The Lorraine property area occupies the north eastern part of the Duckling Creek syenite located within the central part of the Hogem batholith in British Columbia. The rocks of the Lorraine property area consist of "metasomatic syenites" or "fenites" formed by the metasomatism of the fractured Hogem diorite. They are believed to have been derived from a hypothetical alkaline magma formed beneath the diorite. The residual magma differentiated from the alkaline magma, produced late dykes and hydrothermal fluid. A K-Ar date, 170±8 m. y.(Lower Jurassic) may correspond to both the minimum age of the fenites and the maximum age of the sulphide mineralization at the Lorraine property. Also, the age may mark the time point dividing the first division and the second division of the Hogem batholith. The characteristic minerals of the successive stages of alteration are 1. biotite, 2. albite, 3. orthoclase, if. quartz, 5. sericite, 6. chlorite, and 7. epidote. The altering fluid contained concentrations of soda, potash, silica, hydrogen sulphide, water, and a minor amount of lime. The primary sulphides are bornite, chalcopyrite, and pyrite. The Lorraine deposit posseses no noticeable gossan, but contains secondary copper minerals such as covellite, chalcocite, azurite and malachite. The deposit is divided in plan into three mineral zones on the basis of the primary sulphide assemblages. The dykes, mafic rocks, and fractures were the main controls of mineralization. The composition of the hydro thermal, fluid changed as sulphur reacted with iron of the host rock to form pyrite. The reduced sulphur ratio appears to have caused deposition of bornite and chalcopyrite. In the mineral zones pyrite was replaced progressively by chalcopyrite and bornite. The best classification for the Lorraine deposit is xenothermal. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Rocks of the Hadrynian and Early Paleozoic (?) Snowshoe Group comprise the core of the Boss Mountain area at the western margin of the Omineca Belt near Crooked Lake. Structurally overlying these are rocks of the Intermontane Belt: the Permian Slide Mountain Group (Antler Formation), Triassic fine grained sediments (unnamed), and Jurassic volcanic rocks (Takla Group). In the Snowshoe Group, a large, lensoid intrusion of coarse grained granitic rock (Boss Mountain gneiss) was emplaced during the mid-Paleozoic, and later deformed and metamorphosed with the enclosing metasediments. The rocks of the Snowshoe Group act as basement to the overlying Late Paleozoic/Early Mesozoic cover rocks. Within the basement, four phases of regionally significant deformation have been recognized, and are manifest as fold generations designated Fl through F4. Earliest structures, Fl, in the Snowshoe Group are isoclinal folds, accompanied by a transposed foliation of regional extent, which are overprinted by penetrative deformation related to easterly verging F2 nappe structures. The F3 folds are upright or inclined to the northeast, and give a consistent southwesterly sense of vergence. These folds are responsible for the regional map pattern, and have folded both the basement and cover into an antiformal culmination in the Boss Mountain area. Fourth phase structures refold the other features, but do not appreciably affect the F3 geometry. In the cover sequences, the first phase of deformation is equivalent to the second phase within the basement During the Phase 2 deformational episode the cover rocks were emplaced over rocks of the Snowshoe Group. West-dipping imbricate faults characterize the western margin of the area, where basement rocks contain fault-bounded slivers of the cover, and the tectonic contact between basement and cover rocks is marked by a zone of mylonitization. Similarly, the F2 and F3 folding phases in the cover are equivalent to the F3 and F4 structures in the basement, respectively, but are only weakly developed in the cover. An early, enigmatic metamorphic event accompanied Phase 1 deformation in rocks of the Snowshoe Group. Field relations suggest that this was probably coeval with the mid-Paleozoic emplacement of the Boss Mountain gneiss. Metamorphism during the Jurassic was synchronous with F2 deformation in rocks of the Snowshoe Group, and resulted in Barrovian type mineral assemblages ranging from the biotite through sillimanite zones. The metamorphic grade increases from west to east; with only low grade metamorphism of the cover rocks in the study area. Phase 2 structures in the Snowshoe Group were overprinted by the peak of this metamorphic event, as indicated by staurolite through sillimanite zone assemblages. The Boss Mountain area is structurally correlative with rocks of the Shuswap Complex. These rocks appear to comprise a portion of the continental margin sedimentary wedge, which was overridden by an allochthonous terrane accreted to the western margin of North America in post-Early Jurassic times. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

The Monashee Complex is a structural culmination which exposes rocks from the lowest stratigraphic levels of the Canadian Cordillera. The Monashee Complex is subdivided into two lesser structural culminations; the Frenchman Cap and Thor–Odin culminations. The lithostratigraphic succession of the Thor–Odin Culmination is completely transposed by penetrative isoclinal folds with amplitudes from microscopic (<1 mm) to regional (10’s km). Lower structural levels are occupied by Proterozoic gneisses and migmatites of the Monashee basement assemblage. These are infolded with overlying metasedimentary rocks of the Monashee cover assemblage, which are Proterozoic to possibly Paleozoic in age. The basement and cover assemblages were subsequently intruded by Eocene granitic pegmatite, aplite and lamprophyre dykes. Regional metamorphism of the basement and cover assemblages reached upper amphibolite to lower granulite facies. The northeastern portion of the Thor–Odin Culmination of the Monashee Complex contains a suite of structures and fabrics, which are classified into four sets, based on their interpreted kinematic significance. These are: 1) transposition related structures (DT); 2) open, upright folds (DO); 3) exhumation related structures (DE); and 4) brittle faults (DB). Each successive set of structures exerted a control on the geometry of the next set. The large-scale geometry of the culmination is an interference structure between DT folds, a DE arch and high-strain zones, and a DB brittle horst. Early, DT fold style varies from intrafolial isoclinal “mature” style folds to upright or inclined asymmetric “immature” folds. This continuum of fold styles, along with evidence of anticlockwise rotation (looking down a vertical axis toward the shear plane) of fold axes and lineations is interpreted as being a result of penetrative triclinic non-coaxial flow. DO upright, symmetrical folds overprint early structures and fabrics, but are only preserved at low structural levels in the culmination where the DE coaxial stretching overprint is weak. DE normal shear bands and boudins overprint all earlier structures. A complex high-strain zone, the Thor–Odin High-Strain Zone, outcrops at high structural levels and along the margins of the culmination. The Thor–Odin High- Strain Zone developed as a result of material moving away from the crest of the culmination, outwards toward the flanks. Eocene brittle faults (DB) and fractures within the Thor–Odin Culmination of the Monashee Complex are divisible into three distinct sets. Initial 340–010º trending strikeslip faults (Set 1) were locally overprinted and reactivated by normal faults with a 325– 020º trend (Set 2). A third set of 255–275º trending fractures (Set 3) are interpreted as conjugates to Set 1, reactivated as transfer faults to the Set 2 normal faults. Large regional faults weather recessively forming topographic lineaments that transect the Monashee Complex. The Victor Creek Fault defines one such lineament. Detailed mapping within the northern Thor–Odin Culmination, reveals piercement points (fold hinges) on the east side of the fault, which are not readily matched on the west side. The minimum displacement required on the Victor Creek Fault to down-drop the fold hinge below the level of exposure on the west side is 1370 m, assuming normal down-to-the west displacement. However, the geometry of the fault is consistent with a Set 1 dextral strike-slip fault. Matching the piercement points in the study area with possible equivalents to the north indicates 55–60 kms of dextral strike-slip displacement. The Monashee Reflection (MR) is a major crustal-scale, cross-cutting reflection appearing on two mutually perpendicular Lithoprobe seismic profiles in the southern Omineca Belt of the Canadian Cordillera. It has previously been interpreted as the downplunge extension of an arched regional ductile thrust fault, the Monashee Décollement, and is described as separating the Monashee Complex from the overlying Selkirk Allochthon. Recent mapping demonstrates that this boundary is not a discrete ductile thrust, but rather transposed and gradational. Overprinting the transition zone is a complex, outward-dipping, normal, structure; the Thor−Odin High-Strain Zone. Three alternative 3-D geometric models have been developed for the MR in order to project the reflection to the surface. The favoured model correlates the surface trace of the Thor−Odin High-Strain Zone with MR. Normal shear sense kinematics are interpreted for the MR based on: 1) the overall geometry and asymptotic relationship between the MR and reflections in the hanging wall and footwall; 2) offset of metamorphic and geochronological gradients, consistent with an extensional zone, rather than with thrust fault interpretation and 3) the cross-cutting nature of the MR is consistent with normal structures throughout the region.