04_Strat__2010_10_22l-3

Dynamische Bild der Erde (LA) Hugh Rice

Rocks types

Magmatic rocks(das magmatische Gestein, der Magmatit)

(intrusiv, extrusiv)

Sedimentary rocks(das Sedimentgestein)

Metamorphic rocks(das metamorphe G., das Metamorphit)


Rock cycle

WeatheringErosion

Deposition

Sedimentaryrocks

Metamorphic rocks

MeltingMantledifferentiation

Igneousrocks

Exhumation

Lithification

Magma formation

Metamorphism

Meta-morphism

Not to any scaleat all!

sea level


Rocks

Need methods to:

1) determine the relative and absolute ages of rocks.

2) divide rocks into parts that canbe easily described.


Sedimentary layering


Sedimentary layering

Photo Erich Draganits


Bedding


Steno Principles

1 - Principle of Superposition.(Das Superpositionsprinzip.)

2 - Principle of Horizontality.(Das Horizontalitätsprinzip.)

3 - Principle of Lateral Continuity. (Das Lateralkontinuitätsprinzip.)


N

3 - Lateralcontinuity

Finland

rwy

No

a

Sw

een

dG

lf of

Bot

hnia

uOccurrences ofAlum Shale in

Sweden(50-200 m thick)

0 500

km


1 - Superposition

Photo John Ramsay


2 - Horizontality


Unconformity(die Discordanz)

An unconformityis present when there is a

between a layer of sedimentary rock

and the underlying rocks.

time gap


Unconformity types

non-conformity

paraconformity

disconformity

angular unconformity

(no German equivalent).

(die maskierte Discordanz).

(die ungleich Discordanz).

(die Winkeldiscordanz).


640 Ma

800 Ma

Disconformity

640 Ma

800 Ma


Unconformity - 1

200 Ma

320 Ma

200 Ma

320 Ma


Unconformity - 2

Indian molasse - both < 30 Ma oldphoto Bernhard Grasemann


Sea-level changes

TRANSGRESSIONSea-level

RISEoastliC

ne

REGRESSIONSea-level

FALLoastliC

ne

Land

Sea

Land

Sea


20,000yearsago


Sea-level - Late Cretaceous94 Ma


sea-level changesRELATIVE

Affect the area of the continents.

Eustatic - world wide.

Isostatic - local.


Isostatic sea-level change

Isobases (m)for 6,000 BP

500 km

100

75

50

25 0

100

Shows uplift from sea-level since 6,000 BP.

Note that the points then atsea level were not the land

surface, since the ice depressed the land to

below sea-level).

.Uplift continues at up to-19 mm yr


Stratigraphy

Lithostratigraphy - the actual rocks.

Chronostratigraphy - the age.

Biostratigraphy - the fossil content.


SupergroupGroup Subgroup

Member

Bed (sediments) / Flow (volcanic)

FORMATION

Lithostratigraphic division


VE

ST

ER

TA

NA

BR

EIV

IKS

TA

PP

OG

IED

DE

Mann-drapselva

Innerelva

Lillevatnet

MORTENSNES

NY

BO

RG

SMALFJORD

GRP. FM. Mbr.

(do NOT learn)

5km

N

30

0 m

Lithostratigraphy


Distance (10s to 100s of km)

Tim

e (

Ma

)Formation B

Formation A

Diachroneity


Time divisions(chronostratigraphy)

EON (die Äon) - Archean, Proterozoic, Phanerozoic;

ERA (die Ära) - Palaeozoic, Mesozoic, Cenozoic occur in the Phanerozoic;

PERIOD (die Periode) - E. Palaeozoic - Cambrian, Ordovician, Silurian; L. Palaeozoic - Devonian, Carboniferous, Permian; Mesozoic - Triassic, Jurassic, Cretaceous; Cenozoic - Palaeogene, Neogene, Quaternary.


Biostratigraphy - fossil data

Good biostratigraphic fossils are:

- easily found, everywhere;

- constrains time well;

- sharp boundaries.

Common

Short time range

Fast evolution/extinction


Invertebrates - macrofossils(e.g. ammonites)


Jurassicbiostrat.

74 ammonitezones in55 Ma

= ca. 0.75 Maper zone.

(do not learn)


Microfossils - better

Apectodinium augustum, a dinoflagellate at the Palaeocene-Eocene boundary in the N. Atlantic. Photo Omar Mohamed, Graz Uni.

planktonic (widely dispersed),abundant, rapid evolution

PPL 20µ REM 20µ


Terrestrial biostratigraphy

Nypa, shrub salt-water palm, from SE Asia, Eocene.Photo Christa Hofmann, Uni. Wien

20µ 5µ

Fossil plants (pollen) are OKMicromammal teeth are better


Trace fossils (Ichnofossils)


Fossil diachroneity - 1

Evolution and spreading rate

Environmental constraints


Fossil diachroneity - 2

TimePlane

t tLithos ra .

Bo n au d ryBi t .os rat

Boundary

TimePlane

Volcanicevent


Eocene (54 Ma) ash-fall (mm)

Goban Spur

Fur

Iceland

Anthering

Untersberg


(do NOT learn this figure- it is way out of date)Unified stratigraphy

STEPHANIAN

WESTPHALIAND

WESTPHALIANC

WESTPHALIANB

WESTPHALIANA

NAMURIAN

UPPERCOAL

MEASURES

MIDDLECOAL

MEASURES

LOWERCOAL

MEASURES

RADSTOCKIAN

STAFFORDIAN

YORKIAN

LANARKIAN

I

H

G

F

E

D

C

B

A

Anthracoceras

Gastrioceras

Prolifera

Tenuis

Phillipsi

Up. Similis-pulchra

Low. Similis-pulchra

Modiolaris

Communis

Lenisulcata

Chrono-strat.

Litho-strat.

PlantDivisions

FloralZones

GoniatiteStages

Non-marineBivalvezones

Biostratigraphy

04_Strat__2010_10_22l-3

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