Open AccessGeomagnetic field intensity recorded after impact in the Ries meteorite crater, Germany
Author(s) -
Koch Stephan A.,
Gilder Stuart A.,
Pohl Jean,
Trepmann Claudia
Publication year - 2012
Publication title -
geophysical journal international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0956-540X
DOI - 10.1111/j.1365-246x.2012.05399.x
Subject(s) - meteorite , geology , impact crater , earth's magnetic field , dynamo , dynamo theory , secular variation , paleomagnetism , lithology , geophysics , paleontology , astrobiology , magnetic field , physics , quantum mechanics
SUMMARY We carried out palaeointensity experiments on 45 samples collected throughout the ca. 15 Ma Ries crater (Germany) to test whether meteorite impacts can influence the geodynamo. A Thellier–Thellier procedure with alteration, tail and additivity checks yields a weighted average palaeointensity of 19.1 ± 1.1 μT from 15 samples that pass stringent data selection criteria. The corresponding virtual dipole moment of 3.2 ± 0.2 × 10 22 Am 2 is relatively low, but indistinguishable from the global palaeointensity database between 20 and 10 Ma. Our results suggest that either the energy released during the Ries meteorite impact event was too low to affect the geodynamo, the Ries impact lithologies cooled too fast to record any effect, or the time averaged by the impact lithologies was long enough to record secular variation, but that the geodynamo was remarkably stable over that time.