ROCKS - Key 2013
Tasks:
1. Explain the underlined words. Use their synonyms, formulas, or describe them.
(merely, tan, dilute, vinegar, hydrochloric acid)
merely = only, tan = light brown, vinegar = liquid made from grapes to add a sour taste(like
lemon), HCl
2. Find the synonym for the word immediately in the last paragraph. - readily
3. What are the two most important physical properties to look at when identifying a rock?
color and hardness
4. How can you distinguish calcite from quartz in rocks?
calcite has a hardness of 3, while quartz has a hardness of 7; calcite bubbles in HCl
LISTENING
Geologists say they have discovered some rocks in Canada that may be the oldest rock on
Earth.
Task: Listen to an interview with a geologist J. O´Neil and answer the questions.
You will find the mp3 file in the syllabus in IS.
1) How old is the Earth supposed to be?
- 4.6 billion years
2) Why is it not easy to find the rock as old as that?- the earth surface is constantly changing
3) Where has the previously oldest-known rock that is thought to be 4 billion years old been found?
- (Acasta Gneiss) in Canada´s Northwest Territories’
4) Do you know how the scientists determined (establish) the age of ancient rocks in the
past?
- by looking at the composition of zircons. The age of such grains that have been
found is 4.36, but the rock that was originally around these grains has eroded away.
5) Which university is a geologist Jonathan O´Neil at? What level is he?
- a PhD. student at McGill Univ. in Montreal
6) What reaction on the finding of the oldest rock did a geologist Jonathan O´Neil suppose? contraversy: some scientists will question the claim.
7) Where did he find the rock which he believes that might be the world´s oldest?
- on the eastern shore of Hudson Bay in Quebec
8) How does he get there? - He has to take a plane up to a remote village, then he takes a
canoe down the Hudson Bay to a spot in the tundra where the flat rock is exposed
9) How old is the rock he found there supposed to be? - 4.3 billion
10) Where did O´Neil and his colleagues present his evidence? - in journal Science
11) Why did O´Neil not use the “zircon technique” which was used until then?
- Because his rock did not have any zircon grains.
12. What was his technique formally (previously) used for? - for dating meteorites
13) What may the finding of the earliest rock bring to science?
- to understand the beginnings of life on Eearth
ÚPRAVY A DODATKY V ps 2014:
Rock cycle (added at the end of the text):
Sandstone began as large deposits of beach or river sands that were later compacted
and lithified (“turned into stone”). The grains of sand of which sandstone is composed
is the mineral quartz (SiO2). The quartz grains came from the weathering and erosion
of igneous rocks, particularly granite, that have high amounts of quartz (granite is an
intrusive igneous rock composed of feldspar, quartz and biotite mica).
Task: a) Find the opposites of together b) Find the synonyms of transported to depth solidify changed by heat from a solid to a liquid turned into stone -
, soften , lifted -
, buried ,
Task: Look at the slide describing the rock cycle and explain the changes.
The mineral composition of a rock. Recognizing a few basic minerals will help you
to make an approximate identification, which is sometimes all that a person can make
without special equipment.
For a rock to be given a name, it must contain an essential mineral, if only in small
amounts, e.g. quartz and alkali feldspar are essential minerals in granite. Some rocks
are monomineralic. On the other hand, an accessory mineral does not affect the
name given to an igneous rock. (Longman Dict.)
Fill in the missing gaps:
Sandstone is a sedimentary rock ______________ of mostly of quartz sand, but it can
also contain significant ___________ of feldspar, and sometimes silt and _________.
Sandstone that contains more than 90% quartz is called quartzose sandstone. When
the sandstone contains more than 25% feldspar, it is called arkose or arkosic
sandstone. When there is a significant amount of clay or silt, geologists _________ to
the rock as argillaceous sandstone. Argillaceous sandstones are often gray to blue
and ______________ are referred to as bluestone. Because it is composed of light
colored minerals, sandstone is typically light ____________ in color. Other elements,
_____________, create colors in sandstone. The most common sandstones have
_____________ shades of red, caused by iron oxide (___________). In some
instances, there is a purple hue caused by manganese.
Sandstone is a sedimentary rock composed of mostly of quartz sand, but it can also
contain significant amounts of feldspar, and sometimes silt and clay.
Sandstone that contains more than 90% quartz is called quartzose sandstone. When
the sandstone contains more than 25% feldspar, it is called arkose or arkosic
sandstone. When there is a significant amount of clay or silt, geologists refer to the
rock as argillaceous sandstone. Argillaceous sandstones are often gray to blue and
consequently are referred to as bluestone. Because it is composed of light colored
minerals, sandstone is typically light tan in color. Other elements, however, create
colors in sandstone. The most common sandstones have various shades of red,
caused by iron oxide (rust). In some instances, there is a purple hue caused by
manganese.
from MEC for listening - credit G1
Background: Sandstone is a sedimentary rock composed of mostly of quartz sand, but
it can also contain significant amounts of feldspar, and sometimes silt and clay.
Sandstone that contains more than 90% quartz is called quartzose sandstone. When
the sandstone contains more than 25% feldspar, it is called arkose or arkosic
sandstone. When there is a significant amount of clay or silt, geologists refer to the
rock as argillaceous sandstone. Argillaceous sandstones are often gray to blue and
consequently are referred to as bluestone. Because it is composed of light colored
minerals, sandstone is typically light tan in color. Other elements, however, create
colors in sandstone. The most common sandstones have various shades of red,
caused by iron oxide (rust). In some instances, there is a purple hue caused by
manganese.
LISTENING - an interview with a geologist J. O´Neil about the oldest rock.
The link to Mp3 file is in the syllabus in IS. Try to answer these questions:
1) How old is the Earth supposed to be?
2) Why is it not easy to find the rock as old as that?
3) Where has the previously oldest-known rock that is thought to be 4 billion years
old been found?
4) Which university is a geologist Jonathan O´Neil at?
5) What level is he? (Bachelor / Master / PhD)
6) In which part of Canada did he find the rock which he believes that might be the
world´s oldest?
7) How did he get there?
8) How old is the rock he found there supposed to be?
9) Where did O´Neil and his colleagues present his evidence?
10) What was his technique of dating the rock formally used for?
11) What may the finding of the earliest rock bring to science?