The three main methods used to date sedimentary rocks ...

Summary 1
• Lithostratigraphy:
- the basis for most geological maps
- leads to plethora of names
- relationships of units to each other is commonly unclear
- provides no insights as to the origins of the deposits
• Biostratigraphy
- the method of determining relative age by the succession of fossils
- potential problems: biogeography, incomplete sampling
• Allostratigraphy:
- requires the recognition and correlation of
unconformity/disconformity surfaces
- can potentially provide correlations over very wide areas
• Sequence stratigraphy:
- the “genetic” version of allostratigraphy
(to be covered in GLG 430)