Geochemistry and Geomaterials Research Laboratories (GGRL)

Wet Chemistry Laboratory

The Wet Chemistry Laboratory specializes in the broad-spectrum inorganic analysis of water, gas, and solid samples. Several organic compounds such as water-soluble tracers and high explosives can also be determined. Examples of past and present applications include analysis of fluids for geothermal system exploration; fluid analysis and remote sensing in volcano research; environmental water and soil analysis; and studies involving organic and inorganic tracers in water and solid materials. Central to the laboratory is an Inductively Coupled Plasma (ICP) Atomic Emission Spectrometer and an ICP-Mass Spectrometer fitted with an auxiliary laser ablation sampler. Other instrumentation includes Atomic Absorption, Ion Chromatography (for anions in water, rock fusions, and gas caustics), High-Pressure Liquid Chromatography (organic tracers, high explosives), Gas Chromatography for non-compressible gases; and Total Carbon Analysis for organic and inorganic carbon in liquids and solids.

X-ray Diffraction Laboratory

X-ray diffraction (XRD) is the preferred method for phase identification as it provides unambiguous solid-phase information. EES-6 has made substantial contributions to quantitative X-ray diffraction methods. The Rietveld quantitative analysis method was pioneered in our laboratory, as were other major enhancements. We also recently developed a revolutionary new full-pattern quantitative XRD method that is flexible and easy to use, yet produces precise and accurate results. XRD samples can be analyzed at temperatures from liquid-N2 to 300­C, in vacuum or inert-gas atmospheres. Experiments can alsobe conducted under precisely controlled humidity conditions from 0-100% relative humidity using an EES-developed computer-automated humidity control system.

This system is particularly useful for analysis of hydrous phases such as clay and zeolite minerals. We have used XRD to measure structural changes of minerals during heating and water sorption/desorption, to perform crystallite size/strain measurements, and to detect trace amounts of hazardous minerals (e.g., erionite down to ~250 ppm). We have also used the lab to determine and refine several mineral crystal structures and for the identification of yoshiokaite, a new mineral obtained from the surface of the Moon.

Constant-flow-rate pumps are used to produce pulse-free flow of water and non-aqueous-phase liquid (NAPL) mixtures through the cores. Currently, accurate flow rates of 0.02 to 800 cc/min can be achieved. Absolute and relative permeabilities are measured using differential pressure gauges connected to pressure taps positioned at selected lengths along the core.

Thermal Analysis

The EES-6 thermal analysis capability consists of a suite of instruments including thermogravimetric analyzers (TGA, which monitors the weight of a sample as a function of a change in temperature and/or atmosphere), a differential scanning calorimeter (DSC, which monitors the heat flow from a sample as a function of temperature and/or atmosphere), and a moisture evolution analyzer (MEA, which measures the water content of a sample). In addition, the laboratory has a full suite of teflon-lined pressure vessels, including Parr vessels, for elevated-pressure experiments. A unique feature of the laboratory is a VG quadruple mass spectrometer that is linked directly to the TGA instrument to determine the composition and abundance of gases evolving while heating a sample.

Optics

The GGRL has an extensive suite of optical equipment including a fluid inclusion heating stage and microscope, a cathodoluminescence microscope, a Fourier-transform infrared spectrometer with conventional and microscope stages, and a complete suite of optical microscopes for analysis of geologic thin sections.

Light Stable Isotope Laboratory

EES-6 has a new Micromass IsoPrime Continuous-Flow Isotope Ratio Mass Spectrometer. This instrument is a highly automated, high throughput system that represents the cutting edge in continuous-flow light stable isotope mass spectrometry. With this system, we are able to conduct various measurements on oxygen, carbon, nitrogen, and hydrogen isotopes in waters, carbonates, soils, dissolved inorganic carbon (DIC), bulk organic materials, etc.

This system fills in gaps in our current geochemical capabilities and has already been lined up to assist in studies of carbon sequestration, water cycles, and to support ocean modeling efforts. The instrument can also be used for biogeochemical studies, potentially for threat reduction, for contaminant tracing, and potentially to measure isotopically labeled compounds used in biological studies.

Electron Microanalysis

The Cameca SX50 Electron Microprobe is a nondestructive analysis technique for quantification of materials and mineral phases in situ at the micrometer level. Quantification of elements Be through U is possible with a routine sensitivity of 0.01 element wt. %. Typical specimens are geologic minerals, metals, ceramics, glasses, and cements. Specimens may be examined in either transmitted or reflected light, and scanning mode is also available. The ADEM Scanning Electron Microscope (SEM) is used primarily to characterize textural and chemical features of materials at the micrometer level. This SEM has the unusual capability to examine large specimens (approx. 6î x 3î x 3î) as well as to examine specimens in an uncoated condition.

X-ray Fluorescence Laboratory

X-ray fluorescence analysis is the primary method EES-6 uses for characterizing the major-, minor-, and trace-element geochemical content of bulk solids. Typical quantitative analyses include wt% of Si, Al, Fe, Mg, Mn, K, Na, Ca, P, and Ti, as well as ppm measurements for V, Cr, Ni, Zn, Rb, Sr, Y, Zr, Nb, and Ba.

Contacts

All Laboratories

Steve Chipera at 505-667-1110 or chipera@lanl.gov
George Guthrie at 505-667-1110 or gguthrie@lanl.gov

Thermal Analysis

David Bish at 505-667-1165 or bish@lanl.gov

Light Stable Isotope Laboratory

Jeff Heikoop at 505-667-8128 or jheikoop@lanl.gov
Don Hickmott at 505-667-8753 or dhickmott@lanl.gov

X-ray Fluorescence Laboratory

Emily Kluk at 505-665-8788 or ekluk@lanl.gov

Electron Microscopy

Peg Snow at 505-667-8007 or snow@lanl.gov

Wet Chemistry Laboratory

Dale Counce at 505-667-1224 or counce@lanl.gov

Field Analysis of CO2

Manvendra Dubey at 505-665-3128 or dubey@lanl.gov

LAP 02-189