Geology And Minerals Of Northern B.C.

Geology

About 4.5 billion years ago, the earth’s outer skin started to cool, creating separate slabs of rock known as tectonic plates. Though we may think of rock as hard and stable, the plates are anything but. The heat of the earth itself causes the plates to float and move, banging up against each other, forcing some areas upward to create mountain ranges, while other parts are forced down. Where cracks in these giant slabs occur, molten magma rises and igneous intrusions or volcanoes are formed.

Northern BC has gone through all of these processes, and the changes are still taking place. Earthquakes remind us frequently of the earth’s shifting plates, and mountains accurately measured many years ago may now be a few inches higher or lower.

Some 200 million years ago, there was no Northern BC as we know it now. In fact there was no BC at all west of the Rocky Mountains. In the north, likely around Dawson Creek, the land of North America sloped off into the sea where, for the previous 1,500 million years, sediment had been deposited on the continental shelf that stretched from the Okanagan through Quesnel to Cassiar. Up to 2,000 kilometres offshore, the volcanic island chains of Quesnellia and Stikinia sat on two terranes, exotic pieces of the earth’s crust which still exist today but in much different form and location. Other terranes now part of BC may actually have been forming farther south, and then slid into place along major faults such as the San Andreas Fault.

When the pattern of plate movement changed and the continent began moving west, it inevitably collided with these island terranes some 181 million years ago, in a slow-motion process which was most dramatic, but which also took 30 million years.

Between the islands and the mainland of the day, was the seafloor of the Slide Mountain Terrane, and between the island arcs was the limestone rich seafloor of the Cache Creek Terrane. All four are now known as the Intermontane Superterrane, which collided with the continental shelf. Rather than sliding below the shelf in a relatively peaceful process, portions of each terrane began to peel off, and the rocks were jammed and folded into what are now the Cassiar, Omenica and Columbia mountains. By 120 million years ago, the western edge of the Rockies was stacking up. At about the same time, the Wrangellia and Alexander terranes were meeting up with the Stikinia Terrane to create more mountains.

The Wrangellia Terrane is now manifested as the Queen Charlotte Islands, Vancouver Island and parts of the coastal areas from the Sunshine Coast north to the area opposite the northern tip of Vancouver Island. TheAlexander Terrane is a thin strip of islands and coastline from Central BC through Alaska. Another thin strip of Undivided Metamorphic Rock formations extends from the Lower Mainland north through Terrace and up along the Alaska-BC border. The Stikinia Terrane cuts a wide swath from the Cache Creek area north through Smithers to the Yukon border, and from near Terrace east to around Burns Lake. The Cache Creek Terrane is a narrow sliver running from its namesake in the south through Vanderhoof and north, and the Quesnellia Terrane runs from the US border with the Kootenays through Prince George, narrowing as it meets the thin strip of remaining Cassiar Terrane.

All of which explains why oceanic fossils can be found in the Rockies and why in Smithers and everywhere else in Northern BC, rocks found in one spot can be totally unrelated to others found five metres away. Igneous rocks, formed from molten matter deep inside the earth, have squeezed upwards to fill cracks, or occasionally spill out as lava or magma, right next to the sedimentary rocks containing fossils, or metamorphic rock which has been greatly altered from its original state.

Fossils

In the Tertiary epoch, bc was the focus of large and small volcanoes, some of which were silica-rich, forming typical cones and domes, and others more iron-magnesium rich that formed broad flat flows such as are seen in the Cariboo. There were also many inter-volcanic sedimentary basins in which we now find well-reserved fossils, such as Princeton, Kamloops, and Driftwood Creek near Smithers.

The age of glaciation, culminating about 10,000 to 20,000 years ago ground at the mountains, creating huge lakes such as Babine, and deposited enormous amounts of sediment at river mouths. (At one time, the headwaters of the Skeena River, including the Babine system, were dammed by huge chunks of ice, forcing its waters to flow out through the Nechako River into the Fraser. A large glacial lake formed in the plains around Vanderhoof.)

While this hodgepodge of relatively new rock adjacent to ancient formations has made it much more difficultto unravel the history, it has also made Northern BC a haven for geologists. Volcanic ash and flows showered down on swamps and forests in a climate like that of North Carolina today, in the Cretaceous period of 140 to 65 million years ago. Coalfields were formed locally (at Telkwa, among other sites), indicating a moist climate with thick forests. Even though glaciers did deposit till on many of the valley floors, they also exposed fossil beds in numerous places.

Fossil sites from many different ages including those being formed today in calcareous springs that are scattered around the area and at sites of active iron oxide deposition in Silver King Basin and near Telkwa Pass. Also of interest is the discovery of the remains of a mammoth, dated at about 34,000 years before present, found in a silty pond deposit during stripping at the Bell copper mine on Babine Lake in 1971.

Among the best known of the many fossil sites is Driftwood Canyon Provincial Park, just north of Smithers towards the Babine Mountains. The lands on which the fossils are found was most generously willed to the Province of BC provided that visitors are not prohibited from collecting fossils. Plant, insect and occasionally fish specimens can be found in the thinly laminated shale, which formed from eruptions of fine volcanic ash from the neighboring Babine Mountains into a small freshwater lake. There would seem to be a good chance that small mammals, birds and perhaps even amphibians might also be found. Some of the leaf fossils at Driftwood, the Metasequoia (Dawn Redwood) and Ginko are species that still exist in China.

Examples of petrified wood and marine fossils including ammonites (coiled squid-like animals) can be found in the Skeena Group formation. Sedimentary rock of the Middle Jurassic-Lower Cretaceous period yields some ammonites and gastropods (snails), as well as many types of pelecypods (oyster relatives) in the sand and siltstone of the Trout Creek outcroppings where it meets the Bulkley River between Smithers and Moricetown. The first known coral reef of Jurassic age (Sinemurian) found in North America, and perhaps the world, outcrops in the Telkwa Mountains.

Other fossil sites occur at Ashman Ridge, the Spatsizi Plateau, along Babine Lake Road, Dome Mountain, Perow, near Granisle, and at Copper River near Terrace, as well as Silvern Lakes near Smithers and in many places on the Queen Charlottes. Multi-lobed clay concretions, which look like alien fossils, can be found in the clay banks of the Bulkley River. Visitors are reminded that collecting fossils anywhere in BC for the purpose of sale in any form requires a site-specific permit and is closely regulated.

Prospecting For Minerals

Prospecting for minerals, particularly precious metals, was a major factor in the early settlement of Northern BC, with everything from gold, silver, lead and zinc to copper and molybdenum being found in a wide area. Many productive mines have been operated over the years and some are still in production. But a fairly steady decline in the price of base metals, creation of new parks and protected areas, native land claims and strict environmental regulations have curtailed much of the exploration once done in this area. Interests have turned to precious stones, and there are now major efforts underway to determine the extent of an opal deposit in the Whitesail Mountains of the Ootsa Lake region, new jade discoveries in the Dease Lake area, and emerald deposits recently discovered on the BC-Yukon border.

Opals

While prospector Bob Yorke-Hardy, formerly of Smithers, discovered the Klinker opal deposit in 1991 and has since developed the Okanagan property into the first working opal mine in Canada, Northern BC is not without opals. Best known is the Eagle Creek Provincial Park deposit outside of Burns Lake where rockhounds can find small samples of the glowing stone for their collections. Opals have also been found along with chalcedony, calcite, chlorite and quartz-filled amygdules at the south end of Sloko Lake, about three miles south of Atlin Lake.

The Eagle Creek occurrence is commonly referred to as “Eagle Creek Agate and Opal Beds”. It is located approximately 6.5 kilometres from Burns Lake. Walking time from the picnic area to the opal/agate bearing outcrops is about 30 minutes, but it involves some steep climbs. Mineral collecting is permitted in this area which has been withheld from staking by the town of Burns Lake, having turned it into a park. Agate nodules and common opal are abundant. Rare fire opal but no precious opal has been found there.

And though some high quality opals have been found at Maxan Lake and in rock faces on the many logging roads around the Burns Lake area, the most exciting find is Bruce Holden’s North Lights claim. It sits in the alpine area of a mountain north of Tahtsa Lake and Tweedsmuir Park, 90 kilometres south of Houston by helicopter.

Still in the explorative stages, the Northern Lights property has yielded a combination of common and precious opal. Its types range from nodules similar to Mexican opals, thin sheets that resemble Queensland boulder opal, to matrix opal in which the matrix ranges from hard and polishable black basaltic material to much softer brown stone. Clarity varies from opaque to transparent, and some even exhibits the highly prized red and green flashes.

Many top-quality agates have also been found at this deposit, including one which combined agate and opal. White or greenish attractive opal can be found in water-washed pieces at Francois Lake on the beaches.

Jade

Northern BC has always been known for its jade deposits, from Ogden Mountain near Germanson Landing to Cassiar, where top-quality nephrite jade was pitched into the waste piles as miners excavated the highly valued asbestos around it. (When the value of the jade was realized, the sale of jade contributed thousands of dollars to the recreation fund at the mine.) The alluvial deposits of jade in the area were discovered by early Chinese miners, and shipped back to China where the stone is revered for carving and tools. These visitors were not the first to use the versatile material, however, as several jade implements have been found in archaeological digs, indicating use by the area’s first inhabitants. Much of the BC jade production is still shipped to China where it is made into beads, cabochons and carvings. However, BC carvers also turnout many prized carvings.

Cassiar jade is unusual in that it contains specks of uvarolite (chrome bearing) garnet, one of the rarest of gemstones, which gives the jade its brighter, emerald-green color. Jade can also be found at Provencher Lake, 80 kilometres east of Dease Lake.

Emeralds

In the fall of 1998, Expatriate Resources Inc. discovered emeralds at the Goal Net Property in the Finlayson Lake District of southeast Yukon. (pale beryl or emerald had previously been found in pegmatite bodies near Rancheria on the BC-Yukon border.) In June of 2001, True North Gems acquired the Regal Ridge Emerald project from Expatriate Resources, and sampling and processing of subcrop and talus material has produced numerous small, gem quality emeralds with excellent color and clarity. Much work has yet to be done, but the discovery has sparked renewed interest in gemstone possibilities in the area.

Queen Charlotte Islands

Grossular garnet in yellowish-white crystals can be found at Lepas Bay, south of Cape Knox on the northwest tip of Graham Island. The crystals are said to be perfectly formed trapezohedrons.

Agates and chalcedony have been found along the northern shorelines of Graham Island, and along the southeastern shores near Skidegate.

Many ammonite localities are found in sedimentary rock near Queen Charlotte City. The source of the argillite for the famed Haida carvings is kept secret and is not open to the public. Many old mines such as Tasu have dumps with crystals, sulphide minerals and garnets or magnetite.

Prince Rupert

Metamorphic schists in this area are part of a belt which extends to Wrangell, Alaska. Some almandine garnet crystals found are 1 inch in size. Other minerals such as kyanite (pale blue), staurolite (pink to brown) and pyrite may also be found in this area. There is also an area of petrified wood at Alastair Lake.

Stewart-Cassiar area

Petrified wood can be found in the Hank Creek – Ball Creek area 10 km. west of the Stewart-Cassiar Road. Emerald-green beryl can be found in the narrow quartz-calcite-pyrite veins on Red Mountain near Stewart, on Ash Mountain near Cassiar and near Surprise Lake near Atlin. Others have been found in the surrounding area, though they are small, fractured and often opaque.

Cassiar-McDame

Beryl (Aquamarine) has been discovered in the Horseranch Range (near McDame, 150 kilometres north of Dease Lake and southeast of Cassiar), and at Mount Foster near Bennett. Also found in the area are topaz, smokey quartz, phenacite, fluorite and microline.

Also in the Horseranch Range can be found garnet (Hessonite), some of which are a rich orange color which produce stunning gems when cut, and rose and smoky quartz, which ranges from very light to very dark. One cut specimen of 80.75 carats was extracted from Mount Foster.

Placer gold was found in many of the creeks in this area, and panning can still turn up small “colors.” More recently, very attractive pink rhodonite has been mined near Cassiar, and attractive quartz, serpentine (for carving) and asbestos are common.

Dease Lake

Transparent crystals of pyroxene, peridot and olivine can be found in some of the volcanic rocks in the Dease Lake area.

Atlin Lake

Red jasper occurs in the chert rocks at Sentinal Mountain (east side of Atlin Lake, 20 km. south of Atlin village,with a road to the base from the village) and Gold Bottom Creek (a tributary of Sloko River). Some rare purple and lavender varieties have been reported. East of Atlin, crystals of colorless topaz have been found on the surface, with some specimens being quite large (65 carats uncut). Underground, the crystals are champagne-colored.

Sloko Lake

Opal, Chalcedony, calcite, chlorite and quartz-fillamygdules in the basalt flows at the south end of the lake, about three miles south of the south end of Atlin Lake.

Stikine River

Perfect, clear-red almandite garnet crystals up to 3 cm. in diameter occur in mica schist along the Stikine River near the mouth of the river.

Terrace

Near Kalum Lake, there is a deposit of Chiastolite, (Staurolite crystals with carbon segregations in symmetrical distribution). Amethysts in quartz veins in granitic rock were discovered in the 1960s by prospectors Art and Dick Bates and can be found at the west-end of the old highway bridge at Terrace. One of the better specimens is a 10.19 carat pale-colored amethyst now in the collection of the University of BC.

Hazelton area

Crystals of white scheelite measuring two inches in diameter have been found in the quartz-rich fissures of the Rocher De Boule mine, which is up an 12.8 km. road heading east from Skeena Crossing. Some even larger crystals have been reported. Other minerals include quartz, hornblende, actinolite, feldspar, calcite, siderite, chlorite, titanite, tourmaline and rutile. Also, apatite can be found as pale gray to greenish white prismatic fibrous crystals up to 1inch across and 6 inches long. Similar materials are found at the Red Rose Tungsten Mine, 5 km. south of Rocher De Boule.

Smithers

The Cronin Babine Mine and Duthie (Sil Van) Mine were both high grade silver-lead-zinc ores, with good specimens in the dumps. There are hundreds of prospects on Hudson Bay Mountain, most around the large Glacier Gulch intrusion. The late Bill Yorke-Hardy, newspaper editor and prospector found a very large molybdenite deposit directly under the glacier. Someone actually suggested dusting the glacier with coal dust to melt it more quickly, however Mother Nature seems to have done just that over the years. In the gulch itself, there are also old gold and silver veins, one with native gold.

Telkwa Range

Well known Smithers prospector Lorne Warren found a deposit of deep blue lazulite (not lapis) in the Telkwa Range. There are hundreds of prospects in this area, mainly copper. In years past, the Telkwa coal beds kept many an area family warm during the winter.

Houston

This area has been a haven for prospectors, such as the legendary “Kid” Price, Bill Sweeney and E.G. Bellicini.Thousands of claims have been staked on deposits of silver, copper, lead, zinc and gold, but few mines resulted. The Equity Silver mine closed in 1994 and Huckleberry Copper is still operating in the Tahtsa Reach area, but few of the exciting deposits have sufficient reserve quantities, though they do provide excellent mineral samples. Old placer gold workings can still be found a few kilometres south of Houston on Buck Creek. The Nadina Mine near Owen Lake 48 kilometres south of Houston has beautiful crystals of galena, sphalerite-banded cockscomb quartz, some chalcedony, rhodochrocite and manganese carbonate. The mine is flooded and closed, but material can still be found on the dumps. This is on the road to the Huckleberry mine. Nearby on Sweeney Mountain near Tahtsa Reach are the high grade silver deposits found by Sweeney. West of Houston towards Smithers, Hungry Hill and Grouse Mountain are riddled with old shafts and tunnels. Bill Yorke-Hardy found a molybdenum deposit in one or more large breccia pipes associated with an “alaskitic” (light colored granite) intrusion. At the top of the mountain is a small but interesting copper-zinc deposit, which Barry Price explored many years ago. Agates can be found at Barrett Hat, a small volcanic neck west of the highway.

Burns Lake-Francois Lake

Beautiful agates can be found on the beaches and in some rock outcroppings, as well as thunder eggs (agate-lined cavities weathered into round balls), amethyst and opal. One agate weighing 300 lb. was found near Burns Lake. A beautiful agate resembling the Mexican red agate can be found on the shores of Francois Lake. It is banded and varies in color from pink to scarlet, found both in pebbles and nodules in the basalt along the shoreline. Associated with this deposit are geodes containing quartz (some amethystine) crystals.

A rare phosphate mineral known as Collinsite can be found with quercyite nodules in a vein of andesite at the Collier Ranch, 3.2 km north of the Francois Lake post office. The nodules are from 208 inches in diameter and are composed of both collinsite and quercyite arranged in concentric layers of radial fibres. The light brown fibres have a silky luster, and the nodules are coated with black asphaltum. The deposit may have been formed by metamorphism of “guano.”

Tchesinkut Lake, north of Francois Lake, is known as a source for good quality blue agates. Chalcedony nodules can be found on the shores of Ootsa Lake. In the Kenny Dam area, an attractive jasper/agate occurs in shades of blue and brown in a one-foot vein about 3.2 km. north of the dam, opposite a slide on the west bank, about an hour’s walk off a road which stretches 96 kilometres south of Vanderhoof. Agates can also be found along the road and in the adjacent streams along the way.

Whitesail Mountains

In addition to the opal and agate already mentioned, there are occurrences of unusual “pineapple” and “hedgehog” shaped quarts crystals and clusters.

Granisle

A huge copper deposit was the base of this community for many years, but it is now closed. A similar deposit, Bell Copper is situated to the North of Granisle on Newman Peninsula. Copper resources remain at Bell, but copper economics are no longer favorable there. Silver mineralization was known in small veins on Silver Island and at Taltapin Creek, where an early promoter envisioned a railway and power dam.

Endako

A major molybdenum mine is still operating 8.5 km. south of this community. Interesting yellow oxides of molybdenum and uranium are present on Nithi Mountain.

Fort Fraser

Amber occurs in the black lignite beds of the Nechako River to the south of this community.

Stuart Lake

Agates are found on the beaches, most abundantly reported at the Sowchea Bay area due west of Fort St. James on the southwestern end of the lake. The old Pinchi Lake mercury mine, operated for many years by Cominco, has interesting cinnabar specimens and high-pressure metamorphic minerals glaucophane and possible jadeite.

Prince George

Agates ranging from red to honey brown and black can be found in the gravels of the Nechako and Fraserrivers in this area. They include moss, iris, turtleback, dendritic and sagenitic patterns. Fragments of petrified wood can also be found. Best collecting spots are the Miworth gravel pit about 12.5 km. west of Prince George, and at the Big Slide on the north side of the Nechako about 11 km. west of Prince George. Dark red garnet (Almandine) crystals can be found in the granite pegmatite in the Prince George region, with transparent red specimens of up to 5 – 6 mm found in the river gravels of the Fraser.

Quesnel

Agate and jasper are found in Hixon and Ahbau creeks, north of Quesnel, and in other streams around thecommunity. Ahbau Creek also has locations where gold specks can still be panned. Small grains of amber have been reported in the lignite beds on the south bank of the Quesnel River. Some up to 2.5 cm. have been found in a yellow color with greenish tinge, with occasional plant inclusions. Historically, the Barkerville and Wells areas have placer and lode gold mines, and nuggets or jewellery can be bought from several local dealers.

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