Rare Earth Elements in Geology

This lesson covers rare earth elements, focusing on lanthanides and actinides. It explains the lanthanide contraction and Otto Harkins rule, and how these elements are used in geology to evaluate processes like mantle melting. The video also discusses normalization and spider diagrams for presenting data, and how to interpret rare earth element patterns. Finally, it explores europium and cerium anomalies, highlighting their significance in geochemical analysis.

Which group of rare earth elements is most commonly studied in geology?

• Actinides

• Lanthanides

• Transition metals

• Alkali metals

What is the lanthanide contraction?

• Increase in atomic size with atomic number

• Decrease in ionic radius with atomic number

• Increase in ionic radius with atomic number

• Decrease in atomic size with atomic number

According to the Otto Harkins rule, elements with which type of atomic number are more abundant?

• Composite atomic numbers

• Prime atomic numbers

• Even atomic numbers

• Odd atomic numbers

What is the purpose of using spider diagrams in geology?

• To analyze mineral hardness

• To measure seismic activity

• To compare rare earth element concentrations

• To map geological formations

Why do geologists normalize rare earth element concentrations?

• To compare with a known reservoir

• To increase the concentration values

• To decrease the concentration values

• To eliminate all anomalies

What is a common reservoir used for normalization in geology?

• Upper crust

• Chondrites

• Ocean water

• Atmosphere

What happens to europium in reduced environments?

• It becomes trivalent

• It becomes divalent

• It remains unchanged

• It becomes tetravalent

In oxidized environments, cerium can become:

• Monovalent

• Tetravalent

• Trivalent

• Divalent

What does a negative europium anomaly indicate?

• Europium has been added to the sample

• Europium has been removed from the sample

• No change in europium concentration

• Increase in europium concentration

Which elements are used to calculate cerium anomalies?

• Calcium and Magnesium

• Lanthanum and Praseodymium

• Samarium and Gadolinium

• Iron and Nickel