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Our
History
The Environmental Tracer
Group evolved during the past decade around both methodology developments
and scientific programs. Originally, starting in 1989, the focus of
the group was more or less entirely on building the LDEO Noble Gas Laboratory.
Emphasis was on terrestrial applications of noble gas studies to a broad
spectrum of scientific questions and applications. This effort resulted
in the creation of a facility with four modern, all-metal noble gas
mass spectrometers described under instruments.
The scientific problems studied by noble gases always required inclusion
of other tracers such as carbon and oxygen isotopes, or chemical compounds
such as CFC's and SF6. Whereas many of these measurements
were performed in cooperation with other groups, we established significant
measurement capacity in the area of gas chromatography, specifically
for CFC's and SF6. Presently, we are adding GC/MS capability
to this spectrum of analytical capabilities.
Our
Facilities
Our analytical facilities
include four mass spectrometric systems. Two of these systems are fully
automated for large throughput of high-precision tritium and He isotope
measurements. The third, semi-automated system is used as a multi-purpose
noble gas machine. It is used for measurements of noble gases in groundwater
and in rocks (He, Ne, Ar, Kr, and Xe). This system is equipped with
two inlet systems: one for water samples and one for rocks (crushers
plus high-temperature furnace). A fourth mass spectrometric system for
Ar/Ar dating is presently being tested for fully automated measurements.
In addition to the
mass spectrometric systems, we also have three gas chromatographic systems.
These gas chromatographic system are equipped with electron capture
detectors and are used for measurements of deliberately-injected SF6,
environmental levels of SF6 in groundwater, and CFC's and
SF6 in the atmosphere. Details of the individual analytical
systems are listed under instruments.
Our
Projects
Members
of our group work on a variety of projects including studies of water
movement in natural systems (ocean, groundwater), reconstruction of
continental paleotemperature records using aquifers as archives, gas
exchange between the atmosphere and natural water bodies, and cosmogenic
3He in sediments. For more details, see projects.
ETG
In the News
- It
rained gobs at Biosphere 2 (Arizona Star, March 19, 2002)
- Scientists
gauge effect of river spill (Bergen Record, August 2, 2001)
- Navy
sub mapping Arctic Ocean seafloor (CNN, July 1, 1998)
- Lamont-Doherty
Scientists Launch a New Spectrometer for the Study of Noble Gases (Columbia
Record, February 20, 1998)
- Keck
Helps Launch a Noble (Gas) Lab (Earth Matters, Spring 1998)
- Study
Finds the Tropics Can Cool (Columbia Record, September 15, 1995)
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