The Mariana Project is located in the Sierra Madre Occidental area of Northern Mexico. The property area is more specifically located in the Sahuaripa District, which geologically consists of Cretaceous to Tertiary sedimentary and volcanic sequences. Marine sedimentary limestones, sandstones and siltstones belonging to the Lower Cretaceous El Palmar Formation are stratigraphically followed by Upper Cretaceous agglomerates, sandstones, and andesite tuffs. These El Palmar Formation sediments have been structurally sheared and thrust-faulted over the more recent sediments and andesite tuffs.
Overlaying the marine sediments and tuffs are a series of volcano-sedimentary rocks and andesitic flows. Regionally, this stratigraphy is known as the “Lower Volcanic Sequence”. Upper Cretaceous to Lower Tertiary granodiorite and andesite porphyries intrude these earlier marine sediment and volcano-sedimentary sequences. A Tertiary sequence of andesite-basalt flows and rhyolite tuffs known as the “Upper Volcanic Sequence” (likely post-mineral) overlays this stratigraphy.
Regionally, these units, particularly the interface between the Lower and Upper Volcanic Sequences, host several significant gold and silver deposits including the Mulatos, Dolores and La India mines amongst others.