Accretion Rates of Meteorites and Cosmic Dust in the Early Ordovician
Birger Schmitz,
*
Bernhard Peucker-Ehrenbrink,
Maurits Lindström,
Mario Tassinari
Abundant fossil meteorites in marine, condensed Lower Ordovician
limestones from Kinnekulle, Sweden, indicate that accretion rates of
meteorites were one to two orders of magnitude higher during an
interval of the Early Ordovician than at present. Osmium isotope and
iridium analyses of whole-rock limestone indicate a coeval enhancement
of one order of magnitude in the influx rate of cosmic dust. Enhanced
accretion of cosmic matter may be related to the disruption of the L
chondrite parent body around 500 million years ago.
B. Schmitz, Department of Marine Geology, Earth Sciences Centre,
University of Göteborg, S-413 81 Göteborg, Sweden.
B. Peucker-Ehrenbrink, Department of Marine Chemistry and Geochemistry,
Woods Hole Oceanographic Institution (WHOI), Woods Hole, MA
02543, USA.
M. Lindström, Department of Geology and Geochemistry,
University of Stockholm, S-106 91 Stockholm, Sweden.
M. Tassinari, Paleo Geology Center, Fabriksgatan 4, S-531 30 Lidköping, Sweden.
*
To whom correspondence should be addressed.
