Possible Proof that determinant of submatrix of Unitary matrix is alswys greater 0?

Question

Is there a method to show that $\det(R) > 0$ with $R^{M\times M}$ as a submatrix of an orthogonal matrix $Q^{N\times N}$, with $QQ^T=I_N$, $M<N$.

I would be grateful for a helpful hint.