Quantitative Test for Eustatic Events of 2 - 6 M.Y. Durationin Early Paleozoic Strata of North America
{'Code': '06030101', 'Directorate': {'LongName': 'Directorate For Geosciences'}, 'Division': {'LongName': 'Division Of Earth Sciences'}}
{'SignBlockName': 'John A. Maccini'}
We have completed the first phase of developing a new, quantitative method for analyzing a complex record of cyclicity beginning with the Cambrian strata of North America. So far we have found two orders of cycles, one consisting of a single long- term cycle with a wave length of about 70 m.y. and the other consisting of repeating short-term cycles with wavelengths of 2 to 6 m.y. The pattern cyclicity has been found to occur consistently within the ancient passive margins of North America. The form of this complex signal strongly resembles the form of the controversial eustatic sea level curve for the Mesozoic and Tertiary that has been constructed using seismic stratigraphic methods along the submerged margins of the continents. A eustatic mechanism is also a viable explanation for the Cambrian cyclicity, and, if correct, is evidence that short-term oscillations of sea level have been a dominant factor in the evolution of the stratigraphic record for much, if not all, of the earth's history. A tectonic mechanism cannot be ruled out, however. In addition to the question of the origin of the cycles, the results of our research have raised the possibility that the period of the cycles is not random, but further investigation of this problem is hampered by the lack of a reliable time scale. Finally, since our analyses have been confined to strata that were deposited mainly within a carbonate platform, we cannot evaluate the degree to which our new procedures have general applicability to the stratigraphic record. We will conduct a two-year program of research to address the questions that have been raised by the results of our previous work. We will to measure sections in key localities within the North American craton where it should be possible to both test the eustatic versus tectonic origin of the cycles and to assess the validity of our methodology in different depositional environments.
[{'FirstName': 'Michelle', 'LastName': 'Kominz', 'EmailAddress': 'michelle.kominz@wmich.edu', 'StartDate': '03/01/1989', 'EndDate': None, 'RoleCode': 'Co-Principal Investigator'}, {'FirstName': 'Gerard', 'LastName': 'Bond', 'EmailAddress': 'gcb@lamont.ldeo.columbia.edu', 'StartDate': '03/01/1989', 'EndDate': None, 'RoleCode': 'Principal Investigator'}]
{'Name': 'Columbia University Lamont Doherty Earth Observatory', 'CityName': 'Palisades', 'ZipCode': '10964', 'PhoneNumber': '9143592900', 'StreetAddress': 'Rt 9W', 'CountryName': 'United States', 'StateName': 'New York', 'StateCode': 'NY'}
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