Field Trip to Millstream River

Swirling river undercutting rock

November 10, 2011 - This field trip was undertaken to examine the workings of the river, in all it's aspects, i.e. to identify various formations, surficial materials, fluvial features, and describe current and anticipated human impacts on river flow, vegetation, slopes, and soils.

 

Sedimentary Rock / Alluvium

• Siltstone
• Sandstone
• Conglomerate

Alluvium environment with a mix of different textures; laid down by the river; unconsolidated materials.

Mass Wastage

• Undercutting of steep slopes
• Slumps or mass wastage – occurs at a couple of places along the Millstone



Movement occurs downhill as waterfalls

• Movement occurs downslope under the influence of gravity

Glacial Debris

• Glacial till covers much of the underlying bedrock
• Visible in the more elevated wooded areas – away from the Millstone
• Debris near the Millstone has been reworked by the flow of running water

Tumbled rock

 Altered Flow of Millstone River - Natural Processes

• Faulting and fissuring of bedrock
• River channels flow in straighter lines (structural control)
• Provides sharp elevation differences (i.e. waterfalls)
• Volume and velocity of water flow changes with the seasons
• Material carried in suspension or moved via saltation processes further erodes, by abrasion, additional material
• River banks can be undercut, trees toppled (often with assistance of wind)
• Soils and blocks of bedrock can tumble into the channel

Salmon ladder

Altered Flow of Millstone River - Human Impacts

• Construction of roads, trails, parking lots, bridges, and so on, impact rate and volume of flow into the river
• Runoff is accelerated and volume of interflow is lessened with development of impermeable surfaces
• Construction of weirs has impacts the holding back flow of water
• Construction of a fish ladder has diverted some of the flow into an artificial channel

Seasonal Variations

• Volume of water flowing down Millstone River is greater in the winter months when Nanaimo receives most of its precipitation and the temperatures are cooler (less evapotranspiration)
• Volume is less in the summer when the weather is warm and dry (greater evapotranspiration)
• Evidence of this is the scoured bedrock from flooding in winter
• Pothole development (abrasion during flood stage of the river)

Undercut bedrock, potholes

Natural Processes along the Millstone

• Tectonic activity – shift in the plates causes fracturing and fissuring of underlying bedrock
• Undercutting of the river in the cutbank slopes of the valley which leads to mass wastage or slumping
• Evidence: fallen trees, slumping of soil and bedrock which is aided by gravity

Swollen river flowing past my Prof.

The Ocean

“The edge of the sea is a strange and beautiful place.” ― Rachel Carson

... and a place of dynamic change.

  

Chemical Composition of Seawater & Ocean Chemistry

• water is the "universal solvent" dissolving at least 57 of the 92 elements found in nature.
• most natural elements and the compounds they form are found in the seas as dissolved solids, or solutes.
• seawater = solution/concentration of dissolved solids = salinity
• oceans remain homogenous mixture = ratio of individual salts remain unchanged, despite minor fluctuations in overall salinity.
• ocean chemistry = complex exchanges of seawater, the atmosphere, minerals, bottom sediments, and living organisms.
• mineral-rich water enter the ocean through hydrothermal (hot water) vents in the ocean floor.
• uniformity of seawater = complementary chemical reactions and continuous mixing - ocean basins interconnect, and water circulates among them.
• seven elements account for more than 99% of the dissolved solids in seawater =  chlorine, sodium, magnesium, sulphur, calcium, potassium, and bromine.
• seawater also contain dissolved gases = carbon dioxide, nitrogen, and oxygen.  Also contain suspended and dissolved organic matter, and a multitude of trace elements.
• Average salinity - 3.5% (% parts per hundred) / worldwide 3.4% to 3.7%, attributable to atmospheric conditions above the water and to volume of freshwater inflows.

Final Geography Exam - Dec. 14, 2011

Next week is the last Geography exam.  It will cover chapters 16 to 18.  Chapter 16 is on The Oceans, Coastal Processes, and Landforms, Chapter 17 on Glacial and Periglacial Processes and Landforms, and Chapter 18 The Geography of Soils.

I hope I do reasonably well, since I've not been doing so thus far.  The lab exam marks are out, but I'm too nervous to check.  Weird, hey!  But, I am just hoping for a C, C-?  This course has battered me, and lowered my confidence in taking science courses.   But, I do love the geographical sciences.

Oh well ... onwards!  I'll not let a challenge go unfought (is that a word).

Kepler Mission - A Feature Article in progress

This is a feature article I am writing for my creative writing course.  It is still in the draft stage, but I feel good enough for my "Earth and the Universe" blog. 

MOVED TO MY 'SPACED OUT' BLOG.

Finding one's way on the map

I am finally getting the UTM and longitude/latitude co-ordinating.  I just couldn't get how it worked for the longest time.  And, I need it for lab exams.  So, yay for me. :D

Weathering

If one could speed up the Earth, in time, one would see mountains forming, then breaking down to bedrock, minerals dissolving in water, and reassembling by chemical processes to mineral then rocks.  Landforms would be undergoing a continual movement of growth and denudation.  This denudation is a process of wearing away or rearranging landforms.  A constant upward, downwards, and sideways motion would be observed - the planet moving to the  song of weathering, mass movement, erosion, transportation, and deposition, sung by moving water, air, waves, ice - the strings plucked by gravity.  All notes rushing toward equilibrium --> imbalance --> equilibrium .  The geomorphic threshold "is the point at which there is enough energy to overcome resistance to movement" - a seesaw between exogenic/endogenic events and the trend toward equilibrium.  The constant weathering of the upper surface of bedrock creates broken-up rock, is called regolith. 

Some of my Notes from class:

Definition of weathering:  The breaking down of rocks into mineral particles by mechanical means, or by dissolving in water.

Physical Weathering

• Making little rocks from big rocks – a mechanical process
• Process exposes more rock mass for additional weathering – both physical and chemical

Types of physical weathering:

• Frost Action
• Crystallization
• Pressure-Release Jointing
• Biological

Biological Weathering

1. Roots – growth in crack and fissures → break up of rock
2. Bioturbation – mixing of soil by worms (earthworms) and burrowing animals (gophers)
3. Chelation – alternative wet and dry lichen activity (algae and fungi) on exposed bedrock (Canadian Shield) → disintegration of the rock
4. Humans

Chemical Weathering

Chemical weathering – decomposition of minerals in rock – involves reactions between air and water and minerals in rocks.

• Minerals combine with oxygen or carbon dioxide from atmosphere → dissolve and combine with water
• Water is abundant – has incredible ability to dissolve matter

Chemical Rock Weathering

Rocks can be chemically altered, for example:

Granite

Quartz minerals in granite more resistant to chemical weathering than feldspar → clay

Limestone

Rock enters into solution → washes away

Types of chemical weathering:

• Hydration and Hydrolysis
• Oxidation
• Carbonation and Solution
• Biological

 Formation of Karst  

• Limestone / dolomite bedrock formations develop into karst topography if the following conditions are met:
• At least 80% of formation composed of calcium carbonate materials
• Formations are jointed
• Formations are aerated
• Vegetation available to provide organic acids - enhances solution processes
• Features include: Subsurface channels, sinkholes, caverns, and steep slopes

 Sources: Wikapedia
Canadian Geosystems, Christopherson/Byrne

In the Beginning

As a writer, I feel I have to know stuff, so I have taken a course in Earth Environments, which is an introductory course in geography.  I have always been interested in the earth sciences and astronomy (my favourite genre to read is Sci-fi).  So, I am going to attempt to delve into the science of the earth and the rest of the universe.  I will start with my class studies, and take that path wherever it may lead, hoping to improve my test scores, but also my general knowledge of what is under our feet, all around us, and beyond.

Columbia River Gorge just east of Portland, OR. I am fascinated by the history/science behind what created this environment.  More on this later.