The polyphase morphogenesis of the Lick Creek Cave, Cascade County, Montana, United States of America

The Lick Creek Cave, Cascade County, Montana, U.S.A. is the result of at least three phases of morphogenesis in Madison Group carbonates since the regression of the Madison Sea (mid to late Meramecian). Room and conduit morphologies, breccia and speleothem lithologies, and sample microfabrics depict variably altered sediments from four cave development zones, possibly related to meteoric diagenesis in the Late Mississippian, meteoric and hydrothermal alteration shortly after regional uplift in the Eocene, and recent meteoric alteration. delta18O/delta13C Stable isotope geochemistry of breccia and speleothem samples suggests the recent high latitude/alpine meteoric overprint is strong. All samples are more depleted with respect to 18O than that expected for Mississippian seawater, the most depleted from recent speleothemic calcites. Recent calcites display signatures which are strongly associated with a C4 photosynthetic pathway dominated alpine vegetative regime, which became globally expansive a maximum of ∼7.3 to 6.7 Million years ago.