Coarse-grained Mineral Dust Deposition in Alpine Lake Sediments: Implications for Regional Drought Patterns and Land-use Changes in the Southwest USA
Abstract
Mineral dust accumulation is often causally associated with aridity. However, the relation might not be as straightforward. Consideration of grain sizes and geochemical fingerprinting of the coarse grain fraction will clearly have an impact on how we interpret the sedimentary record of mineral dust in depositional environments e.g. coarse grain fractions of mineral dust would most certainly be transported over relatively short distances and as such in depositional environments, the depositional rate of coarse grains must be determined in order to reliably understand erosional patterns associated with meteorological events (such as frequency of intense wind events such as tornadoes), climatological phenomenon (such as regional droughts) as well as more recently land-use changes. In this study we separate the two size fractions of mineral dust accumulation- fine fraction (typically <4 microns) and coarse fraction (typically >25 microns using grain size analysis from well-studied cores collected from several lake sites distributed across the western southwestern and the Great Plain regions; furthermore we use trace element analysis in each size fraction to identify contributing source regions. We find evidence that the coarser-grain size fraction in the studied lake cores could be of regional origin (and not just local in orgin);. the coarser fraction also appears to be related to intense meteorological events (i.e., the occurrence of cyclones). Analysis is underway to understand the impact of land-use changes on coarse grain fraction
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFMPP31B1276P
- Keywords:
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- 4914 Continental climate records;
- PALEOCEANOGRAPHY;
- 4942 Limnology;
- PALEOCEANOGRAPHY;
- 4944 Micropaleontology;
- PALEOCEANOGRAPHY;
- 4952 Palynology;
- PALEOCEANOGRAPHY