Sandstone Hosted Intrusions - A New Class of Short and Long-term Fluid Pathway

Dedicated - Fluids and Fluid Flow. Sandstone hosted injectites from the Colorado Plateau of SE Utah are sedimentologically different from many other described occurrences of sand injection. Whereas many large-scale sand intrusion provinces are hosted in deep marine mudstone successions, the intrusions of Kodachrome Basin State Park, Ut, are hosted in Jurassic aeolian and coastal strata. The difference in depositional setting has produced a large-scale intrusion province hosted in sandstone with evidence of a tripartite architecture and over 200 m vertical transport of clasts. These injections contain previously undescribed facies, which are described in detail and have important implications for the nature of fluid flow in sandstone hosted injectite complexes, specifically how their processes differ from those in mudstones. Evidence is provided for injections acting as long-term fluid conduits following emplacement, showing that these largely unrecognised systems may play a key role in basin-scale fluid migration.