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Record Details

Record 50 of 6195
Geologic periodicities and the Galaxy
Author and Affiliation:
Rampino, Michael R.(New York University, NY, United States)
Stothers, Richard B.(NASA Goddard Institute for Space Studies, New York, NY, United States)
Abstract: New geologic and astronomical developments are reviewed that have recently led to the proposal of various Galactic theories to explain the temporal pattern of impact craters on earth. Linear and harmonic time series analyses have revealed that two dominant periodicities about equal to 33 + or - 3 Myr and 260 + or - 25 Myr underlie the geologic record of terrestrial impact cratering and global tectonic phenomena. It is argued that purely terrestrial mechanisms cannot account for the cratering cycles as being preservational artifacts; cratering rather appears to influence tectonism, possibly through perturbations of mantle convection. Galactic models proposed to explain the two long-term periodicities are reviewed critically. The most likely explanation for the 33 Myr cycle involves the comparatively stable half period of vertical oscillation of the solar system about the Galactic plane. The 260 Myr cycle may be related to rare encounters with Galactic spiral arms during the revolution of the solar system around the Galactic center.
Publication Date: Jan 01, 1986
Document ID:
19870046841
(Acquired Nov 28, 1995)
Accession Number: 87A34115
Subject Category: ASTROPHYSICS
Document Type: Conference Proceedings
Publication Information: (SEE A87-34101)
Publisher Information: United States
Contract/Grant/Task Num: NASA TASK III; NCC5-16
Financial Sponsor: NASA; United States
Organization Source: New York Univ.; New York, NY, United States
NASA Goddard Inst. for Space Studies; New York, NY, United States
Description: 19p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: ASTRONOMICAL MODELS; COMETS; GEOCHRONOLOGY; ORBIT PERTURBATION; PERIODIC VARIATIONS; EARTH MANTLE; EXTINCTION; PLANETARY CRATERS; SOLAR OSCILLATIONS; TECTONICS; TIME SERIES ANALYSIS
Imprint And Other Notes: IN: The galaxy and the solar system (A87-34101 14-90). Tucson, AZ, University of Arizona Press, 1986, p. 241-259.
Availability Source: Other Sources
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