As respects instruments executed prior to May 17, 1974, which convey title to real property or an interest therein, it shall be presumed that reference to minerals or mineral rights does not include geothermal resources unless geothermal resources are specifically mentioned. As respects such instruments executed on and after May 17, 1974, reference to minerals or mineral rights shall not include geothermal resources unless specifically mentioned.L. 74: Entire section added, p. 316, § 8, effective May 17.