The Middle Creek zone of the Galore Creek deposit is located at the headwaters of Galore Creek, a northerly flowing tributary of the Scud River, some 85 kilometres south-southwest of Telegraph Creek.
At least twelve alkalic porphyry copper-gold deposits are known to occur within the Galore Creek syenite complex. This complex comprises a series of Late Triassic to Early Jurassic orthoclase-porphyry syenitic bodies which have intruded coeval Upper Triassic Stuhini Group volcanic rocks and related sediments. Faults which offset and segment the intrusive rocks and a sub-horizontal fracture cleavage are the two main structural elements in the syenite complex. The complex is roughly 5 by 2.5 kilometres in area.
The deposits are hosted primarily by highly altered potassium- enriched volcanic rocks and pipe-like breccias adjacent to syenite dikes and stocks. Typically, the deposits are manto-shaped and have a north to northeast trend related to the syenite contacts and zones of structural weakness.
The syenite complex is made up of four intrusive phases that are most closely associated with the copper deposits. Six other phases are recognized but are peripheral to the Central zone deposit. The copper-bearing rocks near the syenite intrusion are extensively metasomatized, recrystallized and locally brecciated. These may include pyroclastic and intrusive breccia, trachyte, phonolite, lithic tuff, crystal tuff, pyroxene basalt, pyroxene andesite and minor sediments. These rocks have been converted to skarns and fenitic porphyroids so that original rock types are unclear. The term "hornfels" was frequently applied to these meta-volcanic rocks in the early stages of exploration.
Alteration and mineralization are contemporaneous and spatially overlap. The hydrothermal system was extensive and the resultant alteration led to the formation of large gossans. Potassic alteration consisting of potassium feldspar, titanium biotite and magnetite have converted the syenites and volcanic rocks to pink, white and orange rocks composed mostly of orthoclase. Alteration of pyroxene, hornblende and biotite to assemblages of chlorite and calcite plus/minus albite and epidote characterizes the propylitic zone, best developed in the syenitic rocks. Calc-silicate alteration consisting of abundant garnet, diopside, epidote, albite and anhydrite is an unusual feature of the complex. Garnet replaces up to 50 per cent of the metavolcanic rocks and infills breccias near the northern end of the Central zone breccia pipe but is generally absent from the other deposits. However unusual this metasomatic overprint is, the distribution of sulphides, precious metal and magnetite is considered consistent with the expected zoning pattern for alkalic porphyry deposits.
Copper-gold mineralization was discovered in 1991 at the previously unknown Middle Creek zone, located about 1 kilometre west of the Central zone (104G 090). Mineralization consists of finely disseminated bornite, chalcopyrite and magnetite, associated with pervasive fine-grained biotite and garnet in an altered, intermediate tuffaceous unit (CIM Special Volume 46).
In 2011, the Junction zone was described in a technical report (43-101) by AMEC Americas Limited on behalf of NovaGold (Galore Creek Project by AMEC, July 17, 2011) as follows:
"Limited exploration has been completed over this prospect. Middle Creek is located approximately 1 kilometre west of the Central Zone. In 1991, field mapping found mineralization reported by prospectors in the mid 1960s.
Mineralization is characterized by finely-disseminated bornite, chalcopyrite and magnetite associated with pervasive fine-grained biotite and garnet alteration, hosted in a breccia or volcaniclastic unit. Middle Creek is the most oxidized zone discovered to date on the Galore Creek property. Drilling during 2005 encountered malachite and native copper mineralization."
AMEC reports five zones as being modelled toward its 2011 Mineral Resource Estimate for the Galore Creek deposit: the Central Zone (including the Bountiful deposit), Southwest Zone, Junction/North Junction Zone, Southwest Zone, and West Fork Zone.
Refer to the Central Zone deposit (104G 090) for further details of the Galore Creek deposits. Further details of a common work history and 2011 reserves and resources are given. Details of work history on specific zones is not readily available or easily broken out from the overall Galore property body of work.