cores provide a robust reconstruction of past climate. However, development of timescales by annual-layer counting, essential to detailed climate reconstruction and interpretation, on ice cores collected at low-accumulation sites or in regions of compressed ice, is problematic due to closely spaced layers. Ice-core analysis by laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) provides sub-millimeter-scale sampling resolution (on the order of 100μm in this study) and the low detection limits (ng L–1) necessary to measure the chemical constituents preserved in ice cores. We present a newly developed cryocell that can hold a 1m long section of ice core, and an alternative strategy for calibration. Using ice-core samples from central Greenland, we demonstrate the repeatability of multiple ablation passes, highlight the improved sampling resolution, verify the calibration technique and identify annual layers in the chemical profile in a deep section of an ice core where annual layers have not previously been identified using chemistry. In addition, using sections of cores from the Swiss/Italian Alps we illustrate the relationship between Ca, Na and Fe and particle concentration and conductivity, and validate the LA-ICP-MS Ca profile through a direct comparison with continuous flow analysis results