Be the Block: The Geologic Block Diagram as an Inquiry Tool

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Be the BlockThe Geologic Block Diagram as an
Inquiry Tool

• Eric J. Pyle
• James Madison University
• pyleej_at_jmu.edu
• With support from Lynn S. Fichter, JMU

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Nicolas Steno Principles
Steno established several principles about the
origin and interpretation of rocks. These are
still the foundation of all geological studies.
They are stated below in their modern wording.
Steno expressed these ideas in what would be for
us more arcane and florid language.
1. Principle of Superposition rock layers on
the bottom are deposited first and are the
oldest those on top are deposited last and are
the youngest.
2. Principle of Original Horizontality rocks
are deposited horizontally. Rocks that are no
longer horizontal have been displaced from their
original positions by later events.
3. Principle of Lateral Continuity identical
rocks that are now separated at one time must
have been connected and continuous.
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A trip back 200 years

• The rocks of England
• The fossils in those rocks
• How do these relate to the geology we see and
  seek?

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18th Century Crises

• Energy Crisis - fueling the factories
• Deforestation removed wood as fuel
• Large amounts of coal were available
• Transportation Crisis - fuel to where it was
  needed
• Coal was not always where the factories were
• Roads were small and terrible
• Food Crisis - fueling the factory workers
• Small freehold farms were not very efficient
• Much of the population had moved to urban areas

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18th Century CrisesSolutions

• Energy Crisis - promote the expansion of coal
• mining
• Transportation Crisis - promote the
• development of canals
• Food Crisis - Acts of Enclosure and expansion
• of water meadows
• Each solution required geological and
  geotechnical expertise

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In eighteenth century Britain it was a mark of
refinement and impeccable good taste to own and
display a collection of fossils. . . .
Not only were the objects themselves rare and
beautiful, well worthy of display in specially
constructed glass cabinets the simple possession
of them hinted at a thirst for knowledge, an
awareness of natural philosophy, a sympathetic
understanding of the mysterious processes of the
earth.
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Types of Mines
Drift Mine - cut into the side of a hill into
horizontal strata.
Shaft Mine - vertical tunnel dug to deep
horizontal or angled strata.
Slope Mine - inclined tunnel dug to relatively
shallow layers.
http//66.113.204.26/mining/coal/undergnd_mining.h
tm
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Money to be made
Anybody that owned land wanted to know if there
was coal beneath the surface. Overhead costs,
including worker safety and working conditions,
were to be kept at an absolute minimum.
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The Mearns Coal Pit in Somerset, England
For the Mearns Pit at High Littleton has a
standing in the history of geology that is
comparable to the one that Gregor Mendel's
Moravian pea garden has in the science of
genetics, the Galapagos Islands in evolutionary
theory, and the University of Chicago football
stadium in the story of nuclear fission.
View into Somerset from Chedington
Yet this Somerset coal mine also goes
unremembered today, just like Rugborne Farm.
There is no blue plaque, no brass plate, nothing.
Just a small lump in a field that marks a
scarified hillock of grassed-over mining waste, a
mound that Somerset people still call a batch.
And a scrap of paper in the University Museum in
Oxford, recording what William Smith saw, felt,
thought, and concluded when first he ventured
into the dripping darkness of that dreary little
West Country colliery.
http//www.britainexpress.com/countryside/dorset/c
hedington-p2.htm
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http//www.durhamrecordsonline.com/literature/coal
fields-british.gif
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Getting fuel and food to where it was needed
Another money-making scheme was to build canals
to take coal and food to industrial centers.
There was very little government funding for
these operations. Costs were underwritten by
wealthy investors and individual stock
subscriptions.
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Getting fuel and food to where it was needed
Canal building required extensive surveying work
along with excavation of watercourses and
tunnels, as well as building aqueducts.
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Somerset Coal Canal
Map shows the two near-parallel branches of the
Somerset canal that later helped Smith in
confirming his theories about how rocks were
distributed in the Earth.
The entrance to the former Somerset Coal Canal at
the Dundas Aqueduct.
http//www.redadmiral.freeserve.co.uk/canalling.ht
m
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Scenes of the Somerset Coal Canal where William
Smith Worked Out His Stratigraphy
I observed a variation of the strata on the
same line of level, and found that the Lias rock
which about three miles back was a full 300 feet
above this line was now 30 feet below it, and
became the bed of a river, and did not appear any
more at the surface," This induced me to
note the inclination of the same rock, which I
knew was to be found at the head of two other
valleys lying each about a mile distant from, and
in a parallel direction to the one Just described
and accordingly found it to dip to the
south-east, and sink under the rivers in a
similar manner.
Dundus Aquaduct
From this I began to consider that other strata
might also have the same general inclination as
well as this. By tracing them through the country
some miles I found the inclination of every bed
to be nearly the same as the Lias and
not-withstanding the partial and local dips of
many quarries which varied from this rule, I was
thoroughly satisfied by these observations that
everything had a general tendency to the
south-east and that there could be none of these
beds to the north-west.
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http//www.durhamrecordsonline.com/literature/coal
fields-british.gif
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http//www.rod.beavon.clara.net/canals.htm
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Acts of Enclosure
Land that was previously held in common for
animal grazing, or land occupied by small tenant
farm operations, was turned over to the control
of large landowners for their use in agricultural
production. Agricultural production increased
dramatically, but tenant farmers were turned out
of their farms and forced to work in mines and
factories.
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Acts of Enclosure
Land that was previously held in common for
animal grazing, or land occupied by small tenant
farm operations, was turned over to the control
of large landowners for their use in agricultural
production. Agricultural production increased
dramatically, but tenant farmers were turned out
of their farms and forced to work in mines and
factories.
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Water Meadows and field rejuvenation
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William Smiths Geologic Map of Great Britain
http//www.geolsoc.org.uk/template.cfm?nameSmithM
ap
http//www.ethicalatheist.com/img/william_smith_ma
p_big.jpg
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http//www.coastalguide.org/england/figure2.gif
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The Geologic Map as Inquiry

• Simple Explanation of Smiths work
• Observed rocks and fossils
• Predicted locations
• Verified/tested predictions
• Inferred extent
• Complex Explanation
• Applied Inquiry techniques

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Defining Questions
Choosing Methods
Arriving at Solutions
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• Engagement students are asked to reflect on
  their prior knowledge of Stenos Principles as
  well as the social, scientific, and technological
  climate of the late 18th and early 19th Century
  England. A few slides about Steno and the
  industrial age crises in England are presented.

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• Exploration placed around the room are a series
  of stratigraphic columns and surface expressions,
  with lithologies represented by different colored
  squares of construction paper. Some of these have
  overprinted on them sedimentary structures or
  fossils. The columns are placed in such a manner
  as to represent the corners and the middle of the
  sides of a block diagram, rendered flat as a
  cut-out and foldable object. Students then plot
  the lithologies in order on the block, connecting
  similar lithologies to reveal not just the
  cross-sections but also the surface expression.
  The block is then cut-out and folded into the
  standard block diagram.

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• Explanation the structures created by the
  students are evaluated compared to a master block
  diagram and corrections made. The remainder of
  the slide presentation is shared, relating the
  development of the geologic map by William Smith
  and its basis in his observations of coal mine
  shafts, canal excavations, and related fossils.

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• Elaboration Students are given additional block
  diagrams, containing only partial information,
  and asked to infer what would exist in the blank
  areas.
• Evaluation students are given a complete block
  with more complex structures and asked to design,
  through inference, a set of columns and surface
  expressions that would represent the diagram and
  allow another student to recreate the structures.

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