Geotechtonic is still used - but really. It's archaic. The English has settled on geotectonic.
By the way, if 'tectonic' comes from the greek tektonikos, the spelling 'techtonic' is not only archaic but wrong (no chi in there, but a kappa). Those whom the Gods wish to destroy They first make mad. -- Euripides
Yup! It's ..........
<wait for it!>
Gin and Techtonic!
rimshot