  We study string loop corrections to the gravity kinetic terms in type IIB
compactifications on Calabi-Yau threefolds or their orbifold limits, in the
presence of $D7$-branes and orientifold planes. We show that they exhibit in
general a logarithmic behaviour in the large volume limit transverse to the
$D7$-branes, induced by a localised four-dimensional Einstein-Hilbert action
that appears at a lower order in the closed string sector, found in the past.
Here, we compute the coefficient of the logarithmic corrections and use them to
provide an explicit realisation of a mechanism for K\"ahler moduli
stabilisation that we have proposed recently, which does not rely on
non-perturbative effects and lead to de Sitter vacua. Our result avoids no-go
theorems of perturbative stabilisation due to runaway potentials, in a way
similar to the Coleman-Weinberg mechanism, and provides a counter example to
one of the swampland conjectures concerning de Sitter vacua in quantum gravity,
once string loop effects are taken into account; it thus paves the way for
embedding the Standard Model of particle physics and cosmology in string
theory.
