Sedimentary Records of Environmental Change Lab  

Welcome 

The Sedimentary Records of Environmental Change Laboratory analyzes physical, biological, and isotopic properties of sediment, especially from lakes and wetlands, to interpret past environmental and climate changes. The laboratory is a shared-use facility, linked to the Amino Acid Geochronology Laboratory, and affiliated with the Colorado Plateau Analytical Laboratory.

The laboratory specializes in analyzing sedimentary:

• biogenic-silica content (wet-alkaline extraction): is a useful climate proxy that can be analyzed rapidly at high resolution. For example, McKay et al. (2008) found that BSi in lake sediment from south-central Alaska was correlated with summer air temperature, and used this relation to quantitatively reconstruct temperature over the last 2000 years. The Sediment Lab analyzes the BSi content of lake and marine sediment collected by collaborating scientists. BSi is extracted from ~100 mg of sediment with 10% Na2CO3 and the concentration is determined with molybdate-blue recution and spectrophotometry following the procedure of Mortlock and Froelich (1989). Contact the lab for pricing information.

• particle-size distribution (Coulter LS230 laser diffraction): is controlled by the prevailing environmental conditions of drainage basin, and by the dynamics of the sediment-transport and depositional systems. The particle-size distribution therefore is a fundamental characteristic of sediment that has been used widely to track environmental changes. Our procedure isolates the minerogenic component of the sediment from biogenic material, and uses a laser-diffraction particle-size analyzer (Coulter LS230) to measure the particle-size distribution. The particle-size distribution is determined by the relative proportion of grain sizes from 2 mm to 0.04 µm, the mean grain size, and the sorting. Contact the lab for pricing information.

• magnetic susceptibility (Bartington MS2 system) 

Laboratory personnel have expertise in:

• purifying diatoms for oxygen-isotope analyses
• taxonomic identifications of freshwater ostracodes
• preparing samples for radiocarbon dating

The laboratory provides opportunities for student training and research.  Laboratory personnel are experienced at preparing samples for isotope analyses, including purifying diatoms and isolating ostracodes for oxygen isotope analyses, and preparing samples for radiocarbon dating by AMS.