Light Stable Isotope Geochemistry Applied to Magmatic and Surficial Environments

January 15th to 16th 2019

Urs Schaltegger

Prof. Ilya Bindeman, University of Oregon, USA

The 2-day short course will cover the topics of low and high temperature stable isotope geochemistry with the following format: 2 h each day of advanced introductory lecture, a mid-day short exercise, a lecture on an advanced topic, and a research talk at the end of the day that could be open to other members of the Department.

The low-T stable isotope topic will include traditional (mass-dependent), mass independent O, C, S, H isotope geochemistry of sedimentary record pertinent to: Great oxidation event, maturation of the crust, Snowball earth glaciations, evolution of the chemistry of the oceans, and isotopic box modelling of fluxes affecting lithosphere, hydrosphere, atmosphere and biosphere and related controversies currently discussed in papers and conferences. Novel techniques such as clumped isotope methods will also be discussed. The research lecture may cover the evolution of the continental crust as provided by the technique of triple oxygen isotopes.

The high-T isotope geochemistry topic will deal with magma genesis in the crust and the mantle as viewed from a stable isotopic perspective. The course will touch on hydrothermal processes and magmatic hydrothermal transitions. It will employ recent topics of stable and radiogenic isotope geochemistry of zircon, and its use to unravel magma genesis. Precise triple oxygen isotopic evolution of hydrothermal rocks and water-rock interaction will be discussed. The research lecture may include the discussion of the magmatic evolution of hot spot volcanoes, including Yellowstone.

Day 1, January 15, 2019

09:15 room 605

Part 1 (1 h lecture) Introduction, some history and overview of current applications with emphasis on high-T and low-T geochemistry.

Definitions, Isotope fractionation, first principles, methods to determine or calculate, calculation of vibrational frequencies, simple thermodynamics, stable isotope thermometry. Triple oxygen isotope fractionation, clumped isotopes.  

Part 2 Stable Isotope Methods. Stable isotope mass spectrometry, historical aspects, new methods, lasers, SIMS, perks of isotope analysis

Part 3. Stable isotope hydrology, kinetic isotope fractionation, evaporation-precipitation, water isotopes in precipitation, meteoric water lines (δD and δ¹⁷O-δ¹⁸O), meteoric water cycle during glacial-interglacial, Snowball earth

Exercise: Calculation of stable isotope fractionation  

Exercise:  Stable isotope in waters and water-rock interaction

16:15 Public Research Lecture: 

Triple oxygen isotope in modern clays and shales through time: aspects of emergence of subaerial land 2.5Ga in the context of Snowball earth glaciation and the Great Oxidation Event

Day 2, January 16, 2019

09:15 room 605

Part 5 Brief overview of major stable isotopic systems (oxygen, hydrogen, carbon, sulfur) with emphasis on high-T stable isotopic applications, reservoir diagrams, processes that control isotope redistributions, main areas of applications

Exercise, TBA

Part 6 Oxygen isotopes in igneous rocks. Isotope fractionations between minerals and melts, low-, high-, and normal 18O magmas, mantle and crustal magmas. Using oxygen and hydrogen isotopes to constrain magma genesis, assimilation, sources and mechanisms of igneous rocks. Zircons and its O and Hf isotopes. Oxygen isotopic heterogeneity of igneous rocks and petrogenesis. Case studies from Iceland, Yellowstone, Western USA, Kamchatka.

Part 7 Mass independent isotope fractionation with emphasis on oxygen and sulfur cycle. Archean vs modern. Volcanic eruption influence on ozone layer. 

16:15 Public Research Lecture: 

Oxygen isotopic heterogeneity of zircons in igneous rocks: Modeling of the growth and dissolution of zircons in igneous rocks 

Genève

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