EOCENE VANCOUVER: Kitsilano Foreshore

 

Location ID: 20-LM-GT1

Sand Ripples

As you get onto the beach you will see several large, flat topped blocks of sandstone. The tops of these have an interesting mottled texture - these are actually 'fossilized' sand ripples, much like we find on the beach today. 

The shape of the sand ripples tell us that the water was flowing in one direction, so these could have been made by water flowing out of a river an into the marshland that existed here over 30 million years ago.

Beach Access Point

Access to and from the beach from the pathway by Kitsilano Yacht Club. The path is made of gravel and a few small steps down to the shore. There is no hand rail so be careful not to slip on the loose chips!

Beach Access Point

A series of steps lead to the beach from the end of the footpath. Note there has been a large stump in front of these steps for many years which can obscure them!

A River In Flood?

This is a really interesting part of the beach as it preserves a dynamic moment of time from millions of years ago. This spot is on the western bank of an old river ("paleochannel") and you can see the line of the river bed sweeping up the low cliff to the old river bank. There are large blocks of muddy material within sand at the bottom of the channel, and these were chunks of the old river bed or bank that were torn away by water and redeposited. These features are called "rip up clasts". You will also notice thin black layers - these are small lenses of coal that would have originally been plant debris that got buried in the river sediments.

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Beach Access

The path here has a few steps up and then passes through Volunteer Park which connects to Point Grey Road.

Beach Access

These are a steep set of stairs adjacent to a storm water drain. These lead up to an alley at the junction of Point Grey Road and Balaclava Street.

Volcanic Dyke

This is a great location to see a volcanic dyke - a feature that once would have been a crack in the ground filled with basaltic magma. If you follow this one up the beach, you will see that it splits as the molten rock was squeezed through different cracks in the ground!

Volcanic Dyke

This is a great location to see a volcanic dyke - a feature that once would have been a crack in the ground filled with basaltic magma. The heat from the magma 'cooked' the sands and made them harder and therefore more resistant to erosion. You can see this today as this feature sits about one meter above the beach level.

Leaf Fossils

This section of beach is very flat and at low tides you might see some clay layers exposed. You cannot dig for the fossils here, but keep a look out for blocks of clay that wash out (especially after winter storms!) and you may get lucky enough to find some fossilized leaves!

Beach Access

The stairs here are steep and are uneven due to slumping cliffs, so care is advised when using them! At the top of the stairs, you can either turn left to the Point Grey Road / Dunbar Street junction, or go straight on down Cameron Avenue which will bring you out at Hastings Mill Park.

Tree Trunks

The discovery of these preserved tree trunks was made in 2020, and is proof that the beach can yield new sites all the time! In this area, three relatively large tree trunks are preserved, with some wood remaining and the core of the trees replaced by hard sandstone. These were likely to have been washed up on the ancient shoreline over 30 million years ago and buried in sediments, much like we see happening to modern drift wood on the beach today.

Fossil Leaves and Reeds

At this location you can sometimes find blocks of mud with plant fossils. The most common leaves are broad leaf deciduous trees, such as sycamore or birch, but we also find reeds which suggest thick marshy growth around wet ground where other leaves would blow or wash in. 

BC Hydro Geotechnical Borehole: BH19-03

 

Borehole for the new substation at Nelson Park in the West End of Vancouver which recovered material from the Kitsilano Formation under the downtown core. 

Click here to see a Gigapan image of the core

Trafalgar Street Section: Cross Bedded Sands

Margaret Piggot Park Paleochannel

 

 

Kitsilano Geology

 

The Kitsilano Foreshore is an excellent location to view the geology of the Vancouver area. The low cliffs along the shore show layers of rocks that were deposited in ancient river channels, and low tides reveal flat beds of mud and clay that preserve fossil plant remains and thin seams of coal.

 

The Kitsilano Formation

 

The rocks and sediments exposed are part of the Kitsilano Formation, which is the upper of two continental sedimentary formations which dominate the local geology. These layers are tilted at about 10 degrees to the northwest into the Whatcom Basin, a topographic and structural low that is about 75 kilometres across (stretching from the Coast Mountains north or Vancouver to Bellingham in the south). The sediments that create the rocks here were deposited in the late Eocene or possibly early Oligocene, so about 40 million years ago.

The layers are around 760m thick, so what we see exposed on the shore is only around 1% of the total formation. The very lowest part of the Kitsilano Formation was observed by the Second Narrows Bridge and consisted of imbricated conglomerates which suggested a westerly flowing river. The primary rock type are coarse-grained sandstone which are often cross-bedded and occasionally contain small lenses of lignitc coals. Shales are also common and preserve fossil leaves.

 

 

The Plants of the Kitsilano Formation

 

Fossilized remains of leaves and pollen are common in the Kitsilano Formation. Formal papers on this site have not been written since the 1960’s, but in that work many recognizable species were named. The gallery below shows some of the key species found in the foreshore deposits.

 

The Ancient Environment

 

Fossil evidence can be used to help determine what the ancient environment was like. Plants are especially good indicators as, unlike animals, they cannot migrate with changing conditions and so tend to die off and get replaced by more suitable species in that area. 

Modern species of the plant assemblage tend to live in warm temperate to subtropical areas. Many of the species are found today in low ground which is moist and poorly drained coastal areas. Others exist in ponds or lakes indicating standing water.

Other plants, such as the pines and oaks, would prefer higher and drier ground, and so were likely not living in this area, but their leaves were being transported by rivers along with the sediments and getting buried and preserved. They could have been living on the edges of the Whatcom Basin to the north, east or south of the modern foreshore.

The rocks and sediments we find on the foreshore suggest a terrestrial environment passing into shallow water, such as a river mouth where there were multiple stream channels passing over a sandy alluvial plain, with quiet lagoonal, pond or marshy zones where mud could accumulate, passing into more sandy deltaic zones, perhaps looking something like the image below:

 

Taxodium sp. trees with ferns in a drier forest setting with low lying shrubs, broad leaf trees and other vegetation (photo credit University of Delaware)

 

Hotspots Background

Quiet Lagoon

This type of environment would allow for mud and silt to build up in quiet water conditions. There would be plenty of organic material buried within the layers from the surrounding wetlands and marshes.

Beached Logs

Tree trunks that get washed out of the forest and along the rivers tend to get stranded on sandbars, beaches and other areas of shallow water.

Cross Bedded Sand

The main outflows of the river would continuously dump and rework sand at the mouth. These bodies of sand migrated resulting in cross bedding structures. 

Rippled Sands

Water flowing in a shallow channel into a deeper body of water allows for the formation of ripple structures. The dominant water flow is from the river which creates asymmetrical ripples. 

Saturated Soil Forests

Around the margins of the rivers would be areas of wet, poorly drained soil that was prone to flooding. Ferns and cypress trees would have flourished in these conditions.

Higher Elevation Forests

Higher ground would be occupied by plants that preferred drier soil conditions, such as oaks and pines. When the trees shed their leaves in the fall, some of these leaves would have been washed into rivers and buried in the shallow lagoonal areas.

Primary Channels

Wide rivers cut through the landscape, scouring into the bedrock to create u-shaped channel profiles. These erode the banks of the river and rafts of vegetation fall in and get buried in sediments. Occasional flood events would add additional energy that ripped up chunks of the bed and deposited them in the sands. 

 

The Mystery of the Missing Animals

One of the mysteries of the Kitsilano Foreshore deposits is that, so far, no animal fossils have been found. This is unusual for several reasons:

1) The environment was productive and would have supported a wide variety of animal life, from fish to insects and even small mammals.

2) Leaves only preserve under very special circumstances, such as rapid burial, fine sediments and anoxic conditions. Teeth, bones and insects are much more resilient than plant matter and so would usually preserve well

3) Other similar deposits in British Columbia such as the Cache Creek (McAbee) Fossil Beds produce fossil plants and animals in layers of mud and silt. 

We do think we have found evidence of animals in the form of “leaf mines” where a mite or some other plant eating animal grazed on broad deciduous leaves.

So why do we think we have not found any animal fossils? It is likely down to the ‘sampling size’ of specimens collected from the foreshore. The leaf-bearing layers are restricted in size and collection is from loose blocks. These layers are also thin and inter-bedded with the sandstone, which is much less likely to preserve animal remains due to the coarse grain size, high energy deposition and acidic nature that can dissolve organic material upon burial.

Many of the animals we would expect such as freshwater fish and flying insects such as mayflies could be so mixed with the leaves that they are hard to distinguish.

Finding animal fossils on the Kitsilano Foreshore would be an important discovery and we hope that one day soon they will be found!

Large ant fossil from the McAbee Fossil Beds (photo credit Simon Fraser University)

The foreshore at Kitsilano represents a great location to explore the geology of the Vancouver area, with many types of geology and even fossils exposed in the low cliffs and outcrops. 

The map shows key locations and provides links to additional information.

 

Virtual Field School

 

Below BC has built up a range of data and virtual experiences for this site that can be used for teaching geological basics. Please refer to the sections below the map for full details.

 

Resources

 

Use the links below to access more information for class exercises, data and other useful information.

Data Sets

Field Data: Excel spreadsheet of all field data points (Last updated 15th May 2020)

Drill Data: Basic downhole information from BC Hydro drilling at Nelson Park, West End Vancouver

Base Maps

Basemaps: Series of blank maps of the foreshore for students to plot data

Sample Images

Rock Chips: Images of representative rock chips listed in the Field Data Sheet

Fossil Material: Images of fossils collected from the foreshore

Interactive Imagery

Paleochannel Slider: Further information about the channel sections

Drill Core

The following material refers to geotechnical data donated to Below BC by BC Hydro. The drilling took place in Nelson Park, West End area of Vancouver.

Reference Material

Palynology Paper: Palynology of the Eocene Kitsilano Formation, sw British Columbia (Hopkins, 1969)

Collection of Fossils: The button below links to the Provincial laws and regulations governing the collection and use of fossil material. We encourage all users to familiarize themselves with these guidelines!

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