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The composition of Permian seawater
J Horita1, T J Friedman, B Lazar
1Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138.
Geochimica Et Cosmochimica Acta
|January 1, 1991
Summary
Chemical analysis of ancient brine inclusions reveals Permian seawater composition was remarkably similar to modern seawater, providing key insights into marine geochemistry.
Area of Science:
- Geochemistry
- Marine Geology
- Paleoceanography
Background:
- Marine halite preserves ancient fluid inclusions, offering a window into past ocean chemistry.
- Understanding Permian seawater composition is crucial for reconstructing Earth's climate and geological history.
Purpose of the Study:
- To determine the chemical composition of Permian seawater using brine inclusions from halite.
- To compare Permian seawater chemistry with that of modern oceans.
Main Methods:
- Extraction and chemical analysis of brine inclusions from halite samples.
- Geochemical modeling to reconstruct original seawater ratios.
Main Results:
- Permian brine inclusions (Na-K-Mg-Cl-SO4 type) resemble evaporated modern seawater.
- Key ionic ratios (e.g., Cl-/Br-, Mg2+/Br-) indicate similarities to modern seawater, with minor differences attributed to mineral precipitation.
- Constrained chemical composition of Permian seawater, showing close resemblance to present-day values.
Conclusions:
- Permian seawater chemistry was surprisingly similar to modern seawater.
- Mineral precipitation processes (dolomite/magnesite) influenced the measured ratios in some inclusions.
- The study provides a detailed chemical profile of Permian seawater.