U-Th-Pb geochronology has become a fundamental tool in Earth Science research, with applications that cover the span of structural geology, tectonics, stratigraphy, paleontology, petrology, and geochemistry. Although many U-Th-Pb analytical techniques and applications are well established, emerging technologies are revolutionizing the way geochronologic information can be acquired and applied. Some of the most exciting advances in the field are being driven by laser-ablation multicollector ICP mass spectrometers, which allow for rapid determination of U-Th-Pb ages with micron-scale spatial resolution. These instruments are fundamentally changing the way geochronologic information is utilized in Earth Science research.
Accelerator Mass Spectrometry Laboratory
After Willard Libby demonstrated in 1946 that the time since the death of an object could be determined by measuring its 14C activity, researchers in disciplines from Anthropology to Zoology have exploited this discovery. Among these researchers are members of the University of Arizona, Department of Geosciences, who for years
have studies the 14C content of various anthropological and geophysical specimens.
Environmental Isotope Laboratory
Faculty, staff, and students in the Environmental Isotope Laboratory employ naturally occurring stable and radioactive isotopes as well as major element compositions to hydrological and geological questions. Study areas are generally local or in nearby hydrologic basins, and problems range from locations and extent of groundwater recharge to sources of chloride in brines. Students learn techniques of sampling and analysis of waters for tritium, radiocarbon and stable isotopes, and their interpretation.
Arizona Radiogenic Helium Dating Lab
Alpha decay of uranium and thorium to helium provides a versatile radioisotopic system for geochronology and thermochronology. This technique can be used to date a variety of events, and constrain thermal histories of rocks through a range of temperatures. It is commonly used to measure the spatial and temporal patterns of erosional or tectonic exhumation, orogenic events, and landscape evolution. Work in the Arizona Radiogenic Helium Dating Lab (ARHDL, pronounced "aarrhdduhl") covers a wide range of processes in earth and planetary science, and we host a large number of visiting researchers. Much of our work comes in figuring out new and better ways to measure He ages, such as in situ methods, and novel ways to apply the system, such as in studying meteorite impacts, wildfire, detrital analysis, and shallow faulting.
Arizona Noble Gases Laboratory
ANGL provides high-precision ,40Ar/39Ar and other noble gas analyses useful for a wide range of applications in Earth and planetary science. The lab is equipped with two fully automated gas-source sector mass spectrometers, and both laser and furnace extraction systems.
Ducea Geochronology and Thermochronology Lab
We determine ages of igneous, metamorphic and sedimentary rocks using the Sm-Nd, Rb-Sr and K-Ca chronometers either by thermal ionization mass spectrometry of multicollector ICP-MS. Some of the applications use the laser ablation system attached to the ICP-MS. Our targeted applications are complementary to other techniques used in the department, such as those in the U-Pb LaserProbe, Ar-Ar or U-Th/He laboratories.
1. Garnet Sm-Nd thermochronology on high grade metamorphic rocks from arc and collisional terrains � e.g. Coast Mountains (British Columbia), western Gneiss Region (Norway), the South Carpathians (Romania), Sierra de Famatina (Argentina);
2. Rb-Sr dating of shear zones in metamorphic rocks;
3. K-Ca chronology of sedimentary rocks of Late Precambrian- Paleozoic rocks from the southwestern U.S.;