Because climate is a global phenomenon, the various lithofacies and [[Fossil assemblage|biofacies]] that reflect climate in the time interval of interest must be correlated accurately. Climates may change abruptly, and [[Biostratigraphic correlation and age determination|biostratigraphy]] provides the only practical means to demonstrate the contemporaneity, or lack of it, of contrasting climates.
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Because climate is a global phenomenon, the various [[lithofacies]] and [[Fossil assemblage|biofacies]] that reflect climate in the time interval of interest must be correlated accurately. Climates may change abruptly, and [[Biostratigraphic correlation and age determination|biostratigraphy]] provides the only practical means to demonstrate the contemporaneity, or lack of it, of contrasting climates.