Using restored cross sections to evaluate magma emplacement, White Horse Mountains, Eastern Nevada, U.S.A.

Eight serial geologic cross sections were constructed and evaluated to place geometric constraints on the shape and growth of the White Horse intrusion. Based on line-length restoration of serial cross sections oriented perpendicular to the pluton contact, the aureole was shortened approximately 54% during emplacement. Extrapolating this shortening value over the exposed area of the pluton indicates that approximately 48% of the exposed pluton area may be accounted for by the restoration. Therefore, host rocks must have been displaced out of the map plane and likely downward based on geometrical constraints provided by the cross sections. The preferred emplacement model requires in-situ chamber dilation accommodated by ductile deflection of host rocks followed by fracturing and removal of the aureole rocks via cauldron subsidence and/or stoping.