The melting of a horizontal ice plate from above into a calcium chloride aqueous solution in a rectangular cavity is considered numerically and experimentally. The ice plate melts spontaneously with decreasing temperature at the melting front, even when there exists no initial temperature difference between ice and liquid. Visual observations in the liquid reveal a complicated and random natural convection mainly dominated by the concentration gradient which appears near the melting front. A very coarse and curious surface of the melting front is seen after the melting experiment, that is considered to promote the ice melting. The two-dimensional numerical model proposed in the present study predicts approximately the melting rate. (C) 2000 Elsevier Science Ltd. All rights reserved.