title: Terminal cretaceous environmental events.
abstract: The geologic record of terminal Cretaceous environmental events indicates that iridium and other associated elements were not deposited instantaneously but during a time interval spanning some 10,000 to 100,000 years. The available geologic evidence favors a mantle rather than meteoritic origin for these elements. These results are in accord with the scenario of a series of intense eruptive volcanic events occurring during a relatively short geologic time interval and not with the scenario of a single large asteroid impact event.
authors.forename: C B
authors.initials: CB
authors.lastname: Officer
authors.forename: C L
authors.initials: CL
authors.lastname: Drake