  Non-statistical event-by-event mean-pt fluctuations in Au + Au collisions at
sqrt(s_NN) = 130 and 200 GeV are analyzed in AMPT with string-melting, and the
results are compared with STAR data. The analysis suggests that in-medium
elastic parton scattering may contribute greatly to the mean-p_t fluctuations
in relativistic heavy-ion collisions. Furthermore, it is demonstrated that
non-statistical event-by-event mean-pt fluctuations can be used to probe the
initial partonic dynamics in these collisions. The comparison shows that with
an in-medium elastic parton scattering cross section sigma_p=10 mb, AMPT with
string-melting can well reproduce sqrt(s_NN) = 130 GeV data on the centrality
dependence of non-statistical event-by-event mean-pt fluctuations. The
comparison also shows that the fluctuation data for sqrt(s_NN) = 200 GeV Au +
Au collisions can be well reproduced with sigma_p between 6 and 10 mb.
