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Published on: August 2, 2021
Oxygen isotope zoning in garnet.
Science (New York, N.Y.)
|October 18, 1991
Summary
Oxygen isotope zoning in metamorphic garnets reveals fluid infiltration and dehydration reactions during metamorphism. These changes in oxygen isotope values (delta(18)O) provide insights into geological processes.
Area of Science:
- Geochemistry
- Isotope Geology
- Metamorphic Petrology
Background:
- Garnet is a key mineral in metamorphic rocks, preserving information about P-T conditions.
- Oxygen isotope analysis is a powerful tool for tracing fluid-rock interactions.
Purpose of the Study:
- To investigate oxygen isotope zoning within metamorphic garnets.
- To understand the influence of metamorphic processes on garnet geochemistry.
Main Methods:
- Stable isotope laser probe analysis of oxygen isotopes (delta(18)O).
- Examination of four garnets from Vermont and Utah.
Main Results:
- Concentric oxygen isotope zoning (delta(18)O) was observed in all examined garnets.
- Regional metamorphic garnets showed the largest variations (up to 3 per mil from core to rim).
Conclusions:
- Oxygen isotope zoning in garnets reflects changes in rock delta(18)O during growth.
- Fluid infiltration and dehydration reactions are key drivers of these isotopic variations during metamorphism.
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