Sedimentary Geochemistry |
Clean Room and Radiogenic Isotope Laboratory
Stable Isotope Geochemistry | Isotope Paleoecology
Mineral Physics | Computer System | Field Mobility
Analytical Facility for Interdisciplinary Research in EPS
Northwestern University has committed to the renovation of a joint analytical facility, occupying 5,000 square feet, for the analytical needs of Professors Blair, Hurtgen, Jacobsen, Jacobson, Sageman and Smith. The facility will include laboratories for sedimentary geochemistry, aqueous geochemistry, organic geochemistry, stable isotope ratio mass spectrometry (IRMS) radiogenic isotope geochemistry (TIMS), and high-pressure high-temperature mineral physics.
Sedimentary Geochemistry Laboratory (Hurtgen and Sageman)
The sedimentary geochemistry laboratory is equipped to do the following: total organic and inorganic carbon concentrations (UIC carbon coulometer), FeS (acid-volatile sulfide) and pyrite sulfur extractions for concentrations and isotopes (chromium reduction-AVS extraction line), carbonate-associated sulfate (CAS) and barite extractions for d34Ssulfate and d18Osulfate , concentrations of various iron phases (Na-dithionite Fe, HCl-soluble Fe, pyrite Fe, carbonate Fe and total Fe), dissolved sulfate concentrations (ion chromatography), H2S concentrations (via Shimadzu UV-vis spectrophotometer), and concentrations of various Phosphorus phases (SEDEX method, spectrophotometer).
Back to Top
Aqueous Geochemistry Laboratory (Jacobson)
The aqueous geochemistry laboratory supports the elemental analysis (major and trace) of waters, rocks, sediments, soils, and biologic materials. Equipment inlcudes: Dionex DX120 ion chromatograph equipped with an IonPac AS15 column for the measurement of inorganic and organic anions, Milli-Q/Elix 10 water purification system, balances, 3 HEPA filtered benchtop workstations, Orion 250A pH/T/mV/TDS meter, centrifuges, constant temperature water baths, muffle furnace, and drying ovens. Northwestern University also provides centralized analytical services (The Analytical Services Laboratory or ASL) to researchers across a variety of disciplines. Relevant equipment in the ASL includes a Varian Vista MPX ICP-OES with simultaneous CCD detection and a VG Elemental PQ-ExCell quadrupole ICP-MS with collision cell.
Clean Room and Radiogenic Isotope Laboratory (Jacobson)
Positive pressured, HEPA-filtered, laminar flow exhausting hoods are available for the preparation of samples for radiogenic isotope analyses. Supporting equipment includes: Milli-Q/Elix 10 water purification system, 2 HEPA filtered benchtop workstations, balances, centrifuges, rocker table, and hot plates. Plans are underway to build a new facility that will house a Thermo-Finnigan Triton MC-TIMS.
Back to Top
Stable Isotope Geochemistry Laboratory (Blair, Hurtgen, Sageman, and Smith)
The stable isotope geochemistry laboratory is capable of measuring hydrogen, carbon, nitrogen, oxygen and sulfur isotope ratios from a variety of sample materials including organic compounds, bulk organic matter, carbonate associated sulfates, carbonates, waters, dissolved phases, and gases. The facility hosts two ThermoElectron Delta V continuous-flow isotope ratio mass spectrometers (IRMS) with four inlet systems: GC, EA, TC/EA and Gas Bench.
Back to Top
Isotope Paleoecology Laboratory (Smith)
The isotope paleoecology laboratory houses equipment for extraction and characterization of organic molecules from sediments, fossils, and modern organisms for compound-specific isotope analysis via the GC-inlet system of the IRMS. Extractions are accomplished using the Microwave Accelerated Reaction System (CEM MarsX). Samples are then concentrated using the nitrogen evaporators (TurboVap and N-Evap). Compounds are characterized on the quadrupole gas chromatograph mass spectrometer (ThermoElectron Trace-DSQ II GC-MS) equipped with an FID and an autosampler.
Back to Top
Mineral Physics Laboratory (Jacobsen)
Jacobsen's mineral physics laboratory features a suite of high-pressure diamond-anvil cells capable of maintaining static high pressures in excess of 100 Gigapascals, i.e. pressures near the core-mantle boundary at ~2900 km depth. Resistively-heated diamond cells are available for heating up to ~1200 K at simultaneous high pressure and utilized for studies of mineral reactivity at crustal P-T conditions. There is also a 1-atm/2300 K gas-mixing furnace for synthesis at conditions of controlled oxygen fugacity. For deep-Earth studies, laser-heating facilities at nearby Advanced Photon Source of Argonne National Laboratory are employed to reach sample temperatures in excess of 4000 K. At Northwestern, a variety of ultrasonic, spectroscopic, and structural probes are available for in-situ analysis of materials under high pressure and temperature conditions.
Ultrasonic waves generated in the laboratory are used to study the elastic properties minerals and mimic seismic waves in the Earth. These studies are also applied to novel synthetic materials of interest in the materials sciences. The elastic properties of Earth materials govern the speed of seismic waves in the Earth's mantle, and are therefore used to interpret Earth's seismic structure in terms of compositional and mineralogical variability. This laboratory features a unique high-frequency acoustic interferometer including:
- 2-GHz Fluke-6062A RF generator
- Stanford DG535 Pulse Generator
- 6-GHz SMT06 Rhode & Schwarz with internal pulse generator
- HP54121T Broadband digitizing oscilloscope with 18-GHz sampling module
- Plus hardware for interfacing the ultrasonic interferometer to the diamond anvil cell.
The GHz-ultrasonic laboratory is uniquely suited to carry out ultrasonic measurements on samples as thin as 20-30 micrometers and to 10's of GPa pressures in diamond-anvil cells.
A high-resolution optical spectrograph and visible laser system is now under construction in the mineral physics laboratory. In conjunction with near-IR, visible and UV (white) sources, these facilities will be used to study spectroscopic properties of minerals. For example, capabilities will include micro-Raman and optical-UV absorption and reflectivity. High-pressure infrared (IR) absorption spectroscopy is currently being conducted on the U2A synchrotron-IR beamline of the National Synchrotron Light Source, Brookhaven National Laboratory.
Large-scale facilities available to the mineral physics laboratory
The mineral physics laboratory makes extensive used of shared-user, large-scale facilities for high P-T synthesis and studies of mineral structures at high P-T conditions. Sample synthesis is being carried out in the large-volume 5000-ton multianvil press at Bayerisches Geoinstitut in Bayreuth, Germany. Samples loaded in the Northwestern laboratory are routinely taken to the Advanced Photon Source, Argonne National Laboratory for synchrotron X-ray diffraction studies. Neutron diffraction is more suitable for studying hydrogen atom positions in minerals and has been carried out at the pulsed-spallation source (ISIS) at Rutherford Appleton Laboratory near Oxford, UK, and soon we will be using neutrons generated from the new spallation neutron source (SNS) at Oakridge National Laboratory in the US.
Back to Top
The department has an integrated computer network of 30 Linux and Macintosh workstations for research, graduate education, and advanced undergraduate instruction. Student and faculty laptops are also integrated into the network. The integrated network supports the highly interconnected nature of the department. Researchers share common (and often large) global databases and software, faculty and students often work together, students often have multiple advisors, and advanced classes typically use real data in class projects. Most workstations are accessible from each other, and share mass storage and peripherals. These include printers, color plotters (standard and widebed), scanners, and a digitizer.
Back to Top
An outstanding aspect of our research program is the large number of collaborative projects, both within and outside the department. From a geographic standpoint, we have currently active projects in Brazil, Namibia, Newfoundland, the Bahamas, China, the large icebergs of the Ross Sea off Antarctica, the Permian of West Texas, the mountains of the Andes, the Devonian of Western New York, the Wyodak-Anderson coal bed aquifer in Wyoming, the Western Interior of Utah, the Northern Slope of Alaska, Arctic Canada, Northern Minnesota, and the New Madrid Seismic zone in Southern Missouri, as well as the planetary surfaces of Mars, Venus and Mercury.
Back to Top