12

Mas

ter1

Géo

logi

e de

s Ré

serv

oirs

Dyn

amique

des

Bas

sins

- M

iche

l Sér

anne

23 Different types of basins according to plate tectonic setting: spatial and temporal evolution from one type to another

Mas

ter1

Géo

logi

e de

s Ré

serv

oirs

Dyn

amique

des

Bas

sins

- M

iche

l Sér

anne

24

1.2. Sedimentation: External forcings

• Tidal sediments = Sediment deposition controled by the tides (cyclic phenomenon). • Tides results from combined attraction of the Moon and the Sun on the oceans (& on the crust). • Sedimentation records variations of parameters external to the Earth

Burdigalian (Digne foreland Basin)

Present: Baie du Mont Saint Michel

13

Mas

ter1

Géo

logi

e de

s Ré

serv

oirs

Dyn

amique

des

Bas

sins

- M

iche

l Sér

anne

25

• Periodic changes in the Earth’s orbital parameters affect the amount of radiation from the Sun. • The energy dissipated by the Sun varies with time => variation in radiation received by the Earth. ⇒ The total amount of solar radiation received on the Earth’s surface governs

long-term (100’s of millions of years) and short-term (10-1000’s years) temperature of the atmosphere and hydrosphere. Through complex feedback loops, this has direct and indirect consequences on Climate and associated exogenic transfer processes.

=> Climate forcing affects the way the sedimentary basins are filled

Energy

External forcings

Mas

ter1

Géo

logi

e de

s Ré

serv

oirs

Dyn

amique

des

Bas

sins

- M

iche

l Sér

anne

26

Sun’s energy Sun’s energy

1m2 ->342W/m2

1.41 m2 ->242W/m2 45°

90°

tilt

NO tilt • No seasonal variation of insolation • Increased yearly average temperature

• High latitudes receives less energy than inter-tropical areas • Insolation seasonal variation

Insolation : sun’s energy

Energy from the Sun

= 10 000 x energy

from internal Earth

14

Mas

ter1

Géo

logi

e de

s Ré

serv

oirs

Dyn

amique

des

Bas

sins

- M

iche

l Sér

anne

27

Milankovitch cycles

T= tilt or obliquity

E = eccentricity

P = precession

• Orbital parameters of the Earth have been acting over the whole history of the planet (albeit changes in periodicity and amplitude). • Milankovitch cycles have been recorded in sediments with different intensity through time. • During Quaternary, Milankovitch cycles are particularly well expressed (Glaciations stages)

Mas

ter1

Géo

logi

e de

s Ré

serv

oirs

Dyn

amique

des

Bas

sins

- M

iche

l Sér

anne

28

insolation => climate => sedimentation

©ArthusBertrans

Atmosphere Hydrosphere Biosphere

Temperature, pluviometry, seasonnallity, …

Erosion, weathering, life, river transport, ocean circulation…

Sun energy

©NASA sedimentation

15

Mas

ter1

Géo

logi

e de

s Ré

serv

oirs

Dyn

amique

des

Bas

sins

- M

iche

l Sér

anne

29 © Y. Hamon

© Y

. Ham

on

Hettangian (S-Cevennes) records cyclic flooding and desiccation of shallow carbonate platform. Sedimetary record counts tens of cycles subdivided into 5 smaller cycles; interpreted as eccentricity (100ky) combined with precession (20ky) forcing

Oligocene evaporites (Portels/Corbières)

record of seasonnal, cyclic desiccation of lagoon

© M. Séranne

Periodic changes in forcings => sedimentary cycles

Mas

ter1

Géo

logi

e de

s Ré

serv

oirs

Dyn

amique

des

Bas

sins

- M

iche

l Sér

anne

30

Periodic changes in forcings => cycles • Periodic (or not) changes in the controlling processes => record cycles

• Signals of different time/space scale => record of stacked (nested) cycles - several nested sequences in the stratigraphic record

• Combination of stacking of several signals => complex stratigraphic record -  Basin analysis aims at deciphering these signals -  sedimentary basinfill contains these signals => Archives

16

Mas

ter1

Géo

logi

e de

s Ré

serv

oirs

Dyn

amique

des

Bas

sins

- M

iche

l Sér

anne

31

© M

. Séranne

Tertiai

re

Crétac

é

Chicxulub impact

Non-periodic changes in forcings => catastrophic events

Mas

ter1

Géo

logi

e de

s Ré

serv

oirs

Dyn

amique

des

Bas

sins

- M

iche

l Sér

anne

32

Tonga, March 2009

Volcanism -> ashes in atmosphere -> modify climate Volcanism -> ashes -> widespread & contemporaneous deposits -> correlation & dating

Non-periodic changes in forcings => record of events

One cinerite bed (ashes layer) interbeded the continental cyclic lacustrine siltites of the Permian Lodève Basin.

17

Mas

ter1

Géo

logi

e de

s Ré

serv

oirs

Dyn

amique

des

Bas

sins

- M

iche

l Sér

anne

33

Sediment or not sediment ? Sediments are deposited and preserved in some parts of the basins, not everywhere, not at all time ⇒  incomplete and inhomogeneous record related to basin depositional evolution ⇒ Basin dynamics accounts for sediment distribution in space and time

Stratigraphy (≠ sedimentology) = study of sediment stacking pattern

Mas

ter1

Géo

logi

e de

s Ré

serv

oirs

Dyn

amique

des

Bas

sins

- M

iche

l Sér

anne

34

Sediment accumulation rate

Sediment thickness (m)

Observed

Deposits age (Ma) Modeled from several datings

Sedimentary deposits are an uncomplete and distorted record of time

Time hiatus = no deposit correlates with this time interval => Eroded or never deposited?

Sedi

men

t th

ickn

ess

(m)

Deposits age (Ma)

Slow accumul. rate

Fast accumul. rate

hiatus

•Sediment accummulation rate varies through time in basins. • Depends on sedimentary processes, paleogeography, sediment flux, subsidence…

18

Mas

ter1

Géo

logi

e de

s Ré

serv

oirs

Dyn

amique

des

Bas

sins

- M

iche

l Sér

anne

35

Exercise : Sediment accumulation rate

Carixian

Hettangian

Late Triassic

Sinemurian"Calcareous"

Lias

"Marly" Lias

Domerian

Aalenian

Toarcien

Bajocian

Bathonian

Callovian

Kimmeridgian

Dogger

Triassic

L. Oxfordian

Portlandian

EarlyCretaceous

(Neocomian)

LateCretaceous

Berriasian

Valanginian

Lutetian

Bartonian

Priabonian

Eocene

0

0.5

1.5

2.5

1

2

3

3.5

Synthetic lithostratigraphy and tectonic evolution of Languedoc

Maastrichtian

E. EocenePaleocene

L. Rupelian

Langhian

Pliocene

Stratigraphy

Early TriassicVariscan basement

Aquitanian

Burdigalian

Malm

E. Miocene

Pliocene

Oligocene

Lithographiccolumn

approx.thickness

km

mid-CretaceousErosion

Thru

stin

g &

grow

th s

trata

Gul

f of L

ion

Mar

gin

Rifti

ngTh

erm

al s

ubsid

ence

break-upunconformity

Messinianerosion

Pyre

nean

fore

land

bas

in

riftingunconformity

onset of Tethyan rifting

North

Tet

hyan

Mar

gin

"Bas

sin d

u Su

d-Es

t" (T

ethy

an a

borte

d rif

t)

Voco

ntia

n p

erio

d

Discontinuities

E.Pyrenean unconformity

EmmersionRe

newe

dsu

bsid

ence

Ther

mal

sub

siden

cerif

ting

gra

vitat

iona

l

list

ric fa

ultin

gin

vers

ion

Tectonics

Med

iterr.

desic

catio

n

FluviatileSabkha

Lagoonal platform

Carbonate ramp

Reef platform

Slope

Basin

LacustrineAlluvial fans

Alluvial fans

Alluvial fans

Fluviatile

Fluviatile

Shoreface

Gilbert-deltas

Fluviatile/lacustrine

Sedimentaryenvironments

bauxite

shal

lowi

ng-u

pde

epen

ing-

up

cont

inen

tal

cont

. co

nt.

mar

ine

mar

ine

Mar

ine

sandstone

conglomerate

lacustrinelimestonemarl & silts

dolomite

evaporites

marly limestone

limestone

bioclasticlimestonegrainstone

Sedi

men

t th

ickn

ess

(km

)

Deposits age (Ma)

250Ma

70Ma

200Ma

130Ma

30Ma

20Ma

16Ma

50Ma

Compare sediment record and time: construct the accummulation curve for the Languedoc area 5Ma

0Ma

60Ma

140Ma

150Ma

175Ma

145Ma

160Ma

190Ma

200 150

0

50 0

1

2

3

100

100Ma

Languedoc

Mas

ter1

Géo

logi

e de

s Ré

serv

oirs

Dyn

amique

des

Bas

sins

- M

iche

l Sér

anne

36

Sediment accumulate in basins if:

1- there is a gravity-driven flux of sediment (erosion/ transport/ deposition) => base level

2- there is space available to trap the sediment => accommodation space

Sediment are generated if: • Deformation of the topographic surface of the lithosphere induced by internal forcing (mountain-building, volcanism, thermal uplift…). ⇒  Erosion of the topography, mobilization of detritals, transport, deposition. ⇒  All processes governed by gravity. ⇒  Processes strongly dependent on external forcing (climate…).

• Biological activity contributes to sediment flux. ⇒  in-situ carbonate production in favourable environments (« carbonate factory » in ocean, lakes) -> climate-dependent ⇒  reworked carbonates behaving as detritals ⇒  plants residues (coal)

• (Bio-) Chemical activity = weathering, alteration, evaporation, precipitation.

19

Mas

ter1

Géo

logi

e de

s Ré

serv

oirs

Dyn

amique

des

Bas

sins

- M

iche

l Sér

anne

37

Base-level

1

Base level (Wheeler, 1964) : •  is an abstract, non physical dynamic surface ; can be assimilated to an upstream-downstream profile in 2D sections •  is above the earth surface where deposition occurs, below where erosion occurs, and equal to the earth srface where there is an equilibrium (e.g., bypass) ; •  represents the surface where sediment flux would be constant (i.e., a balance would exist between sediment supply and removal) ; •  is a potentiometric surface (i.e., the surface along which the energy of sediment flux is minimized) ; •  is a dynamic surface (i.e., it vibrates with respect to the physical surface in time and space) ; •  exists in a system where space, energy and mass are conserved.

upstream downstream

Mas

ter1

Géo

logi

e de

s Ré

serv

oirs

Dyn

amique

des

Bas

sins

- M

iche

l Sér

anne

38

Available space => Accommodation Eustacy

Intraplate deformation Basin

subsidence

accommodation

2

Accommodation : it is the rate (measured in m/Ma) at which space is being made available for sediments to be trapped in the basin. It is the result of the vertical movements of the basement (subsidence + lithoshere deformation) and of eustacy (World ocean level). Sediment flux may or may not fill the availlable space. This is determined by the balance of sediment rate and accommodation. Sed. Rate < Accomm => underfilled basin, water depth increases (starved basin,

condensation surface) Sed Rate = Accomm => basin remains at the same water-depth => persistance of

sedimentary facies through time Sed. Rate > Accomm => basin being filled, water-depth decreases, coarsening and

shallowing up sequences.

20

Mas

ter1

Géo

logi

e de

s Ré

serv

oirs

Dyn

amique

des

Bas

sins

- M

iche

l Sér

anne

39

« Eustacy » vs « Relative sea-level change » Eustacy = variation of the global World Ocean (all seas & oceans being connected) this is due to changes in the shapes of the ocean floor ( variable rates of sea-floor spreading, mantle-convection induced uplift,…) or of the volume of water in the World Ocean (growth or decay of polar ice-caps, soil moisture, water thermal expansion…).

Haq Eustatic Curve

Relative sea-level change = variation of water depth in one basin. It’s the combination of eustacy, and local constraints: subsidence/uplift and sediment flux.

Several Eustatic Curves have been compiled and progressively improved (Haq, Miller, Kominz,…) . They can be applied everywhere.

Relative sea-level

Eustacy

Bst vertical mvt

sediment flux Relative sea-level change in a basin can be approached by analysis of the stratal architecture combined with sedimentary facies.

Mas

ter1

Géo

logi

e de

s Ré

serv

oirs

Dyn

amique

des

Bas

sins

- M

iche

l Sér

anne

40

Stratal geometry (for beginners…)

Canterbury Basin, New Zealand aggradation

progradation

Condensed section

Aggradation: Sed. Rate ≤ Accomm

Progradation : Sed Rate ≥ Accomm

2 mains patterns: several possible causes f(subsidence, sediment flux, sea-level)

bathymetry Divergent: Differential subsidence

Down-lap

Onlap

Sed. Rate > Accomm Sed. Rate < Accomm

Margin

VS Basin

21

Mas

ter1

Géo

logi

e de

s Ré

serv

oirs

Dyn

amique

des

Bas

sins

- M

iche

l Sér

anne

41

Fluvial & delta Slope shales

Reworked clastics

sequence boundary

Maximum Flooding Surface

Modifié d’après Bartek et al, 1991

0 +50 +100 -50 0

20

30

10

Oligocene

Miocene

Pliocene

Eustacy Sedimentation pattern of Neogene passive margins

Mas

ter1

Géo

logi

e de

s Ré

serv

oirs

Dyn

amique

des

Bas

sins

- M

iche

l Sér

anne

42 Valanginian, S. France

Orbital parameters of the Earth

variable sun energy

received

outer envelopes

temperatures sedimentation climate Stratigraphic

record

22

Mas

ter1

Géo

logi

e de

s Ré

serv

oirs

Dyn

amique

des

Bas

sins

- M

iche

l Sér

anne

43

Sedimentology : lithofacies

Lithofacies is the set of physical features of a sedimentary rock. Lithofacies provides info on depositional conditions.

Lithofacies = Lithology Texture structure Geometry of the

sedimentary body

Mode of association of constitutive elements

Mineralogy, granulo, morphometry

Hydrodynamics biochemicals, biological indicators

Mode of transport & deposition

Source, transport, duration, environment,bathymetry

Mas

ter1

Géo

logi

e de

s Ré

serv

oirs

Dyn

amique

des

Bas

sins

- M

iche

l Sér

anne

44

synthesis

Sedimentary basins result from the complex interaction of internal and external forcings_ “Reading” the sedimentary record allows to decipher the controlling factors and their temporal evolution.

24

Mas

ter1

Géo

logi

e de

s Ré

serv

oirs

Dyn

amique

des

Bas

sins

- M

iche

l Sér

anne

47 Fossil energy

Argiles imperméables

1.3.Sedimentary basins & societal issues

Geothermy

Iron ore

sequestration

Natural resources

Stones

Salt

Gas storage

Aquifers

Mas

ter1

Géo

logi

e de

s Ré

serv

oirs

Dyn

amique

des

Bas

sins

- M

iche

l Sér

anne

48

erosion & weathering

eosion & weathering

Dissolved metallic ions

Sediments Sediment deposition & ions precipitation

© P

.J.C

ombe

s

Natural Reactor = ore formation

ores subsidence

25

Mas

ter1

Géo

logi

e de

s Ré

serv

oirs

Dyn

amique

des

Bas

sins

- M

iche

l Sér

anne

49

Organic mater

(anoxiclake)

Biosphere (Carbon)

Biosphere

soil sol

Maturation f(temperature, pressure, time): Organic matter -> kerogene -> Oil -> gas!

burial

oil

migration

© M

. Sé

rann

e

Natural Reactor = hydrocarbons generation

Mas

ter1

Géo

logi

e de

s Ré

serv

oirs

Dyn

amique

des

Bas

sins

- M

iche

l Sér

anne

50

Consommation ressources naturelles /an / personne

Ressources minérales

eau Énergie fossile

La vaste majorité des ressources naturelles provient des bassins sédimentaires

26

Mas

ter1

Géo

logi

e de

s Ré

serv

oirs

Dyn

amique

des

Bas

sins

- M

iche

l Sér

anne

51

(estimations en 2000)

Mas

ter1

Géo

logi

e de

s Ré

serv

oirs

Dyn

amique

des

Bas

sins

- M

iche

l Sér

anne

52

Mauriaud & al, 2013 « La faim du pétrole »

Réserves & ressources mondiales de Pétrole et de Gaz

Réserves mondiales de Charbon

Ressource > 15000 Gtec ; Production = 5Gtec/an Gtec: 109 tonnes équivalent charbon

Pétrole : 2000 Gbep (dont 80% conventionnel) Gaz : 2500 Gbep (dont 49% conventionnel) Gbep: 109 barils équivalent pétrole en 2010 Réserves mondiales de pétrole & gaz= 2665 Bboe Bboe: Billion Barrel Oil Equivalent = 109 barils équivalent pétrole

conventionnel

Pétrole Gaz

non-conventionnel