Geology of the Dodd Lake – Horseshoe Lake area

Geology of the Dodd Lake – Horseshoe Lake area
by Nancy Pezel, 21 April 2018

Tom Koleszar and Barbara Sherriff led an enthusiastic group of 26 members on a trip to learn about the geology of the local area.

Along with some great views at our first stop, Tom gave us a brief history of glaciation in the area.  We learned that a kilometre of ice covered the area some 12-13,000 years ago.  As the ice receded glacial streams flowed down the lower slopes and valleys, layering the rounded sediments.  These sediments are exposed nicely at the gravel pit at 12 Mile on the Goat Main.

On Beaver Main we stopped at an exposed rock cut and Barbara explained the processes of mineralization.  Who knew that rotten rock is a good thing?  Donning hard hats, we were left for a bit to prospect for pyrite, chalcopyrite, Molybdenum, and other minerals.  Unfortunately no one found any gold!

We then drove further up the road to Little Horseshoe campsite where we enjoyed our lunches and warmed up around David Bedry’s campfire and the sunny dock.  Barbara told us about physically staking mineral claims the old-fashioned way, as well as the new digital “click of a mouse” method on the BC government website.

After a short walk down the road, Barbara explained about plutons and fractures and we saw swarms of hydrothermal dykes of varying colours (and more rotten rock!) before we headed back home with our treasures.

Cortes Island geology

Cortes Island geology
by Tammy Siddall, 22 July 2015. 

It was a perfect July day in Lund when 12 naturalists boarded the Misty Isles in search of rocks. Captain Mike and crewmate Amy had planned an exciting two-day circumnavigation of Cortes Island for us.  From Lund Harbour we first headed north towards the Twin Islands.

As we travelled, co-leaders Barbara Sherriff & Tom Kolezar spoke about the geological formations and what we hoped to find.  We were on the lookout for dykes, which are sheets of igneous rock that form in fractures of existing rock.  We hit the mother lode arriving on Twin, where we hopped into the zodiac to head ashore.  The dykes did not disappoint!

From there we headed farther northwest around Cortes as Mike spoke to the group about Buchia, which are bivalve fossils.  His enthusiasm for Buchia was infectious and we followed a tip he had on a new specimen. It was a treasure hunt. We headed ashore and found the Buchia fossil. This was a hunt 140 million years in the making!

After a lovely lunch and some of the best cookies going, we travelled further around Cortes, learning the history of the region and spotting more dykes. With the informative rock lessons from our great leaders, no one on this trip will ever look at the shoreline the same way again.

An impromptu stop at Quartz Bay revealed a stunning dyke of quartz crystals. Tom and Barbara worked out that the existing rock setting in which the crystals formed was a sandstone while a foraging deer looked on. We even spotted a ‘cute’ dyke!

For the evening we headed to Read Island to stay at the Coast Mountain Expedition lodge. As we anchored in a bloom of moon jellyfish we knew we were in for something magical. The setting was serene and the hosts were marvelous.  As usual, the meal was awesome.  The next morning we had a lovely breakfast made by Lannie and Ralph, our lodge hosts and we were off in search of a copper and molybdenite deposit.

We travelled to the location of a stream that drains below a claim site on West Redonda Island.  Here we came ashore and we found assorted interesting cobbles including magnetite, basalt, diorite, granodiorite, and a rich sulphide. (You know the rocks are interesting when the geologists take back samples for themselves!)   Another treat at this location was the mysterious albeit beautiful gravestone belonging to two small children named Lucey.  The grave is still a mystery more than 100 years later.  The setting of the stream was idyllic and the water so clear that many of the group took time out to have a quick dip in the ocean.

Refreshed and renewed, we headed off in search of more ancestral pictographs. Mike once again regaled us with the history of the area, peppered like shiny mica, with the mystical stories as told by the area’s aboriginal communities.  After lunch, which included more of those great cookies (thanks Samantha!) we headed south towards geological formations known as xenoliths.  The xenoliths created wild patterns where they contrasted the host rock.  On our way to the xenoliths, we rounded a small island, which Mike calls Mini-Mittlenatch where we spotted many sea birds along-side seals nursing their young.

When we came into the Lund Harbour after an incredible day at sea, most of us realized our bags were much heavier than when we started.  Various rock samples of our treasure hunts were stuffed into our luggage.

For many of us on this trip the unfolding world of rocks was a new and tuff one, but after a fantastic two days we all agreed it was a blast!



Stephen Johnston – “Spain: Rocks, Romans and Rioja”

Stephen Johnston – “Spain: Rocks, Romans and Rioja”
by Andrew Bryant, 21 May 2015. 

Dr. Stephen Johnston, professor of geology at the University of Victoria, took us on a lively and all-encompassing journey to Spain.

Based on his extensive knowledge of Pangea, that supercontinent formed by wandering tectonic plates some 350 million years ago, Stephen gave a wonderful example of how everything is always connected to everything else.

Want to find gold in Spain?  Look for apple and chestnut trees, as these were often planted by the Romans while they were looking for gold.

Want to know why Las Médulas became a World Heritage Site?  Thank Pliny the Elder, who fortuitously published his notes shortly before his death in the Mount Vesuvius eruption in 79 AD.

Why is there a Sequoia tree growing at the University of Salamanca?  Because Christopher Columbus brought seeds back from America, at the same time that loads of Spanish mercury were being shipped to the New World to be using in gold mining operations there

In short, this was not your typical travelogue!

Tom Koleszar – “Exploring the Burgess Shale”

Tom Koleszar – “Exploring the Burgess Shale”
by Andrew Bryant, 19 Mar 2015. 

Tom Koleszar, geologist and vice-president of our club, took us on a sweeping, half-billion year-old exploration of the Burgess Shale.

This extraordinary rock formation, located in Yoho and Kootenay National Parks in the Canadian Rockies, contains one of the world’s richest deposits of fossils.  It is renowned for the quality of its fossils, especially as they allow for the preservation of soft-tissue imprints.   You can learn much more about it here, here and here.

It is truly extraordinary to look at a 500 million-year old rock and be able to count delicate hairs, eye facets or mouthpart details on an organism that was only millimetres or centimetres long when it swam or crawled through prehistoric seas.

Using photos, maps, and wit, Tom intoduced us to the fascinating world of the Cambrian, an epoch during which the oceans exploded into life.  To decribe creatures such as Anomalocaris, Hallucigenia and Opabinia as “strange” is a severe understatement – some of these things are downright weird!

There is also some fascinating human history surrounding these rocks, including that of discoverer Charles Walcott, who impressed his hardworking family into field technicians and porters, and the unresolved scientific debate between people such as Stephen Jay Gould and Simon Conway Morris.

Was the “Cambrian explosion” just a series of failed experiments in body type design?  Or the beginning of phyla that can be traced to this day?

As they say.  Time will tell.

Cortez Island Geology

Cortez Island Geology
by Tom Koleszar, 26 July 2014.

Twelve naturalists, led by our own Barbara Sherriff, boarded the Misty Isles with Captain Mike Moore for a day-long geological tour of Hernando, Twin, and Cortes Islands.

We first cruised past Hernando Island before landing at Iron Point at the south end of Twin Islands, where we had ample opportunity the get our hands on the rocks of Wrangelia and the Coast Plutonic Complex.  Back aboard the Misty Isles, we then cruised along the south shore of Cortes Island looking at recent Quaternary sediments and more examples of the plutonic rocks of coastal BC.

For the latter part of the afternoon, Captain Mike took us on a cruise around Kinghorn Island in Desolation Sound and then along the Copeland Islands and back to Lund.  Along the way we saw some wildlife and a rare Agarikon fungas on an old growth Douglas Fir (in addition to the rocks and beautiful scenery, of course!)

We had a wonderful day with great weather, and we all learned a lot about the geology of our own area.  Special thanks to Barbara and Mike Moore for making it all possible!