Cosmogenic 44Ti in meteorites – a divergence with 14C and 10Be data.

A record of 44Ti activity measured in 20 stony meteorites fallen during CE 1766–2001 was compared to six series of 44Ti activity, calculated from the data on modulation parameter Φ based on cosmogenic isotopes 14C and 10Be. It was shown that both experimental and computed records have appreciable divergences. The secular trends of many model curves are flatter than that of the measured record and the difference in amplitude of the century-scale cycle of Gleissberg is highly significant (p < 5.5 × 10−4). Possible causes of this discrepancy are discussed. The obtained results show that at present the cosmogenic isotope data likely contain mostly qualitative information about the behavior of the cosmic ray flux in the past and not always are suited for quantitative estimations. [ABSTRACT FROM AUTHOR]