The gas chromatography lab is structured around an Agilent 6890N gas chromatograph with flame inonization detector (FID) and programmable temperature vaporization (PVT) inlet. The GC-FID is primarily used for quantitative analysis of alkenones and other biomarkers in marine sediments. Alkenones are C37 unsuaturated methyl ketones produced by coccolithophorid algae (most commonly by Emiliania hyxleyi) and preserved in the sediment record. The relative concentration of the di- and tri-unsaturated alkenones provides a measure of seawater temperature at the time of growth and deposition and is a widely used method for reconstructing past temperature changes in the world ocean.
Organic extraction of sediments, soils and other samples are carried out with a Dionex ASE 200, using appropriate solvent mixtures. The ASE 200 is a fully automated system capable of fast sample extraction under high pressure and temperature. A sequence of up to 24 samples can be loaded and extracted with minimal operator supervision. Following extraction samples are concentrated by evaporating the solvent with a Zymark Turbovap LV, and prepared for analysis by GC-FID
The centerpiece of the tree-ring lab is a Velmex linear encoder with 0.001 mm precision, QC-10 readout, Clearview MOD-85 stereo microscope with boom stand, and Dell computer running Project J2X data acquisition software. The lab also includes several increment borers for tree coring, drying oven, core mounts, a Makita belt sander for sample sanding and polishing, and other equipment.
Microscopy is used for crossdating and measuring tree-ring samples, and for identifying, picking and preparing foraminifera and other microfossils for analysis. The lab includes two Clearview MOD-85 and one Leica MZ9.5 zoom stereo microscopes. The Leica MZ9.5 is outfitted with a DFC-290 digital camera for image acquisition.
Stable isotope analyses of carbonate samples (foraminifers, corals, speleothems) are carried out in the Optima Laboratory at Lamont-Doherty Earth Observatory of Columbia University. The Optima is an isotope-ratio mass spectrometer equipped with Multiprep carbonate preparation module. It can process 20-30 samples per day and can routinely run samples as small as 8-10 μg with a precision of 0.1 ‰ or better for δ18O, and 0.06 ‰ or better for δ13C.
The ICP-OES lab at Lamont-Doherty Earth Observatory is optimized for routine analysis of Mg/Ca in foraminifera and other carbonate samples (e.g. corals). We use this instrument (Jobin-Yvon Panorama-V) for Mg/Ca work on planktonic foraminifera. Mg/Ca is correlated with seawater temperature at the time of biogenic calcite production and is a valuable method for reconstructing past sea surface temperatures. The ICP-OES lab is under the direction of Dr. Peter B. deMenocal.