Detailed Instructions: In this task, we ask you to elaborate the sentence without changing its general meaning. You can do so by explaining further the input sentence, using more precise wording, adding qualifiers and auxiliary information etc.
Problem:Volcanic ash ( tephra ) has a geochemical fingerprint .
Solution:
Tephrochronology is a method for geochemical correlation of unknown volcanic ash ( tephra ) to geochemically fingerprinted , dated tephra .