(see Creeks and Water and Mining)

The majority of the information presented in this section is summarized from the excellent book by Dr. Murray A. Roed and the geological society, Geology of the Kelowna Area, Ehmann Printing, Kelowna, 1995 and from a telephone conversation with Dr. Roed.

Smashing plates

The earth is estimated to have formed about 4.6 billion years ago. As it cooled, a hard crust of rock formed on its surface. This crust formed massive plates (Tectonic Plates) which still float on the underlying molten material much as ice sheets float on a pond. The underlying molten material is moving and as it does the plates drift slowly, crashing into each other. North America is one plate and another underlies the Pacific Ocean. The North American Plate is slowly moving northwest and the Pacific Plate is moving eastward, crashing into it. Twenty-five million years ago, Kelowna and Joe Rich were probably about 500 kilometres south of where they are today in a wet and tropical climate (Were we Americans?), but with the slow northwest drift of the North American Plate, we have ended up where we are today. As the Pacific Plate has crashed into the North American Plate, some of the material of the Pacific Plate has become ‘pasted’ to the west side of the North American Plate. Most of the part of BC west of us is ‘pasted’ material from the Pacific Plate, but here on the east side of Okanagan Lake, we have a mixture of materials from both plates. As the plates have collided, the tremendous forces involved have pushed most of the edge of the Pacific Plate underneath the edge of the North American Plate, but a smaller part of the edge of the Pacific Plate has been pushed across the top of the North American Plate. All along the collision line between the plates, their rock material has folded and cracked throwing up our many ranges of mountains running north and south through BC., and producing valleys between them which were deepened by water erosion.

About 50 million years ago, a large crack developed known as the Okanagan Fault. It is still present today, opening below the east side of Okanagan Lake right under Kelowna and penetrating downward and westward to a depth of 20 kilometres. It runs north and south cradling the lake. Beneath Okanagan Lake, the bedrock forms a deep ‘V’ shaped trough 640 metres below sea level. The difference in elevation between the bedrock at the 2170 foot (784 metre) top of Little White Mountain only a few kilometres away and the bedrock at the bottom of the lake is very great, comparable to the depth of the Grand Canyon in the US. However, the lake bottom does not extend to the bedrock. The valley has been filled in by 750 metres of glacial debris and alluvial silt which lies in the lake bottom.

In addition to the Okanagan Fault, a second smaller crack, the Mission Creek Fault, running northeast to southwest, crosses the Okanagan Fault at Kelowna and passes on to the west. The land north of the Mission Creek Fault has been pushed farther east than the land to the south of the fault. This accounts for the jog in Okanagan Lake from Peachland to the Mission. North of Kelowna, the Okanagan Fault lies more under Woods and Kalamalka Lakes than under the north part of Okanagan Lake. Mission Creek flows down the Mission Creek Fault and Joe Rich lies on top of it. At Layer Cake Hill the rock is 50 million years old, but just across Mission Creek to the south of the fault near the mouth of KLO Creek, the rock is part of the old North American Plate bedrock and is two billion years old.

 

 

 

 

 

 

 

 

2004 Benches in the lower part of Mission Creek Valley

Exploding fire and molten soup

About 20 million years ago, as this part of BC was forced upward, folded and cracked, volcanoes developed in the Kelowna area and continued to be active intermittently for about 10 million years. Black Mountain and Layer Cake Hill were formed at that time. The basaltic lava, which the volcanoes produced, was very liquid and ran out onto plains and into valleys for long distances. Layer Cake Hill is formed by the same eruptions that produced Black Mountain. Its layers may have been caused by successive lava flows or more likely by pressure and heating producing sequential layering of the different substances in the rock. It is unique in the world! Millions of years of river activity had already laid down large deposits of sand and gravel before the volcanoes began to fill the river valleys with lava. At the end of Joe Rich Valley where the road to Big White crosses over the West Kettle River, banks can be seen where lava lies on top of the gravel of the ancient river system which predated the volcanic period.

During the period when volcanoes were erupting around Kelowna, they were also occurring in other areas close by. Ash from larger eruptions sometimes drifted over this area forming thick layer deposits. These ash deposits have formed light coloured layers seen in cut banks in the Philpott Valley. They are probably the result of one of the more recent eruptions that formed Crater Lake in Oregon 6,600 years ago, the Mount Saint Helen eruptions 3,400 and 508 years ago or the eruption of Mount Meager in the Bridge River area 2,400 years ago. At the time of the last eruption of Mount Saint Helen, the wind carried very little ash to this area.

Grinding ice and flowing water

About 1.6 million years ago, the climate began to cool. Ice formed on the high points of land and slowly flowed down into the valleys ripping off protruding bedrock as it flowed. The broken rock was incorporated into the glaciers where it produced a sort of giant sand paper which scoured out the valleys converting their ‘V’ shaped cross section to a ‘U’ shape. A large glacier of this sort flowed down Mission Creek enlarging the valley as it went and carrying millions of tons of rock and gravel into the Rutland and Kelowna area. The Kelowna site started out as a bay in Okanagan Lake and ended up as the area we know today. Several successive glaciers formed over BC and the Okanagan only to recede and then form again. Each ground down the mountains even further. 19,000 years ago, the last glacier, the Fraser Glacier formed and reached its maximum thickness 15,000 years ago when all of BC was covered by ice. This ice reached a thickness of 3 kilometres over the Okanagan Valley and was so heavy that it actually pushed down the land beneath it. Slowly and with some advances and recessions, it began to melt. Ten thousand years ago, it had gone. As it melted, the dark rock of the hills began to protrude through it attracting the heat and producing crevices and wells around them. Gravel and silt were washed into these. Hugh amounts of melt water were formed and flowed down into the valley to produce a massive lake which geologists have named Penticton Lake. It extended from Enderby to below Okanagan Falls and its shore produced beach sand at the edge of Crawford Estates indicating that its surface reached 1,500 feet above sea level. The lake level today is only 1,123 feet. The south end of this lake was the site of a huge ice dam which broke on several occasions releasing gigantic volumes of water producing massive erosion here and in Washington ( Dry Falls and the Columbia Gorge) and lowering the lake level.

During these thousands of years, the ice melt waxed and waned. During a long period of stagnation a large glacier flowed down Mission Creek Valley and produced a huge moraine in Rutland. Some of this still exists as part of the raised land on the south side of Mission Creek southwest of Layer Cake Hill on which McCulloch’s Pub and the surrounding KLO orchards are located. This moraine eventually grew large enough to create a dam which held back the outflow of the very large Mission Creek which developed as the ice began to melt again. This dam produced a long narrow lake which extended up Mission Creek and Belgo Creek Valleys filling Joe Rich with water. Melt water carried rocks, gravel, sand and clay down into the lake adding to the rocky materials the glacier had already left in the area. These forces of ice and water produced most of the geological features of Joe Rich which we know today. A 240 foot deep well which we recently drilled just north of Highway 33 and Three Forks Road passes through 4 feet of organic material and glacial rocks into over 200 feet of pure blue clay and finally reaches a layer of fine sand containing water under enough pressure to rise in the pipe to about 40 feet below the surface. The rocky soil is probably the result of a last gasp of glacial activity and the clay the result of hundreds or thousands of years of fine eroded material being washed into a lake.

As the level of Okanagan Lake has dropped to its present level, Mission Creek has veered to the north and bypassed its old moraine and delta to form what was an alluvial fan of silt which is responsible for most of the topsoil of Kelowna. The creek water erosion continues to deepen Mission Creek Valley and Gallagher’s Canyon and to lay down more and more delta at its mouth, but Mission Creek is now a mere trickle compared to the mighty river it once was when glaciers were melting. In recent history, it meandered through swampy wetlands, but now it has been channelled and its source lakes dammed to insure regular flow and reduce flooding.

Although the silt materials deposited by the rivers and lakes of our area are responsible for the beauty of our landscape, for the forest that grows here, and for the benches characteristic of the Okanagan, they have dangers. On hillsides, streams can undercut them, they can be saturated by water from rain or runoff, or they can be disturbed by the cuts of logging roads or the increased snow melt and reduced stability of clear cut areas. As a result, they are prone to slides.

In October, 1984, a large Earth Slump occurred at the Kelowna end of Bald Range just below Highway 33 and Graceland Ranch. Acres of land slid downhill to obstruct Mission Creek and nearly eliminate the Highway. Silbernagel’s pump house near Mission Creek was buried and they were shocked to wake in the morning, turn on the water, find none and realize what had happened while they slept.

 

 

 

 

 

 

 

 

1984 Earth slump into Mission Creek

On June 12, 1990, a heavy rain and snow runoff which saturated the ground, complicated by clear cut and a logging road triggered a Debris Avalanche which travelled at 10 metres per second over 1.5 kilometres sweeping thousands of tons of mud, rock and trees across Philpott Road to crush and cover Charlie Philpott’s home killing him, his wife, Betty and their daughter, Janet. Other Philpott Road residents were evacuated because of the possibility that more slides could take place on the rain saturated hillside. Both these slides probably involved silt deposits formed at the edge of prehistoric Joe Rich Lake. Similar slides have occurred in the Okanagan Valley and are most common along the clay banks between Summerland and Penticton at the edge of prehistoric Penticton Lake.

The silt banks and delta deposits of Joe Rich and the Okanagan make us vulnerable to earthquakes. The delta plain which forms much of Kelowna would be liquefied by an earthquake of over 7.5 on the Richter scale. However, no earthquakes of over 4.9 Richters have occurred in the recorded history of the Okanagan and are unlikely to do so in the future unless a massive earthquake were to occur off the coast, where the main plate collision is occurring west of Vancouver Island, and the shock were to be transmitted here.

People at last

There is little or no knowledge of the people who may have passed through or lived in prehistoric Joe Rich. A lot of archaeological work remains to be done in BC to uncover such information. However, a few facts give us an idea of what may have happened. Human beings appear to have entered North America across an ice bridge or land connection between Asia and North America at the Bering Strait less than 20,000 years ago. Most of them were probably driven south quite quickly by the cold and did not return to BC until the end of the last ice age about 9,000 years ago although they would probably already have been present in Washington and Oregon 10,000 years ago, when the wall of water surged south released by the failure of the ice dam at the south end of Penticton Lake. A horrible thought!

By 3,000 years ago, there were probably more than 12,000 people living in the Okanagan as hunter-gatherers. They lived in pit houses constructed over a large flat bottomed excavation, about a metre deep, covered by a low-profile, tepee-shaped roof topped with earth and constructed of poles and branches with a hole in the top for the escape of smoke. In the summer, they lived more nomadic lives and probably carried woven tulle mats with them which they used for temporary shelters. They had no horses until 1730, but perhaps used dogs which may have pulled travois. They dug up bitterroot and balsam root which they roasted in pits before eating. They hunted bear, elk, deer, moose, mountain goat and in the winter, sheep. When the snow was crusted enough for them to run on top, they very successfully hunted the deer that sunk through the crust and quickly tired. But a large part of the Okanagan Salish diet was always fish and mainly salmon. The salmon came up the river past Okanagan Falls each October, and the native people met there to fish and prepare the catch for winter storage. This was always a happy meeting time for almost the entire population; a time when many marriages occurred. Almost certainly, some of these people hunted and trapped in Joe Rich. Perhaps some may have lived here during their summer travels in search of game. Probably none stayed the winter.

This rhythm of life appears to have continued until Alexander Ross, a fur trader came up the Okanagan through Penticton about 1910, and Father Pandosy came to stay and preach to the native people in 1859.

 

 

 

 

 

 

 

 

2004 Earth Slump below Highway 33