Radiogenic Isotope Geochemistry

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Radiogenic Isotope Geochemistry

• And Its Importance To Geologic History

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Isotopes
Atoms which differ only in the number of
neutrons present in the nucleus.
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Radioactive Decay Alpha

• Loss of alpha particle from the nucleus
• Alpha particle includes 2 protons, 2 neutrons
• Atomic number decreases by 2, mass decreases by 4

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Radioactive Decay Beta

• Loss of an electron from a neutron, not from
  outer most
• energy level
• Atomic number increases by 1

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Radioactive Decay Electron Capture

• Proton captures an electron from outside source
• Atomic number decreases by 1
• Example Potassium-Argon Decay

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Bohrs Model of the Atom

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Isotope Half-Life
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Mass Spectrometer
The Baylor Brooks Laboratory San Diego State
University
VG Sector 54, seven-collector thermal ionization
mass spectrometer
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How It Works The Basics
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A more advanced look
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DiffusionHow and Why?

• Inability to maintain structure
• Melting
• Metamorphism
• Weathering and Alteration
• Recrystallization
• Reheating
• Physical Damage

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Importance of a Closed System
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Closed System Mineral Examples
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Closed System Mineral Examples
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Yukon-Tanana
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Portage, Alaska
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Polychrome Mountain, Denali, Alaska
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Polychrome Mountain, Denali, Alaska
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Polychrome Mountain, Denali, Alaska
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Denali, Alaska