  We present first measurements of the pseudorapidity and azimuth $(\eta,\phi)$
bin-size dependence of event-wise mean transverse momentum $<p_{t} >$
fluctuations for Au-Au collisions at $\sqrt{s_{NN}} = 200$ GeV. We invert that
dependence to obtain $p_t$ autocorrelations on differences
$(\eta_\Delta,\phi_\Delta)$ interpreted to represent velocity/temperature
distributions on ($\eta,\phi$). The general form of the autocorrelations
suggests that the basic correlation mechanism is parton fragmentation. The
autocorrelations vary strongly with collision centrality, which suggests that
fragmentation is strongly modified by a dissipative medium in the more central
Au-Au collisions relative to peripheral or p-p collisions. \\
