  Let $p>3$ be a prime number and $K$ be an imaginary quadratic field where $p$
splits. Let $K_\infty$ be the $\mathbf{Z}_p^2$-extension of $K$ and let $K_n$
be a finite subextension of $K_\infty/K$. Let $E$ be an elliptic curve with
good ordinary reduction at $p$. Under some hypotheses, we show that the
Mazur-Tate element attached to $E$ over $K_n$ by S. Haran generates the Fitting
ideal of the dual Selmer group of $E$ over $K_n$.
