Upper Palaeozoic in the British isles

Question 1

What orogeny occurred in the Devonian to the Carboniferous?

Answer 1

Variscan (rheic ocean closing)

Question 2

What had an influence on the shape and geometry of the variscan orogeny?

Answer 2

The Caledonian orogeny

Question 3

What is the chronology of the Devonian?

Answer 3

416-359 Ma

Question 4

What rock formation was established in the devonian?

Answer 4

Old Red Sandstone (ORS)

Question 5

What was the paleoenvironment of Britain in the Devonian?

Answer 5

Largely non-marine
Marine in South/ South West

Question 6

What was the continental configuration of the Devonian?

Answer 6

Great southern continent (Gondwana)
With large continental area of South pole

Question 7

What are some non-marine basins of the UK Devonian outcrop?

Answer 7

Anglo-Welsh Basin
Caledonian Basin
Orcadian Basin

Question 7

What present day continents made up Gondwana?

Answer 7

South America
East Antarctica
NW, NE and S Africa
India
Arabia

Question 8

How can the thickness of the Devonian successions in the UK be described?

Answer 8

Extremely thick (South wales basin ~7000m)

Question 9

What are the characteristics of the Devonian basins in the UK?

Answer 9

Fluvial and alluvial sediments
Sandstones, conglomerates and mudstones
Abundant calcretes
Some lavas
Middle Old Red Sandstone

Question 10

What are calcretes?

Answer 10

Soils with carbonate concretions- evaporating conditions

Question 11

What is the oldest part of the black mountains in Pembrokeshire?

Answer 11

Brownstones (mainly sandstones and conglomerates)

Question 12

What is the Devonian deposition at freshwater west Pembrokeshire like?

Answer 12

Red sandstones, Conglomerates, Calcretes
Beaconite trace fossils

Question 13

Where is the Orcadian basin in the UK?

Answer 13

NE Scotland

Question 14

What does Orcadian basin show evidence of?

Answer 14

Cyclicity

Question 15

What is the upper devonian stratigraphy like in the Orcadian basin?

Answer 15

breccias, volcanics at base, fluvial sandstones,
conglomerates & calcretes above

Question 16

What is the Middle devonian stratigraphy like in the Orcadian basin?

Answer 16

fluvial & then lake sediments
* sun-cracked mudstones
* sandstone
* impure limestone, with freshwater fish

Question 17

What evidence can be gathered for the Orcadian basin?

Answer 17

Well preserved fish
Arid varves indicating seasonal variability

Question 18

What is the marine devonian basin in SW England called?

Answer 18

Culm basin

Question 19

What extinction events occurred in the Devonian?

Answer 19

Kellwasser (Frasnian)
Hangenberg (Famennian)

Question 20

What was the cause of the Kellwasser and Hagenberg extinctions?

Answer 20

widespread anoxia

Question 21

What lifestyle was most affected by the kellwasser extinction?

Answer 21

Benthic (seafloor organism)

Question 22

What are some examples of fauna affected by kellwasser?

Answer 22

Reefs (stromatoporoids, tabulate and
rugose corals);
Trilobites,
Brachiopods,
Ammonoids
Graptoloids go extinct

Question 23

Where environments did extinction occur for the Hangenberg event?

Answer 23

Marine and freshwater

Question 24

What distinct change occurred to fish populations in the Hangenberg event?

Answer 24

Placodermi extinction allowing space for present day fish species

Question 25

What rock type was implaced during the Variscan orogeny?

Answer 25

Granites

Question 26

What series is the Carboniferous split into?

Answer 26

Mississippian Pennsylvanian

Question 27

What onshore outcrops of the Carboniferous are there in the UK?

Answer 27

Midland Valley Scotland NE and Pennines S Wales and Devon

Question 28

What was the global position of the UK in the Mississippian?

Answer 28

Britain is found near the equator

Question 29

What are Goniatites?

Answer 29

A type of molluscs which is a key indicator of marine conditions as it acts as a biostratigraphical marker

Question 30

What are some examples of shallow marine macrofossils from the Mississippian?

Answer 30

Crinoids Brachiopods Lithostrontian (colonial coral) EKvasophyllum (solitary coral)

Question 31

How can the pre-Carboniferous topography be described?

Answer 31

Block and Basin

Question 32

How does the block structure affect thickness of sediment?

Answer 32

High relief = erosional Low relief = depositional

Question 33

What affect does underlying granite have on rocks?

Answer 33

Granite it buoyant so will "push" up overlying rocks

Question 34

What does block and basin topography control the nature of?

Answer 34

Sedimentation

Question 35

What are the characteristics of the Mississippian limestone facies?

Answer 35

Shallow marine reefs and crinoidal banks, shelly coral biostromes Platform carbonates on flanks of landmasses

Question 36

What is the name of the end Mississippian (Namurian) facies?

Answer 36

Millstone grit facies

Question 37

How was the millstone grit produced?

Answer 37

Pulsed marine transgression making sediment more uniform Coarse siliclastic sediments

Question 38

What occurred in the late Carboniferous?

Answer 38

Culmination of the Variscan orogeny Creation of Pangea (UK equatorial)

Question 39

What are potential analogues for the depositional environments of the late carboniferous?

Answer 39

Large modern deltas (Ganges, Mississippi and Okavango)

Question 40

What will happen within the sequence of a delta is there is a recession?

Answer 40

Channels will cut into the rock sequence

Question 41

What is the transition of rock type from marine to deltaic/ shelf in the late Carboniferous?

Answer 41

Carbonate (marine) to Clastic

Question 42

What is the Yoredale?

Answer 42

Sedimentary cycle of the mid to late Carboniferous

Question 43

What are the characteristics of the Yoredale?

Answer 43

Generally north of the Craven Fault Essentially marine. Coals rare. High frequency, low amplitude

Question 44

What are the characteristics of the millstone grit?

Answer 44

lower parts - deep-water turbidites, upper parts - shallow-water, sheet-like delta deposits, thin coals. Marine influence progressively rare

Question 45

What are the characteristics of the coal measures?

Answer 45

Fluvio-lacustrine, humid, water-logged depositional setting. Marine influence all but absent. Driven by autocyclic processes (e.g. lobe or channel switching) and local tectonics

Question 46

What environment developed in the Pennsylvanian in Europe and North America and what is the problem and benefit for the UK?

Answer 46

Coal swamps Benefit provided power for development Negative is enhanced green house effect

Question 47

Where was Britain located globally in the Permian?

Answer 47

Britain to N of Central Pangean Mountains - influence rainfall and sediment supply

Question 48

Where are the main deposits of the Permian in the UK?

Answer 48

SW midlands and NE England

Question 49

What type of deposit is linked to the Permian?

Answer 49

New Red Sandstone

Question 50

How many stages are there in the Permian and do they link to the UK?

Answer 50

9 but largely redundant in the UK

Question 51

What occurred from the transition from the Carboniferous to the Permian?

Answer 51

From ice house to greenhouse

Question 52

How can the Permian be identified in the East UK?

Answer 52

Earlier Rotliegend (red & yellow sediments), succeeded by Zechstein (evaporites and carbonates)

Question 53

How can the base of the Permian be identified?

Answer 53

Base often identified using (rare) plant assemblages or by dating volcanics

Question 54

How is the top of the Permian generally identified?

Answer 54

Taken below the first pebble bed in the Triassic Sherwood SST

Question 55

What processes would have dominated the end of the early Permian?

Answer 55

Aeolian deposits - creating Sabkhas (like those of modern day Qatar)

Question 56

What in the Permian acts as an important reservoir for oil and gas?

Answer 56

Early Permian SST

Question 57

What names are given to the Early to Mid Permian sequence?

Answer 57

Cisuralian (early Permian) to early Guadalupian (mid Permian)

Question 58

What are the names given from the Mid to Late Permian sequence?

Answer 58

Late Guadalupian to Wuchaipingian (late Permian)

Question 59

What marine transgression occurred in the late Permian?

Answer 59

Zechstein

Question 60

Why are so many faults appear to be present in the Carboniferous?

Answer 60

Due to the economic importance of coals, oils and gases in these rocks

Question 61

What economic deposit can be found in the late Permian?

Answer 61

Salt deposits

Question 62

What are the 2 stages of the zechstein?

Answer 62

First - carbonate rich shale throughout North Sea. Succeeded by carbonate units in NE England - the Magnesian Limestone

Question 63

How do the Zechstein deposits occur in east England?

Answer 63

series of cycles, 4 main lower, 1 minor upper cycle

Question 64

What are the zechstein cycles dominated by?

Answer 64

evaporites or carbonates or a mix of detrital and evaporates

Question 65

What are the zechstein cycles underlain by?

Answer 65

Marl slate

Question 66

What might have been the 2 reasons for the termination of a zechstein cycle?

Answer 66

Flood (Highstand) or Drying out (Evaporites/hypersaline phase)