MS2
£2.00
WELSH JOINT EDUCATION COMMITTEE
CYD-BWYLLGOR ADDYSG CYMRU
General Certificate of Education
Tystysgrif Addysg Gyffredinol
MARKING SCHEMES
JANUARY 2006
AS/Advanced
GEOLOGY
INTRODUCTION
The marking schemes which follow were those used by the WJEC for the January 2006
examination in GCE Geology. They were finalised after detailed discussion at examiners'
conferences by all the examiners involved in the assessment. The conferences were held
shortly after the papers were taken so that reference could be made to the full range of
candidates' responses, with photocopied scripts forming the basis of discussion. The aim of
the conferences was to ensure that the marking schemes were interpreted and applied in the
same way by all examiners.
It is hoped that this information will be of assistance to centres but it is recognised at the
same time that, without the benefit of participation in the examiners' conferences, teachers
may have different views on certain matters of detail or interpretation.
The WJEC regrets that it cannot enter into any discussion or correspondence about these
marking schemes.
GL1
Question 1
(a)
X = umbo (1)
Y = pallial sinus (1)
[2]
(b)
(4x1)
Bivalves
Symmetry within
one valve

Size of one valve

compared to the other
(c)
(d)
[4]
Brachiopods
Asymmetrical
or none

Same size

Different
sizes
Symmetrical
Presence of teeth and
sockets

Yes

Yes
Muscle scars

Adductor only

Diductor

Adductor
(i)
Mould (1)
[1]
(ii)
Calcium carbonate/calcite (1)
Solution/dissolves (1)
In acidic
(1)
Groundwater/solution/fluids etc. (1) (3 of these)
[3]
Preserved in life position/in situ (2)
or
Not transported (1)
before preservation (1)
[2]
Death assemblage because:
Fragmented/disarticulated/broken/damaged (1)
shows they have been moved before preservation (1)
[2]
(i)
(ii)
Total 14 marks
1
Question 2
(a)
(i)
(ii)
(iii)
(b)
G = Biotite mica (1)
H = Orthoclase feldspar (1)
[2]
Mineral H cooled at slower rate (than G)
or they cooled at different rates (R) (1)
and one other valid point, such as:
At varying depths in the crust/lithosphere (1)
Reference to order of crystallisation (1)
Reference to relative crystallisation temperatures (1)
[2]
Granite (1)
[1]
Answer should cover 4 of the following:
Quartz harder then Feldspar (1)
Therefore Quartz resists erosion better (1)
Quartz lacks cleavage, Feldspar has 2 cleavages (1)
More likely that Feldspar will be broken during transport (1)
Quartz is chemically inert, Feldspar prone to
chemical breakdown (1)
therefore Quartz more likely to survive
weathering processes (1)
(c)
(d)
Biotite has been lost/broken down (1)
[4]
(i)
chemical weathering/hydrolysis (1)
[1]
(ii)
Any named aquatic sedimentary environment (1)
Low energy/deep/still water (1)
Low in oxygen (1) (2 of these)
[2]
Crystalline (1)
Foliated/aligned (1)
0.5-4.0 mm (1)
[3]
(i)
(ii)
2 of the following: (2)
quartz
muscovite or mica
biotite or mica
chlorite
plagioclase or feldspar
orthoclase or feldspar
garnet
hornblende
[2]
Total 17 marks
2
Question 3
(a)
(i)
52 degrees (accept 50-55) (1)
[1]
(ii)
Concept of distance/time in calculation (1)
Correct calculation of km/m yr (based on latitude in a(i)) (1)
[2]
A = horizontal arrow (1)
B = arrow dipping down towards B, but less steeply
than the one for the present day (or lower number) (1)
[2]
(i)
Any named igneous rock (1)
[1]
(ii)
Iron minerals (1)
Align with magnetic field (1)
At time of their intrusion/eruption/cooling (1)
Curie temperature (1)
Irreversible/trapped/solidified (1)
(3 of these)
(iii)
(b)
(c)
(d)
Explicit reference to uniformitarianism or equivalent (R) (1)
And 2 of these
Reference to equator 300my (from fig 3) (1)
Corals are (most commonly) tropical (1)
Reference to limestone (1)
Discussion of modern non tropical corals (1)
Asthenosphere = plastic/weaker/partially molten/ flows (1)
Convection currents (1)
Continents (lithosphere) float/move on asthenosphere (1)
(2 of these)
3
[3]
[3]
[2]
Total 14 marks
Question 4
(a)
(b)
(i)
Fold axis bisecting either the antiform or the synform (1)
[1]
(ii)
Reverse fault (1)
Displacement 0.9-1.1m (1.8-2.2cm) (1)
Dyke cutting beds (i.e. discordant) (1)
Dyke displaced by fault (1)
[4]
(i)
Younger on top of older (or equivalent) (1)
[1]
(ii)
Rock of included fragment is older than rock in which
it is deposited (1)
[1]
(iii)
Sandstone lies above lava,
suggesting sandstone is younger (1)
No marks for “sandstone is younger than lava”
Conglomerate contains fragments of lava,
Suggesting conglomerate is younger than lava (1)
Sequence must be overturned, (1)
Sandstone is older than lava (1)
(c)
[3]
Name of appropriate sedimentary structure (1)
Precise location for the example (1)
Scale (1)
Quality of drawing/description (2)
Explanation of how/why it can be used as way up criterion (2)
(5 marks from these)
[5]
Total 15 marks
4
GL3
Question 1
(a)
(b)
Subduction zone (1)
Destructive/convergent plate boundary (1)
Energy/Stress release/friction (1)
(2 max)
[2]
(i)
2 hrs (2-1.75 hrs or 1hr 45mins) (1)
[1]
(ii)
Tsunamis explained (1 res)
(origin/wavelength/amplitude, speed
effect of shallowing 2 max)
Very large quake (1) Shallow focus (1)
Little energy reduction (1)
(Holistic max 3 marks)
[3]
(c)
Animals can “hear”/sense earthquakes/tsunamis that human can’t.
(P waves are longitudinal waves like sound).
They moved to higher ground/from the coast in time.
Monitoring animal behaviour may give warning (R)
Technique employed in China.
(Holistic - max 3 marks)
[3]
(d)
Less prepared
No infra structure
No warning system
Population density
Building type/density
(Holistic – max 3 marks)
[3]
Total 12 marks
5
Question 2
(a)
(b)
(c)
(d)
(i)
Dyke(1) Discordant (1)
[2]
(ii)
Dyke impermeable (1)
crystalline rock (1) Effect of pumping (1)
slows/prevents lateral flow (1)
(2 max)
Permeable (1) Specific retention (1)
Porous (1),
Jointed/fractured (1)
Textural characteristics
Loose packing (1)
Fragmental, (1)
Large (1) Angular clasts (1)
(2 max)
(i)
[2]
[2]
Surface below water table (1)
Pore water pressure (hydrostatic head) (1)
(1 max)
(ii)
Water table lower(1) – less pressure (1)
If water table falls slightly - need to pump.(1)
Effect of overpumping of A – cone of exhaustion (1)
(2 max) Accept saline water
(iii)
Saline water (1)
Exhaustion (1)
Subsidence (1)
(2 max)
[1]
[2]
Heat, hot water – unbearable for humans.
Gas – poisoning,
Earthquakes – collapse
(any hazard not associated with eruption e.g. lava)
(2 max)
[2]
Total 13 marks
6
Question 3
(a)
Describe the geological problems often associated with the extraction
of rock or minerals from the ground.
[10]
stability of working faces
ground subsidence
gas explosions
flooding
surface/groundwater pollution
waste tipping
Examples credited
(b)
Explain the relative importance of two of these problems
with reference to one or more mining operations you have studied
[15]
Two chosen. Detail of the problems in specific case studies.
Holistic (7+7+1)
Total 25 marks
7
Question 4
Using one or more case studies,
(a)
Describe the extent to which the destructive effects of lava flows might be controlled.
[10]
Discussed using examples. Ultimately little management/control if people choose to
live near volcanoes.
Case studies - Iceland, Etna etc. NO CASE STUDIES (MAX 7 )
Evacuation, hazard mapping, diversion/blocks, dropping-spraying with water,
explosion of flow margin, prediction devices.
Extent needed for max marks.
(10 marks)
(b)
Explain the difference in the hazards typically associated with the eruption of
(i)
basaltic (silica rich) and
(ii)
andesitic (silica poor) magmas
[15]
Different magmas have different characteristics that affect viscosity
Nature of hazard depends upon composition, viscosity and gas content.
(i)
Basaltic - mafic and Non viscous
- gas readily escapes – not explosive (red volcanoes)
- less ash – localised hazard
- Fluid lava main hazard – Fast moving (initially few Km/hr)
- Fire fountains
- flows further – more hazard to property on lower slopes.
- hotter initially (1000 degree)
- Flood basalt and climate change credited
Examples. (Nyirongongo, Iceland, Hawaii, Nyos, Columbia etc.)
(ii)
Andesitic – intermediate and Viscous magma
- gas does not easily escape – explosive (grey volcanoes)
- bombs
- Blast hazard
- Much ash/bombs – worldwide effect
- Pyroclastic flows
- Lava slow moving (10's m/hr to few m/day)
- associated with lahars.
- Tsunamis
- landsides
Examples (Pinatubo, Mt St Helens, Vesuvius, Krakatoa etc.)
Total 25 marks
8
Question 5
(a)
Describe the engineering activity that can speed up or slow down the effects of
longshore drift in coastal areas.
[10]
longshore drift described
Groynes, breakwaters, harbours, seawalls, rip-rap, slope drainage and
reprofiling, etc. Examples credited.
(b)
Explain the hazardous effects of such interference with the coastal system.
[15]
Cliff erosion is slowed by groynes/seawalls/rip-rap etc which
Protect base of cliff from undercutting preventing release of sediment
Provide stability, e.g. toe of landslide, etc – loss of potential sediment source.
Increases the size of the beach – reduces energy of waves in engineered area
This results in changes in longshore drift pattern as
Reduction in amount of sediment available
Reduction in deposition in unprotected parts of the coast
Results in increased marine erosion in unprotected area
Diagrams and Examples given credit.
Total 25 marks
9
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