The Tree River property is at the north end of the Anialik Greenstone Belt and is underlain by mafic volcanic rocks overlain by clastic marine sediments, subsequently metamorphosed to greenschist facies. The sedimentary rocks are dated at between 2940 and 2700 Ma based on detrital zircons. A monomictic, clast-supported quartz pebble conglomerate (QPC) from 15 to 20 metres thick, lies approximately 80 m stratigraphically up-section from the volcanic / sedimentary contact. This laterally extensive unit has been traced for kilometres and is particularly enriched in gold, with background values in excess of 100 ppb Au, numerous grab samples in excess of 1 g/t Au and local occurrences of high grade gold. The most significant high-grade showing is in the eastern portion of the property where, in addition to high grade grab samples, a channel sample returned 0.35 m @ 63.15 g/t Au.
The QPC contains abundant pyrite within the matrix, carrying 1-2% in background and up to 25% in localized pods. Arsenopyrite, stibnite and sphalerite together with a green mica identified as fuchsite also occur in the matrix. The pyrite is detrital with grains described as rounded to "muffin-shaped". In addition, the matrix contains up to 5% carbonaceous material in layers parallel to bedding.