The British Columbia ROCKHOUNDER SILENCE
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The British Columbia ROCKHOUNDER #6 - 2401 Ord Road Kamloops, BC V2B 7V8 Published quarterly by the British Columbia Lapidary Society Executive of the Society SILENCE President Rudy Zimmerman There is a silence that you hear and feel, deep Past President Win Robertson 1st Vice President John Bowman in the woods or at sunset in the desert. 2nd Vice President Harley Waterson When for a few moments the birds are hushed 3rd Vice President Randall DeFuhr and the wind is stilled, but the most silent si- Treasurer Diane Bowman lence in the world is when the President of the Executive Secretary Donnamae Chionis Recording Secretary Terry Bacon Society asks for a volunteer. Please stop sitting on YOUR good intentions and dare to say, YES, I’LL HELP. Remember, Address of the Society it’s not THEIR gem show or SOMEONE ELSE’S 1160 Sealord Road Gem show, it is EVERY MEMBERS show and Richmond, BC V7A 3L2 PH. 604-277-3222, Fax 604-821-4603 YOU are needed to make it a success. E mail: [email protected] Please remember, being busy may be a reason, but not an excuse. Everyone is busy. Your help is needed on the BC Gem Show com- Contents mittee and at the Show, so say YES when called on, or be daring…… Geological Diversity: northen BC has it all ...................... 1 Making the Leap ............................................................ 5 Prospecting for Opal ....................................................... 6 Gemstones in Folklore - part 2 ........................................ 13 VOLUNTEER Rockhounding at the East End of Taltapin Lake ............. 14 via the Pegmatite Bulletin 10/02 (with changes) Tracking the North Magnetic Pole ................................... 17 Armchair Prospecting in B.C.-part 2 ............................... 19 Cover Picture Salt Casting ..................................................................... 21 But Seriously Folks ......................................................... 22 The Attraction of Rockhounding ...................................... 23 Agate Nodules collected by Ian Mcewen In Search of Buse Lake Blue .......................................... 24 At the east end of Taltapin Lake Zone Reports .................................................................. 25 Around the Clubs ............................................................ 26 Photo courtesy of Ian Mcewen Club Shows ..................................................................... 31 Rendezvous 2003 ........................................................... 32 To Advertise in the Rockhounder Summer Camp 2003 ....................................................... 33 Full page $50.00 per issue Half page $25.00 per issue Quarter page $12.50 per issue Write about it! Business card $5.00 per issue Share your adventures and knowledge by sending an For more information contact: article to the Rockhounder Win Robertson Submit articles for the next issue by FEB 15, 2003 6 - 2401 Ord Road to: Win Robertson Kamloops, BC V2B 7V8 60 -15875 20 Avenue, Tel. 250-376-4878. Surrey, BC V4A 2B1 E mail: [email protected] E mail: [email protected] When you advertise in the Rockhounder Thanks to all that have submitted articles & club news your company name & phone number are placed for publication. They are greatly appreciated and on the Lapidary Society web page enjoyed by our readers. http://www.lapidary.bc.ca/magazine.html 1 Geological diversity: northern BC has it all By Al Price The geology of northern BC is as fascinating and diverse Yukon border, and from near Terrace east to around as anywhere in the world. Burns Lake. The Cache Creek Terrane is a narrow sliver About 4.5 billion years ago, when the earth's outer skin running from its namesake in the south through Vander- started to cool, separate slabs of rock known as tectonic hoof and north, and the Quesnellia Terrane runs from the plates, banging up against each other, forced some areas US border with the Kootenays through Prince George, upward into mountain ranges, other parts downward, and narrowing as it meets the thin strip of remaining Cassiar where cracks in these giant slabs occured, molten Terrane. magma rose and igneous intrusions or volcanoes formed. All of which, to make a long story short(er), explains Northern BC went through all of these processes, why oceanic fossils can be found in the Rockies and why and the changes are still taking place. Earthquakes re- in Smithers and everywhere else in northern BC, rocks mind us frequently of the earth's shifting plates, and found in one spot can be totally unrelated to others found mountains accurately measured many years ago may five metres away. Igneous rocks, formed from molten now be a few inches higher or lower. matter deep inside the earth, have squeezed upwards to Some 200 million years ago, there was no northern BC fill cracks, or occasionally spill out as lava or magma, right as we know it now. In fact there was no BC at all west of next to the sedimentary rocks containing fossils, or meta- the Rocky Mountains. In the north, likely around Dawson morphic rock which has been greatly altered from its origi- Creek, the land of North America sloped off into the sea nal state. where, for the previous 1,500 million years, sediment had In the Tertiary epoch, BC was the focus of large and been deposited on the continental shelf that stretched small volcanoes, some of which were silica-rich, forming from the Okanagan through Quesnel to Cassiar. Up to typical cones and domes, and others more iron- 2,000 kms offshore, the volcanic island chains of Ques- magnesium rich that formed broad flat flows such as are nellia and Stikinia sat on two terranes, exotic pieces of the seen in the Cariboo. There were also many inter-volcanic earth's crust which still exist today but in much different sedimentary basins in which we now find well-reserved form and location. Other terranes now part of BC may fossils, such as Princeton, Kamloops, and Driftwood actually have been forming farther south, and then slid Creek near Smithers. into place along major faults such as the San Andreas The age of glaciation, culminating about 10,000 to Fault. 20,000 years ago ground at the mountains, creating huge When the pattern of plate movement changed and the lakes such as Babine, and deposited enormous amounts continent began moving west, it inevitably collided with of sediment at river mouths. (At one time, the headwaters these island terranes some 181 million years ago, in a of the Skeena River, including the Babine system, were slow-motion process which was most dramatic, but which dammed by huge chunks of ice, forcing its waters to flow also took 30 million years. out through the Nechako River into the Fraser. A large Between the islands and the mainland of the day, was glacial lake formed in the plains around Vanderhoof.) the seafloor of the Slide Mountain Terrane, and between While this hodgepodge of relatively new rock adjacent the island arcs was the limestone rich seafloor of the to ancient formations has made it much more difficult to Cache Creek Terrane. All four are now known as the In- unravel the history, it has also made northern BC a haven termontane Superterrane, which collided with the conti- for geologists. Among the foremost in their field is Smith- nental shelf. ers geologist Tony L'Orsa, who was born and raised in Rather than sliding below the shelf in a relatively the area and has produced numerous papers and reports peaceful process, portions of each terrane began to peel on the geological history of the region. off, and the rocks were jammed and folded into what are On a web site dedicated to Fossils of North-central now the Cassiar, Omenica and Columbia mountains. By British Columbia, L'Orsa points out that "... volcanic ash 120 million years ago, the western edge of the Rockies and flows showered down on swamps and forests in a was stacking up. At about the same time, the Wrangellia climate like that of North Carolina today, in the Creta- and Alexander terranes were meeting up with the Stikinia ceous period of 140 to 65 million years ago. Coal fields Terrane to create more mountains. were formed locally (at Telkwa, among other sites), indi- The Wrangellia Terrane is now manifested as the cating a moist climate with thick forests." Queen Charlotte Islands, Vancouver Island and parts of Even though glaciers did deposit till on many of the the coastal areas from the Sunshine Coast north to the valley floors, they also exposed fossil beds in numerous area opposite the northern tip of Vancouver Island. The places. Fossil sites from many different ages are listed on Alexander Terrane is a thin strip of islands and coastline the site, including those being formed today in calcareous from Central springs that are scattered around the area and at sites of BC through Alaska. Another thin strip of Undivided active iron oxide deposition in Silver King Basin and near Metamorphic Rock formations extends from the Lower the Telkwa Pass. Mainland north through Terrace and up along the Alaska- "Also of interest is the discovery of the remains of a BC border. The Stikinia Terrane cuts a wide swath from mammoth, dated at about 34,000 years before present, the Cache Creek area north through Smithers to the found in a silty pond deposit during stripping at the Bell 2 copper mine on Babine Lake in 1971," L'Orsa says. The Eagle Creek occurrence is commonly referred to Among the best known of the many fossil sites is Drift- as "Eagle Creek Agate and Opal Beds". It is located ap- wood Canyon Provincial Park, just north of Smithers proximately 6.5 kms from Burns Lake. Walking time from towards the Babine Mountains. the picnic area to the opal/agate bearing outcrops is The lands on which the fossils are found was gener- about 30 minutes, but it involves some steep climbs. Min- ously willed to the province provided that visitors are not eral collecting is permitted in this area which has been prohibited from collecting fossils.