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Jurassic Forum » JURASSIC references & paper reviews » Jurassic around the world » Kyba J., Nelson J.L. (2015) (Stratigraphic and tectonic framework of Iskut River)
Kyba J., Nelson J.L. (2015)
mhornДата: Wednesday, 18.02.2015, 17:24 | Сообщение # 1
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Kyba J., Nelson J.L. (2015) Stratigraphic and tectonic framework of the Khyber-Sericite-Pins mineralized trend, lower Iskut River, northwest British Columbia // In: Geological Fieldwork 2014, British Columbia Ministry of Energy and Mines, British Columbia Geological Survey Paper 2015-1, pp. 41-58.

The Khyber-Sericite-Pins trend is part of the ‘Bronson corridor’, a belt of mineralization in northwest Stikinia that extends southeast from the past-producing Snip and Johnny Mountain gold mines. Within the mineralized belt, a series of Early Jurassic (195-190 Ma) plutons, stocks and dikes of the Lehto plutonic suite cut stratifi ed Stuhini Group and Hazelton Group rocks. Large quartz-sericite-pyrite (QSP) alteration zones and precious-metal veins and stockworks are spatially associated with the intrusive suite. The corridor is bounded to the southwest by the Sky fault system, a 20 kilometre-long set of normal faults and reactivated post-mineral reverse faults. Notable among the latter is the Khyber reverse fault, which forms the immediate hanging wall to intense QSP alteration and mineralization at the Khyber-Inel prospects. Previous workers distinguished between the Stuhini and Hazelton groups on chronostratigraphic grounds, placing the contact at the Triassic-Jurassic boundary (201 Ma). In contrast, we use lithostratigraphic criteria, and place the base of the Hazelton Group at an angular unconformity cut into Stuhini Group volcaniclastic rocks that is overlain by a distinctive Upper Norian conglomerate-bearing siliciclastic unit, herein referred to as the Snippaker unit. The Snippaker unit consists of polymictic conglomerate, arkose, and siltstone. It is compositionally mature relative to Stuhini Group strata beneath the unconformity. Coeval with Late Triassic porphyry deposits of Stikinia such as Red Chris, the unit records the termination of Stuhini arc volcaniclastic sedimentation and erosional unroofi ng of the Stuhini Group. Very coarse, immature lower Hazelton Group conglomerates near the Sky fault zone south of Mt. Johnny indicate steep local slopes and clast contributions from a variety of nearby sources. Previously brecciated hypabyssal intrusive clasts in one of the deposits suggest deposition proximal to a penecontemporaneous fault. The structural and stratigraphic setting of the Khyber-Sericite -Pins trend closely resembles that of the Kerr-Sulphurets-Mitchell-Brucejack porphyry-epithermal camp. The Sky fault system appears to have played a similar role to that of the Sulphurets thrust and its precursor basin-bounding faults, in localizing Early Jurassic intrusion and mineralization. The Khyber reverse fault, with its highly QSP-altered footwall, is a close analogue to the Sulphurets thrust fault. In both cases, Cretaceous thrust reactivation was facilitated by mechanically weak, highly altered, clay-sericite-rich rock

Middle Jurassic - Lower Cretaceous ammonites & aptychi
Jurassic Forum » JURASSIC references & paper reviews » Jurassic around the world » Kyba J., Nelson J.L. (2015) (Stratigraphic and tectonic framework of Iskut River)
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