2009 Portland GSA Annual Meeting (18-21 October 2009)
Paper No. 50-1
Presentation Time: 1:30 PM-1:45 PM


KOWALEWSKI, Michal1, ALROY, John2, BOYER, Alison G.3, BROWN, James H.4, FINNEGAN, Seth5, KRAUSE, Richard A. Jr6, LYONS, S. Kathleen7, MCCLAIN, Craig R.8, MCSHEA, Dan9, NOVACK-GOTTSHALL, Philip M.10, PAYNE, Jonathan L.11, SMITH, Felisa4, SPAETH, Paula A.8, STEMPIEN, Jennifer A.12, and WANG, Steve C.13, (1) Florida Museum of Natural History, University of Florida, 1659 Museum Road, PO Box 117800, Gainesville, FL 32611, kowalewski@ufl.edu, (2) Department of Biological Sciences, Macquarie University, Room E8A 320, Sydney, 2109, Australia, (3) Ecology, Behavior and Evolution Section, Univ. California- San Diego, 9500 Gilman Dr, MC 0116, La Jolla, CA 92093, (4) Biology, University of New Mexico, MSC 03-2020, 1 University of New Mexico, Albuquerque, NM 87131, (5) Geological and Environmental Sciences, Stanford University, 450 Serra Mall, Building 320, Stanford, CA 94305, (6) Department of Geology & Geophysics, Yale University, New Haven, CT 06520, (7) Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, P.O. Box 37012, Washington, DC 20013, (8) National Evolutionary Synthesis Center, 2024 W. Main Street, Suite A200, Durham, NC 27705, (9) Department of Biology, Duke University, Durham, NC 27708, (10) Department of Biological Sciences, Benedictine University, Lisle, IL 60532, (11) Dept. of Geological & Environmental Sciences, Stanford University, 450 Serra Mall, Building 320, Stanford, CA 94305, (12) Department of Geological Sciences, University of Colorado at Boulder, 2200 Colorado Ave, Boulder, CO 80309, (13) Mathematics and Statistics, Swarthmore College, 500 College Ave, Swarthmore, PA 19081

The term “Geozoic” is proposed as a new informal geochronologic/chronostratigraphic unit defined by the time interval of existence of life on our planet. The lower boundary of this unit is defined biostratigraphically by the oldest direct evidence for presence of life on Earth. The upper boundary is the present time (life is still around on our planet). The term Geozoic is chronostratigraphically synonymous with the expression “the entire fossil record” and geochronologically synonymous with the expression “the entire documented history of life.” Geozoic encompasses multiple eons (i.e., most of the Archean, the entire Proterozoic, and all of the Phanerozoic) and merits a geochronological rank of informal supereon. The time from the formation of the Earth until the oldest direct evidence of life (i.e., the Hadean and the early Archean) can be referred to as “Pregeozoic,” thus dividing the earth’s history into two informal supereons. Geozoic, defined by one of the most important events in the history of our planet (i.e., the appearance of life), reflects a more fundamental subdivision than the currently accepted and widely used informal supereons that split the Earth’s history into two time intervals of “non-visible” (Precambrian/Cryptozoic) and “visible” (Phanerozoic) life. The terms “Geozoic” and “Pregeozoic” are convenient because they represent an expedient way to refer to the geological processes, patterns, and records that correspond to the interval of time during which life must have existed on our planet. Because the origin of life must predate the oldest fossilized records of life, the Geozoic supereon represents the most conservative estimate of the biosphere’s existence time.

2009 Portland GSA Annual Meeting (18-21 October 2009)
General Information for this Meeting
Session No. 50
Paleontology: Extinction & Turnover
Oregon Convention Center: Portland Ballroom 256
1:30 PM-5:30 PM, Sunday, 18 October 2009

Geological Society of America Abstracts with Programs, Vol. 41, No. 7, p. 158

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