Annuncio • Jun 12
Northern Lights Resources Corp Reports Results of 3D Inversion Modelling of Aeromagnetic Survey Data At Mt Horetzky Copper Porphyry Intrusion
Northern Lights Resources Corp. has reported results of 3D inversion modelling of aeromagnetic survey data, from the Mt Horetzky copper porphyry intrusion, located within the Company’s Horetzky Copper Project in British Columbia’s Babine Porphyry Belt. The 3D inversion provides a model of the deep structure of the Mt. Horetzky intrusive complex. When integrated with historical surface geochemistry, radiometrics and digital elevation model data, the results support the Company's porphyry-style copper exploration model and provide additional context for target refinement at Horetzky. The Horetzky Copper Project is located in north-central BC in the Babine Porphyry Belt. Eocene (49 to 53 ma) biotite-feldspar intrusive stocks and dykes intrude Triassic to Early Cretaceous volcanic and sedimentary host rocks. Exploration is focussed on porphyry-style Cu (+Mo, Au-Ag) mineralization. The project comprises 11 mineral claims for a total area of 5,057.29 hectares, over which Northern Lights has an exclusive earn-in option. The Babine Porphyry Belt hosted two past producing copper mines (Bell and Granisle), and numerous significant occurrences at Morrison, Hearne Hill, and Duke. The Horetzky project has characteristics of the classical porphyry style deposit model, exemplified by the neighbouring NAK deposit operated by American Eagle Gold. Horetzky was originally explored in the early 1900’s for silver associated with base metal veins. Exploration for porphyry-style mineralization restarted in the 1960’s with the discovery of the Bell and Granisle deposits. More recently, various operators have completed soil and rock sampling, ground and airborne geophysics, and a limited diamond drill programme of 8 shallow holes by Hecla Mining in 1973. Analytical results of drill core indicated widespread Cu mineralization spatially coincident with the core porphyry intrusion. The structural composition of the Babine Porphyry Belt likely reflects four significant tectonic events, including folding and uplift in response to the Stikinia-Cache Creek Terrane collision, mid-Cretaceous contraction causing northwest-trending folds and northeast-directed thrust faults, Late Cretaceous to Eocene crustal extension leading to grabens and horsts, and Eocene or younger northwest-southeast crustal extension involving tilting of fault blocks. The majority of copper mineralization within the Babine Porphyry Belt is related to Babine Intrusions which are comprised of small plugs and dikes of crowded biotite ± hornblende feldspar porphyry, quartz ± biotite feldspar porphyry, and equigranular hornblende-biotite granodiorite to quartz diorite. Dated to the early Eocene (49 to 53 ma), these intrusions are considered the subvolcanic roots of a calc-alkaline magmatic arc, intruding Triassic to Early Cretaceous volcanic and sedimentary host rock strata. The predominant rock type in the Babine Intrusions is a crowded biotite-feldspar porphyry, occurring as small plugs, stocks and dikes. These intrusive bodies are primarily diorite to granodioritic in composition and presumably cut earlier equigranular granodiorite and quartz diorite stocks. Northeast to north trending dikes of biotite-feldspar porphyry often show associated copper mineralization and intense alteration. These stocks, associated with zones of biotite hornfels and disseminated pyrite, can host low-grade copper mineralization, with higher grades typically associated with younger porphyritic phases. Outcrop in the Mt Horetzky project area is sparse due to widespread ovglacial and alluvial overburden, and much of the geology is inferred. Mt Horetzky is underlain by a partially exposed diorite stock which has hornfelsed surrounding units. Later porphyry dykes are found cutting all units. Pyrite, chalcopyrite and molybdenite occur within the diorite, dykes and hornfelsed rocks as disseminations, fracture fillings and within quartz stockworks, with native copper and chalcocite also having been noted. Hornfelsed rocks are variably sericite altered and silicified and are leached, bleached and quartz stockwork in several areas. Diorite is typically weakly chlorite altered and ranges from a fine-grained biotite diorite to a medium grained sub-porphyritic biotite hornblende diorite. The most abundant type of dyke is a coarse-grained plagioclase biotite porphyry with a dark, fine-grained matrix. Although alteration within dykes is rarely intense and typically consists of fracture related chloritization, at least one dyke, located in an area of reduced magnetic susceptibility, is completely clay and quartz-sericite altered. Dikes and jointing typically trend northwest or northeast. Historical surface soil and rock sampling has been undertaken over multiple seasons, with inconsistent analytes and sample protocols, and non-standard QC. Surface geochemical data are considered as-is, with anomalies identified on a relative basis. Surface geochemistry has outlined an anomalous Cu area of approximately 2x2.4km, which correlates spatially to the strongly magnetic porphyry intrusive body. The CJL showing discovered in 2014 is described as altered metavolcanic with disseminated and vein sulphides, with assays >1% Cu and 277.7 ppb Au, which is indicative of high grade portions within the mineral system. Surface sampling has not covered the intrusive entirely, and extension of mineralization may continue to the south and west. In summary, the surface (rock and soil) geochemistry confirms widespread copper anomalism over a wide area, which supports the fertility and tenor of the mineralizing system. In 1972, McPhar Geophysics conducted an IP/Resistivity survey for Hecla Operating Company over the core of the Mt Horetzky porphyry intrusion. It appears though the historical drilling was focused on the area of anomalous Cu geochemistry, with drillhole targets on anomalous IP response. However, because the data were not inverted to “real earth” sections, the holes did not intersect the strongest IP response due to the inherent distortion of the electrode array pseudosections. Digital Elevation Models (DEM) reflect subsurface features such as faults, surface drainage, and resistance to weathering which are important to interpretation of surface geochemistry, geologic mapping, and structure. The DEM over Mt Horetzky indicates a topographic high over the east half of the porphyry intrusion caused by differential weathering of silicification in the alteration halo related to the porphyry system. Many lineaments in the DEM are rectilinear, reflecting the general NW-SE tectonic fabric.