Cosmochemistry and Geochemistry

The Geochemistry/Geochemist Group at DTM has four staff members: Conel Alexander, Rick Carlson, Larry Nittler, and Steve Shirey.  With the support of chemistry lab manager, Mary Horan, mass spec lab manager, Tim Mock, and ion probe specialist, Jianhua Wang, research projects involving the staff can range from a short, informal nature to those that are long term. Research collaborations are welcome on almost any professional level: as an intern, a pre-doctoral fellow, a post-doctoral fellow, a visiting scientist, or a Tuve fellow. Most projects are NSF or NASA funded, but with the Carnegie Institution’s high level of ongoing lab support, important scientific questions can be attacked without the proposal lead-time that NSF or NASA funding requires. The most fruitful collaborations are those that align with the interests of the staff and the type of analyses suited to our facilities (see below).

Cosmochemists address the early history of the solar system, the formation and early evolution of meteorites, and the nature of the impact cratering process on Earth. Research in geochemistry combines laboratory and field studies of modern and ancient rocks from diverse geographic areas

Cosmochemistry & Geochemistry Instrumentation

Stromboli Volcano in Italy. (Michael Acierno, DTM)


Staff Scientists

Conel M. O'D. Alexander - Cosmochemistry; isotopic chemistry and origin of interstellar grains

Richard W. Carlson - Isotope geochemistry; history and nature of chemical evolution of the Earth's crust and mantle; early history of the solar system

Larry R. Nittler - Cosmochemistry; presolar grains in meteorites; secondary ion mass spectrometry and planetary remote sensing

Steven B. Shirey - Igneous petrology; isotope geochemistry; trace element geochemistry; geochemical evolution of the Earth's crust and mantle

Technical Staff

Mary Horan - Geochemistry Laboratory Manager

Timothy Mock - Mass Spectrometry Laboratory Manager

Jianhua Wang - SIMS Lab Manager

Postdoctoral Fellows

Andrea Patzer - Ph.D. Max-Planck-Institution for Chemistry (2000)

Kei Shimizu - Ph.D. Brown University (2016)

Jonathan Tucker - Ph.D. Harvard University (2016)

Da Wang - Ph.D. washington State University, Pullman (2018)

Facilities for Research


Thermo Scientific Triton XT Thermal Ionization Mass Spectrometer (2019)

Thermo-Fisher Triton (2004)


Nu Plasma HR, Nu Plasma II, Axiom


NanoSIMS 50L, Cameca 6f with 1 Meter Magnetic Sector

Chemistry Laboratories

Multiple clean-room facility equipped for all aspects of sample preparation


JEOL 6500F

Also on campus:

JEOL JXA-8530F Automated Field Emission Electron Microprobe, JEOL 8900 electron microprobe, Zeiss Auriga FIB-SEM, FTIR, Raman Spectroscopy

Supporting Laboratories

Optical Microscopy, Microsampling, Rock Room, Machine Shop, Electronics Laboratory