Researchers in the Geochemistry Division seek to understand Earth’s environments by studying its history—and the processes, past and present, that have governed these environments.

Using advanced chemical and isotope analyses, Division scientists study samples of air, water, biological remains, rocks and meteorites in order to elucidate a broad range of scientific issues. Research topics range from the particulate and chemical pollutants emitted by the collapse of the World Trade Center towers on September 11, 2001, to the climate changes of the ice ages, which began some 2.6 million years ago, to the fundamental chemical processes involved in the differentiation and formation of Earth’s mantle and core.

View of the Lake Pukaki basin

View of the Lake Pukaki basin with nearly 30 different lateral and terminal moraine ridges visible around the lake. Credit: Joerg Schaefer

Observatory geochemists have also contributed greatly to our understanding of the socioeconomic issues associated with environmental changes, ranging from contaminated groundwater to the accumulation of industrial carbon dioxide (CO2) in the atmosphere, which may ultimately be seen as responsible for present-day global warming.

Some of the principal research themes in the Division include:

  • Solid-earth dynamics, including the exchange of material between Earth’s core, mantle and crust.
  • Structure and composition of Earth’s lower crust and upper mantle, with a focus on melt transport in the upper mantle, accretion of igneous lower crust at spreading ridges and arcs and the hydration and carbonation of mantlederived material that has been tectonically exposed at Earth’s surface.
  • The formation of Earth and its moon, and the transformations that occurred during the earliest phases of their histories.
  • The oceans’ role in climate, tracing ocean currents that transport heat around the globe and their variability through time, and investigating ocean processes that regulate the concentration of carbon dioxide in the atmosphere, from microscale physics at the air-sea interface to the global-scale meridional overturning ocean circulation.
  • Causes and consequences of climate change over longer timescales, ranging from variability over many thousands of years paced by subtle changes in Earth’s orbit to abrupt changes, sometimes within the span of a human lifetime, forced by as-yet unidentified mechanisms internal to Earth’s climate system.
  • Sources and fates of contaminants in the environment, transported both in air and water, with an emphasis on the New York metropolitan region and the Hudson River, but with projects extending worldwide.