Radiogenic Isotope Geochemistry and Geochronology - Einzelansicht

Radiogenic isotopes are important geochemical tools. The decay of a radioactive isotope eventually produces a stable (radiogenic) isotope. The process changes the isotopic composition of elements with one or several radiogenic isotopes. This change in isotopic composition can be used in two ways: (i) The concentration ratios of the produced daughter isotope to the present parent isotope can be used to determine the age of minerals and indirectly of geological processes. Systems suitable for the dating of geologically old magmatic and metamorphic rocks include among others the parent-daughter pairs of 40K-40Ar, 87Rb-87Sr, 147Sm-144Nd, and 238U-206Pb. (ii) The isotopic composition of elements with radiogenic isotopes changes through time. Because different geochemical reservoirs have contrasting parent-to-daughter ratios, they will with time develop different isotopic compositions, which in turn can be used to fingerprint the sources of rocks or to quantify contributions from different reservoirs by mass balance.

The class is presenting the most commonly used systems for isotopic dating and provides examples on the use of radiogenic isotopes as geochemical tracers. There will be reading assignments and short presentations by students in each following part:

- Rb-Sr, Sm-Nd, Lu-Hf, Re-Os and U-Pb systems, by apl. Prof. Dr. Rolf Romer

- K-Ar system and Ar/Ar dating, noble gas isotopes, by Dr. Masafumi Sudo

We start the first lecture (90 minutes) from 16:15 on the October 15th at room 2.07 of House 27.