Applications for Ultra-High Resolution Glaciochemical Records From High Altitude Mountain Glaciers
Abstract
Use of novel, non-destructive technological advancements in ice core sampling and analysis reveals valuable and detailed climate information that traditional methods (e.g., IC, ICP-MS) are unable to capture. Using the Climate Change Institute's W. M. Keck Laser Ice Facility laser ablation-inductively coupled plasma-mass spectrometer (LA-ICP-MS), we achieve a realistic measure of variability of select chemical species at ultra-high resolution (as low as 121 mm) that is also non-destructive to ice cores. Here we present two applications for LA-ICP-MS data: annual layer counting of highly compressed near basal ice from Peru (Quelccaya Ice Cap) and meteorological scale event investigation of an ice core from the Swiss-Italian Alps (Colle Gnifetti glacier). Additionally, we use targeted (4 m) LA-ICP-MS measurement of dust elements (Mg, Ca, Fe) to verify annual layers and observe seasonality changes in highly compressed ice records from an ice core (~37 m) drilled in 2016 in the Pamir Mountains of Central Asia.
We measured a combination of sea-salt (Na) and dust (Fe, Al, Mg) elements (36 cm) from a near basal ice core (5 m) drilled at the base of the Quelccaya Ice Cap in 2018. These measurements reveal annual layer thickness where layers are highly thinned. Our initial observations of the annual layers indicate a thickness of approximately 0.005-0.015 m where the section of basal ice is dated to 60 C.E., using 14C measurements, suggesting there may be more years in the Quelccaya record than previously suggested. Using the Colle Gnifetti ice core drilled in 2013, we collected a total of 316,000 data points per element continuously over 20m of this core (1 -1820 C.E.), providing the longest continuous summer Saharan dust record thus far available and on sub-annual to sub-seasonal event scales. We focus here on the relative phasing of elements (Fe, Al, Mg, Ca, Pb, Cu, Na) where sample resolution is on the order of 500-1000 data points per year. Our initial results of dust elements demonstrate Fe, Ca and Al in phase while Mg shows peaks not observed in other dust elements, which could be indicative of a separate source. Out of phase from dust elements, Na corresponds with Cu and Pb, suggesting heavy metals could transport with sea-salt coming from the North Atlantic. We acknowledge NSF/Acadia Fund for funding this research.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.C11C1301C
- Keywords:
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- 0724 Ice cores;
- CRYOSPHERE;
- 1615 Biogeochemical cycles;
- processes;
- and modeling;
- GLOBAL CHANGE;
- 1616 Climate variability;
- GLOBAL CHANGE;
- 4994 Instruments and techniques;
- PALEOCEANOGRAPHY