Geos 100 Camosun College: Local Victoria Area Field Trip Dr. T.S. Hamilton. F13
Leave Campus and head East on Lansdowne and south on Beach Drive to Cattle Point.
Enter at south end and meet in north parking lot by boat ramp (not Willows Beach end)
1) Cattle Point – Geology to observe
a) Glaciated metamorphic bedrock of Lower Paleozoic Colquitz Gneiss makes the hill
and beach front outcrops. Note fracturing, jointing and faulting in bedrock. Note light
(quartz and feldspar) and dark (amphibole and mica) bands in gneiss. Note structures
like foliation, folding, faulting. Note wet-based sub glacial flutes and scours.
b) As defined by Jan Muller, Colquitz is a "quartz-feldspar gneiss" often foliated and the
Wark is a "massive and gneissic metadiorite, metagabbro, and amphibolite". Here
there are massive non-foliated quartzofeldspathic gneisses north and south of the 2
boat ramps and foliated metavolcanics and metasediments on the low beach East of
the parking lot in between.
c) Note modern beaches and sediments: sand, gravel, cobbles, logs, shells. Note sorting
by size and relationship to shoreline and sea level.
d) Note man made fill beneath parking lot. The sequence oldest to youngest: a, b, c
e) Look off to Cascades the modern volcanic arc, Haro Strait as a glacial fjord and see
Cattle Point and San Juan Islands as the mid crustal metamorphic roots of an eroded
mountain belt.
2) Drive S and West to Harling Point and meet at West edge of Chinese Cemetery.
a) Note Olympic mountain uplift rising at >1 cm per year made of 55 Ma seafloor
b) Note McLaughlin ridge formation marine siltstones in tide zone and ribbon cherts
above cemetery. Probable Paleozoic or Triassic age.
c) Note fluting of wet based glacier in bedrock.
d) Note veining and intense clay and hydrothermal alteration of bedrock. This likely
happened as water escaped upwards from underlying Olympic terrane seafloor (=
to Sooke and Metchosin) through the older upper plate rocks of the McL Ridge.
You are standing on a thrust fault & a probable fossil subduction zone from
45Ma.
3) Drive to Dallas Road past Clover Point Outfall, near Finlayson Point and park.
Look at eroded cliffs, modern beach and bedrock at Finlayson Point.
a) Look at the eroded cliff face. Note glacial marine sediments, soft unconsolidated
yet stiff and compacted. There are unsorted ice deposited layers with everything
from cobbles to clays and other water lain layers in lenses that are sorted sands
and gravels likely in front of or beneath a floating ice shelf.
b) Note modern beach: sands, gravels, cobbles, sedimentary bedforms. Compare
grain size to wave energy and direction of current.
c) Walk west as permitted to Finlayson Point and assemble on bedrock of Tyee
granite. Note cross cutting igneous dykes and inclusions of older metamorphics.
d) Note erosion on this “nonconformity” where all of geological time between Upper
Devonian and Late Pleistocene is missing or removed by erosion.
e) Note the till – boulder clay of the cliff and overlying terrace. Compare the
boulders to the cobble beach to the East. Where did those cobbles come from?
Were they transported there or left behind as everything else was transported
away?
Questions – see other side of sheet!
Questions: Lab Section: 1=Wed or 2=Thurs
Name _______________________
Cattle Point:
1. What was the direction of the maximum compressive force that deformed the
gneisses?
A) North-South B) East-West
2. What were the original rock types for the thinly foliated dark and light Wark
Gneiss in the foreshore intertidal zone?
A) Sedimentary and Volcanic Rocks
B) Plutonic igneous rocks
3. What was the highest grade (T°C) metamorphic mineral found in the dark bands?
A) Biotite
B) Hornblende
Harling Point:
4. Name 2 original sediment types and describe their environment of deposition?
A) Limestone and sandstone, warm tropical shallow water near shore
B) Siltstone/Shale and Chert, cold deep water, offshore
5. What caused the smooth troughs in the rocks on the foreshore?
A) Chemical weathering by seawater
B) Hydraulic fluting at the base of a wet glacier
6. What is the big rock in the intertidal zone and how did it get there?
A) A piece of schist that tumbled downhill during a major earthquake
B) A piece of granodiorite that was ice rafted debris from the Coast Mountains
Finlayson Point
7. What kind of material forms the wave cut cliffs along the Dallas Road waterfront?
A) Metamorphic Rocks of the Wark Gneiss, similar to Cattle Point
B) Glacio-marine Sediments deposited below sea level containing dropstones, rock
flour and clam shells
8. How does the particle size vary along the beach and why?
A) Biggest to the East as brought in by a west flowing glacier
B) Biggest to the West as a lag from the east directed longshore drift
9. What are the oldest rock types in the Tyee Pluton at Finlayson Point and why?
A) the white ones because they melt first
B) the black ones because they are cut by and included in the white ones