Abstract

Source rocks in the Charleston-Nebo allochthon included shales of the Pinyon Peak Formation, phosphatic shales of the Deseret Limestone, the Manning Canyon shales, the Curry Peak organic siltstones, and phosphatic shales of the Meade Peak member of the Plympton Formation. Cretaceous shares are potential source rocks beneath the leading edge of the allochthon in the Strawberry Valley area. Hydrocarbons in fractures of Permian Freeman Mountain Sandstone at Daniels Summit are residues of oil migrated from onlapping Wasatch Formation.

From Nephi to Las Vegas, the source rocks along the Wasatch-Las Vegas Hingeline were the Pinyon Peak shales, the Deseret-Monte Cristo phosphatic shales, the Chainman shales and the Meade Peak phosphatic shales of the Plympton Formation. The source rocks were originally positioned for optimum migration into the Devonian through Permian reservoir rocks of the platform facies. Possibly Paleozoic migration from the Meade Peak shales formed the present tar sands of the White Rim sandstone and the Sinbad limestone.

Pre-Pakoon dolomite (Wolfcampian), pre-Black Box dolomite (Leonardian) and pre-Moenkopi (Triassic) erosion removed many source units from the platform area particularly from the Emergy High area.

Sevier thrusting separated source rocks from reservoir rocks so that migrations were probably ineffective into the platform facies after the initial thrusting. Later, the presence of a metamorphic core complex in the present Sevier desert destroyed the source rock potential.