Geomagnetic polarity reversal rate for the Phanerozoic

The recently updated Global Paleomagnetic Database provides an opportunity to construct a preliminary model of long-term magnetic polarity reversal behavior for the last 570 My. After filtering for quality, a sub-set of data from this global database is used to estimate relative reversal frequency, and the results show the expected long intervals of low reversal rate during the Cretaceous Normal and Permo-Carboniferous Reversed Superchrons. In addition to the established superchrons, these new results indicate a long period of very low reversal rate in the Ordovician, which may be a previously unidentified superchron, and an additional short period of anomalously low reversals at the Jurassic/Triassic boundary. If the Ordovician reversal rate anomaly is a single polarity superchron, it represents the third major change in reversal rate within the Phanerozoic, with approximately 200 My between the CNS, the PCRS and the new Ordovician reversed interval.

[1]  Michael W. McElhinny,et al.  Global Paleomagnetic Database Supplement number one: Update to 1992 , 1993 .

[2]  M. McElhinny,et al.  Global Paleomagnetic Data Base updated , 1993 .

[3]  J. Marcoux,et al.  Magnetostratigraphy of the Late Triassic Bolücektasi Tepe section (southwestern Turkey): implications for changes in magnetic reversal frequency , 1992 .

[4]  M. McElhinny,et al.  Global Paleomagnetic Data Base complete , 1991 .

[5]  D. Kent,et al.  Magnetostratigraphy and paleomagnetic poles from Late Triassic-earliest Jurassic strata of the Newark basin , 1991 .

[6]  Roger L. Larson,et al.  Mantle plumes control magnetic reversal frequency , 1991 .

[7]  A. Trench,et al.  Ordovician magnetostratigraphy: a correlation of global data , 1991, Journal of the Geological Society.

[8]  R. Larson.  Geological consequences of superplumes , 1991 .

[9]  R. Larson.  Latest pulse of Earth: Evidence for a mid-Cretaceous superplume , 1991 .

[10]  N. Opdyke,et al.  Magnetic polarity stratigraphy and carboniferous paleopole positions from the Joggins Section, Cumberland Structural Basin, Nova Scotia , 1991 .

[11]  M. McElhinny,et al.  Reversals of the Earth's magnetic field and temporal variations of the dynamo families , 1991 .

[12]  M. McElhinny,et al.  The Global Paleomagnetic Database , 1991 .

[13]  M. McElhinny,et al.  The Global paleomagnetic database : design, installation and use with ORACLE , 1991 .

[14]  V. Courtillot.  What caused the mass extinction? A volcanic eruption. , 1990, Scientific American.

[15]  W. B. Harland,et al.  A Geologic Time Scale 1989 , 1990 .

[16]  J. Besse,et al.  Magnetic Field Reversals, Polar Wander, and Core-Mantle Coupling , 1987, Science.

[17]  K. Mccartney,et al.  Mantle plumes and the periodicity of magnetic field reversals , 1986 .

[18]  P. L. Mcfadden,et al.  Lower mantle convection and geomagnetism , 1984 .

[19]  E. Irving,et al.  Reversals of the geomagnetic field, magnetostratigraphy, and relative magnitude of paleosecular variation in the phanerozoic , 1976 .

[20]  M. McElhinny.  Geomagnetic Reversals during the Phanerozoic , 1971, Science.

[21]  M. Steiner,et al.  Evidence for long intervals of normal polarity during the cretaceous period , 1968 .