Given that the d180 of marine carbonate changes through geologic time, if we know the composition of open marine carbonate (for a specific time period), what would you expect the d180 value to be of carbonate formed in a restricted hypersaline environment? a. enriched (more positive) d180 b. more negative d13C matched with a more negative d180
c. little difference because it still forms from marine water d. depleted (more negative) d180