Plasma Mass Spectrometry
Isotope Geochemistry and Geochronology
Neutron Activation Analysis
Laboratory for Noble Gas Geochronology
Organic Geochemistry Laboratory
ACES: Alliance for Computational Earth Science
Geophysical Fluid Dynamics (GFD) Laboratory
MIT Paleomagnetism Laboratory
EAPS operates quadrupole and multicollector sector mass spectrometers under the direction of Professor Ed Boyle. These instruments use a high temperature argon plasma to ionize elements from aqueous and gaseous samples prior to mass spectrometric analysis. The Micromass IsoProbe multicollector mass spectrometer is used to rapidly determine precise isotope ratios for lead, iron, hafnium, uranium, thorium, and other refractory elements. Its efficient hexapole transmission allows it to be used for highly sensitive (e.g. parts per trillion) analysis of trace elements in environmental samples with a minimum of interferences. Our VG PQ2+ quadrupole mass spectrometer is used for elemental analysis of environmental samples such as river and seawater and geological specimens.
The Wallace Astrophysical Observatory is a teaching and research facility run by the EAPS planetary astronomy lab. Students in the observing subjects at MIT, 12.409 "Hands-on Astronomy: Observing Stars and Planets" and 12.410 "Observational Techniques of Optical Astronomy", travel to Wallace to make observations.
The EMP facility is a part of EAPS’s Center for Geochemical Analysis. It is open to the entire MIT and WHOI (Woods Hole Oceanographic Institution) research community, with occasional use by external personnel. With its two JEOL JXA-733 Superprobes, the EMP provides a complete quantitative analysis of microscopic volumes of solid materials through x-ray emission spectrometry, and it provides high-resolution scanning electron and elemental x-ray images (also known as concentration maps). There are two types of scanning electron images: backscattered electron images, which show compositional contrast, and secondary electron images, which show enhanced surface and topographic features. In addition, scanning cathodoluminescence images, which is an image formed by light emission in response to electron interaction with the sample, can also be obtained.
Work in the Isotope Geochemistry and Geochronlogy Lab has three themes: timescale calibration, evolution of continental crust, and environmental geochemistry. The research group is directed by Professor Sam Bowring.
- Uranium-Lead: Our laboratory is centered around a VG Sector 54 mass spectrometer and a Micromass Isoprobe-T which are housed in a temperature controlled “clean room” equipped with laminar flow stations. The Sector 54 instrument is equipped with seven Faraday cups and an ion-counting Daly detector for small ion beams. The Isoprobe T is equipped with nine Faraday collectors, an ion-counting Daly, and a WARP filter. U-Pb zircon analyses are performed using a mixed 205Pb-235U-233U spike, with total procedural blanks that are routinely 0.4-1.5 picograms for lead and less than 0.1 picograms for U. Using single collector ion-counting with peak jumping, we achieve high-precision analyses of samples with as little as 5-10 picograms of radiogenic Pb; at present, our minimum sample size is blank limited.
- Samarium-Neodymium: Nd and Sm analyses are routinely done in dynamic analysis mode with external reproducibility of isotope ratios over 10 years better than 20 ppm (2 sigma). La Jolla Nd analyses over the same period yield 143Nd/144Nd = 0.511854 ± 0.000009 (2 sigma) for 144Nd = 1.5 X 10-11 amp analyses. Samarium is typically analyzed in static multicollector mode with precision better than 0.01% (2 sigma).
The EAPS neutron activation laboratory does gamma-ray spectroscopy of samples subjected to a high flux of thermal neutrons in the MIT Nuclear Reactor. Most samples are analyzed by Instrumental Neutron Activation Analysis (INAA); i.e., no chemical processing is done. This approach provides precise abundance data at the parts per million level for Na, Cs, Sc, Cr, Co, Hf, Ta, La, Ce, Nd, Sm, Eu, Tb, Yb, Lu, and Th. The important aspects of this technique are that the sample is not destroyed, and there is no contamination of the sample by impurities in chemical reagents. The gamma-ray spectroscopy is done with Ge semi-conductor detectors interfaced to multichannel analyzers, under the control of a DEC MicroVax computer using the software reduction package TEABAGS. Although a wide range of materials—from spec-pure graphite and SiO2 to blood serum and lichen—have been analyzed, most of the samples studied are powdered rocks. In addition to INAA, precise data for a wide variety of other elements, such as platinum group metals, can be obtained by utilizing chemical procedures to isolate elements or groups of elements prior to gamma-ray spectrometry.
The Noble Gas Geochronology Laboratory supports researchers from MIT and collaborating institutions with analytical facilities for 40Ar/39Ar and (U-Th)/He geochronology and thermochronology. Current research themes for MIT users range from landscape evolution in orogenic systems to high-resolution dating of volcanic sequences. The facility is under the direction of Dr. Bill Olszewski.
- 40Ar/39Ar: Currently, 40Ar/39Ar analyses are performed using a Mass Analyser Products 215-50 magnetic sector mass spectrometer fitted with both a faraday collector and an electron multiplier. Two gas extraction lines are connected to the instrument, one for samples degassed in a resistance furnace and the other for samples degassed with lasers. The furnace line is used for conventional step-heating analyses of samples and Ar diffusion studies. However, most of our focus is on laser-microprobe 40Ar/39Ar geochronology. Two laser microprobes are available for use in the facility: a 10W Ar-ion instrument used for heating and fusion of small groups of crystals, single crystals, and crystal fragments; and an ArF excimer laser used for high-spatial resolution ablation and isotopic mapping of single crystals.
The Organic Geochemistry Laboratory supports research in geobiology and biogeochemistry. There are two GS-MS systems based on an Agilent mass selective detector and a Micromass Autospec double focusing mass spectrometer. A water Q-TOF Micro LC_MS system enable analysis of intact polar lipids and pigments. Carbon, hydrogen, and nitrogen isotope analyses of bulk materials and individual organic compounds are made with a Thermo-Finnigan Delta Plus XL instrument.
ACES focuses on developing and deploying advanced computational technologies to address challenging problems of earth science. As a platform for cross-disciplinary collaboration between MIT researchers in earth science and computer science, ACES develops applications to address a wide spectrum of questions about how planetary systems work. To answer these questions, substantial computational resources must be deployed and efficiently harnessed. Participants in ACES are engaged in both the development of novel compute environments and in their application to problems in earth science.
The synoptic laboratory, sited on the 16th floor of EAPS, comprises a cluster of interconnected workstations, mass-store devices and a large hyperwall used to analyse and display synoptic data. The laboratory provides access to real-time meteorological observations, analyses and forecasts, and specialized custom diagnostics. The synoptic lab is used in both teaching and reasearch.
Situated on the 15th floor of EAPS, the recently refurbished (2006) GFD laboratory consists of several rotating fluid turntables with cameras providing a birds-eye view in the rotating frame of reference – see http://paoc.mit.edu/cmi/applications/fluidlab.htm. The camera is connected to display and analysis devices. Observations of dye and particles under motion are made using laser sheets to illuminate surfaces of interest. The lab is extensively used in undergraduate and graduate education - see here: http://paoc.mit.edu/labweb/experiments.htm.
Research in the MIT Paleomagnetism Laboratory focuses on interdisciplinary problems in planetary science, geology and geobiology. Current topics include the evolution of the Martian dynamo and climate, the nature and origin of lunar magnetism, the earliest history of Earth's magnetic field, the fossil record of magnetotactic bacteria, Neoproterozoic and Cambrian global change, and the origin of magnetization in carbonate rocks. The lab has two magnetically shielded shielded class 10,000 clean rooms which contain a variety of equipment for measuring the magnetic records and magnetic properties of natural samples. Tha lab has a variety of magnetometers including a superconducting rock magnetometer equipped with a 200-sample automated rock magnetic and degaussing system and the unique Superconducting Quantum Interference Device (SQUID) Microscope which makes high resolution (100-micron spatial resolution) magnetic field maps of thin sections.