WJEC A2 Geology

BGS Mapwork Exercises

I.G.Kenyon

Quartz Dolerite

The Geology of Hadrian’s Wall

Describe the strike and dip of the rocks shown on the map extract

Outline, using map evidence the likely form of the quartz dolerite intrusion

N

The Geology of Wenlock Edge, Shropshire

N10

9

Describe the strike and dip of the beds shown on the extract above

Silurian Rocks

X

Y

Geology and Topography of Wenlock Edge, Shropshire

Cross section along line X-Y from the map on the previous slide

X Y

Boulder Clay

Using the geology map on the previous slide and the cross section above, outline the

relationship between lithology and topography

Wenlock Limestone

Periglacial Head

LowerLudlow Shales

Aymestry Limestone Upper Ludlow Shales

Clitheroe 1:50,000 Sheet 68 Solid & Drift

Describe the strike and dip of the beds in this box

Suggest reasons to explain the V-shaped outcrop pattern here

Ayr 1:50,000 Sheet 14(W) Solid

Describe and identify the fold structure within this box

Describe the likely form of the igneous

intrusion here

This fault dips South West, identify the type of fault

Exeter 1 inch : 1 mile Sheet 325 Solid & Drift

Basic igneous rocks

NCarboniferous grits and shales

Permo-Triassic breccias and

conglomerates

Using this slide and the next, try to identify the types of igneous features

Exeter 1 inch : 1 mile Sheet 325 Solid & Drift

Section along southern margin of the map of previous slide

Dolerite (D)

Carboniferous grits and shales

Perm-Triassic breccias and conglomerates

Tuffs

Basalt(B)

Identify the types of igneous features

Hexham 1 inch :1 mile Sheet 19 Solid

Identify the main fold structure in the yellow box, refer to dip and strike values, symmetry and plunge where appropriate

Okehampton 1 inch : 1mile Sheet 324 Solid & Drift

Line of cross section on next slide

Describe the outcrop pattern of igneous rock D and identify the type of intrusion

Estimate the width of the metamorphic aureole around the granite above

Granite

Okehampton 1 inch : 1mile Sheet 324 Solid & Drift

Describe the fold structure between A and B on the cross section below

A B

What map evidence is there to confirm that this part of the bed is overturned? How could you confirm this in the field?

LLandrindod Wells 1:25,000 Sheet 15/16 Solid

Describe the map evidence to suggest there is a plunging syncline and anticline on the extract above. In which direction are the folds plunging?

LLandrindod Wells 1:25,000 Sheet 15/16 Solid

This fault plane dips East at 76° Identify

the fault type

N

Harlech 1:50,000 Sheet 135 Solid

C D

Describe and identify the major fold structure along line C – D. Refer to strike and dip, symmetry and plunge where appropriate

This fault dips SSE at 70° Identify the type of fault

Wrexham 1:50,000 Sheet 121 Solid

Silurian

Carboniferous

Compare and contrast the strike and dip values of the Silurian (b)

and Carboniferous (d) Beds

This bed is a basal conglomerate, explain the significance of this with respect to the junction between the

Silurian and Carboniferous beds

What happens to the conglomerate here?

Brough-under-Stainmore 1:50,000 Sheet 31 Solid

E

F

Using map evidence, describe and explain the outcrop of the Carboniferous beds in the NE

corner of the extract

The Hilton Fault dips SW at 80° Identify the fault type

Brough-under-Stainmore 1:50,000 Sheet 31 Solid

Describe and identify the major geological structures shown on the cross section above

b = Ordovician d = Carboniferous e = Permian

f = Triassic

d

E

F

Lake District 1:250,000 Sheet 54°N - 04° West SolidPermian

Carboniferous

Ordovician

SilurianIdentify 2 unconformities on the map extract

Describe the likely nature of these

igneous intrusions

Lake District 1:250,000 Sheet 54°N - 04° West Solid

Shap Granite

CarboniferousPermianSilurian

Ordovician Ordovician

Identify 2 unconformities on the cross section above, use information from the previous slide to help you

Monmouth 1:50,000 Sheet 233 Solid & Drift

G H

Describe and identify the major fold structure along line G – H on the map extract

A

B

CIdentify the structures shown

in boxes A, B, C and D

D

Note-basal conglomerate

The Roaches & Upper Dove Valley 1:25,000 Sheet SK06 Solid & Drift

Identify the major fold structure in the box above, refer to strike, dip, symmetry and plunge where appropriate

The Roaches & Upper Dove Valley 1:25,000 Sheet SK06 Solid & Drift

Landslide

Describe and identify the major fold structure on the extract above, refer to strike, dip, symmetry and plunge where appropriate. Outline

the likely reason for the occurrence of the large landslide on the map

Oldest bed

Church Stretton 1:50,000 Sheet 166 Solid

Dolerite

Describe the major fold structure in the

highlighted box, refer to strike, dip, symmetry and plunge where appropriate

Suggest, with reasons the likely form of the dolerite intrusion on the extract

Miller’s Dale 1:25,000 Sheet 17 Solid & Drift

Describe and identify the major fold structure on the extract above, refer to strike, dip, symmetry and plunge where appropriate

Bristol 1 inch:1mile Solid & Drift

Identify the major fold structure in the box on the map extract above

Describe the relationship between beds f6 and d2 on the map extract

Bristol 1 inch:1mile Solid & Drift

Describe and identify the major fold structure in this

area of the map extract

Bristol 1 inch:1mile Solid & Drift

Describe the relationship between the f6 Triassic beds and the Carboniferous

d1 to d3 beds on the extract

Describe and explain the nature of the

faulting in this area

Identify the major fold structure in this area

Pembroke & Linney Head 1:50,000 Sheets 244/245 Solid & Drift

Q

P

Describe and identify the major fold structures along line P – Q

Check your answer on the next slide

Pembroke & Linney Head 1:50,000 Sheets 244/245 Solid & Drift

Describe the major fold structures on the cross section above. Suggest areas where beds are likely to be overturned. What field evidence could you look for to prove some limbs were inverted?

Pembroke & Linney Head 1:50,000 Sheets 244/245 Solid & Drift

Identify and describe 2 major fold structures on the map extract, refer to strike, dip, symmetry and plunge where appropriate

Maidstone 1 inch:1 mile Sheet 288 Solid & Drift

Line of section on next slide

K

J

This fault plane dips S at 77° State the type of fault

N

Check your answer on the next slide

Maidstone 1 inch:1 mile Sheet 288 Solid & Drift

KJ

NorthSouth Reverse Fault

Hanging wall upthrown Footwall

downthrown

How could you calculate the throw of the fault?

Lands End 1:250,000 Sheet 50N 06W Solid

St.Austell Granite

Edge of metamorphic aureole

Describe and account for the shape of the metamorphic aureole around the St. Austell granite

Maidstone 1 inch : 1 mile Sheet 288 Solid & Drift

Describe the drainage pattern shown in the North and Eastern part of the map

Swansea 1:50,000 Solid Sheet 247

Identify the main fold structure, refer to dip and strike, symmetry

and plunge where appropriate

N

This fault plane dips WNW at 67°, state the type of fault

Swansea 1:50,000 Solid Sheet 247The Grovesend Fault

dips East at 40°

This fault dips west at 47°

Identify the structure between these 2 faults

Identify this fault structure

X

Y

Swansea 1:50,000 Solid Sheet 247

Cross section along line X-Y on previous slide

Describe the major fault structures on the cross section below

Coventry 1:50,000 Solid & Drift Sheet 169A

B

Describe the strike and dip of the coal seams in boxes A and B

Account for the variation in outcrop pattern of the coal seams

in boxes A and B on the map extract

Coventry 1:50,000, Solid & Drift Sheet 169

Describe the map evidence to support the idea there is an angular unconformity within highlighted box A on the extract above

A

Newton Abbot 1:50,000, Solid & Drift Sheet 339

Describe and account for the drainage pattern developed on the granite on the western side of the map extract

Granite

Newton Abbot 1:50,000, Solid & Drift Sheet 339

Granite

Dolerite

m = metamorphic aureole

Give 2 pieces of map evidence to show that the granite intrusion is younger than the dolerite on the extract above

What type of intrusion is represented by

the dolerite?

Newton Abbot 1:50,000, Solid & Drift Sheet 339

Dolerite

Black Shales

A major quarry is located in box A above. Outline 2 problems that the local geology may present to the quarrying activity.

A

75

Newton Abbot 1:50,000, Solid & Drift Sheet 339

Impermeable Breccia

Permeable Sandstone

Periglacial Head Gravel-Permeable

Landslip

Outline the factors that may explain the formation of the landslip shown on the extract above

State the map evidence for these

beds being horizontal

The End