3. depositional environments · • similar to fluvial channel • subaqueous levees mouth bars:...

3. Depositional environments Graduate programm – Introduction to Sedimentology

2013-11-15 Classification: Internal

2 - Classifi

cation:

Internal

2011-

04-01

Sedimentology: Weathering Erosjon Deposition

Mountain/rocks are

broken down

Weathering

Sediments are

dumped in a low lying

area (ocean/sea)

Deposition

Sediments are

transported by air,

water and ice

Erosion

Layer after layer is

deposited

due to the weight,

the ocean floor sinks

and more space is

made

Stratigraphy

Due to the pressure,

the sediments

become

compressed and

hard

A rock is born

Small pieces of rock

collectively called:

Sediments Low lying area in ocean &

sea where sediments end

up is called a

Basin

http://upload.wikimedia.org/wikipedia/commons/d/d4/Millet-Seed_Sandstone_Macro.JPG

3 - Classifi

cation:

Internal

2011-

04-01

Petroleum geology: Essentials

ProducabilityPermeability2) ProducabilityPermeability2)

StoragePorosity1) StoragePorosity1)

TIMING

Petr

ole

um

syste

m

Mature Source

Rock

Reservoir Rock Cap Rock and

Trap

Migration 150°C

65°C

Oil

Window

~100 Myr

4 - Classifi

cation:

Internal

2011-

04-01

Tectonic: Types of Faults

Normal Fault

Strike-slip Fault

Thrust/Reverse fault

Depositional environments

5 - Classifi

cation:

Internal

2011-

04-01

6 - Classifi

cation:

Internal

2011-

04-01


2013-11-15 9 Classification: Internal

• Continental

• Glacial

• Fluvial

• Deserts

• Shallow and marginal marine

• Deltaic

• Linear shorelines (Barrier, non-Barrier)

• Estuaries

• Deep marine

• Offshore (continental slope)

• Deep marine (basin floor)

glacial

aeolian lakes

Examples:

Peon, Norway

•Sequence stratigraphy


http://www.sepmstrata.org/movies/CLASTICSYSTEMTRACTS.MOV

Fluvial depositional environment – facies associations


• Channel fill

• Floodplain

• Levee

• Crevasse splay

channel

floodplain

levee

Flooded

floodplain

levee

channel

Crevasse splay


Fluvial planforms Meandering, braided and anastomosing river planform

Note!

Channel belt versus individual streams and bars

Meandering Braided

Anastomosing


Channel fill of meandering rivers

Lateral accretion

Donselaar


Emery and Myers 1995

Channel fill of anastomosing rivers

• Isolated channel fills

• Aggarading vertically

• Gravel to silt

• Planar tabular cross beds

• Downstream dune migration

• Small LA sequences

Makaske, 2001 Makaske, 2001

Makaske, 2001

Crevasse splay


• Breach of natural levee

• Rapid deposition on floodplain

• Sheet-like sandstone/siltstone bodies

• Mudstone interbeds

Levee

Floodplain

River

channel

Breaker point

Crevasse channel

Crevasse splay

Huesca, Spain, A. Kulikova, 2013

River avulsion


• Regional – new channel is established

• Local – meander cut-off – ox-bow lake

Regional avulsion Local avulsion

Taquari DFS, Pantanal Basin, Brazil

(image FSRG, Buehler et al., 2011)

Note!

Channel belt versus individual streams and bars

Sandstone body types


Channel fill:

• Ribbon-like

• Isolated lenses bars

• Sheet-like

Floodplain:

• Ribbon-like

• Thin sheet-like

Amalgamated sandstone bodies

• Combinatin of above

• Point bars develop

perpendicular to river flow

direction

• Lateral restricted sandstone

• Poor vertical connectivity

• Longitudinal bars develop parallel

to river flow direction

• Multistory/ multilateral sheet

sandstones

• Good vertical and lateral

connectivity

Hirst, 1991


Sinuous, meandering stream

Model 4Model 4

• Point bars - perpendicular to

flow direction

• Lateral restricted sandstone

• Poor vertical connectivity

Highly mobile braided stream

• Longitudinal bars - parallel to flow

direction

• Multistory/multilateral sheet-like

sandstones

• Good vertical and lateral

connectivity

Sandstone body types



glacial

aeolian lakes • Continental

• Glacial

• Fluvial

• Deserts


• Deltaic


• Estuaries

• Deep marine



Examples:

Lomvi, Norway, Rotligent,, UK


Desert depositional environment

• Aeolian blown sands

• Ephemeral lakes/rivers

• Alluvial fans

Nichols, 1999


Alluvial fans: types

• Gravity flow

• Sheetflood

• Channelised

• Corase-grained deposits

• Horiz. & cross bedding Debri flow

Channelised

Nichols, 1999

Nichols, 1999


Dune and interdune facies association

Metz et al.,

JSR, 2009

High water table – no aeolian reworking in wet interdune areas

interdune

dune

interdune

dune



• Continental

• Glacial

• Fluvial

• Deserts


• Deltaic


• Estuaries

• Deep marine



barrier

Examples:

Brent, Cook, Upper Tilje (?), Norway


Delta Classification Mississippi

Galloway, 1975

Fluvial-dominated delta subenvironments


Mississippi

Prodelta:

• Suspended fine-grained sediments

• Plums into deeper water

Delta plain:

• Various channel fills

• Crevasse splays

• Floodplain facies (peat)

Interdistributary bay:

• Low energy

• Similar to floodplain

• Bay fill by crevasse splays

bay

Distributary channel:

• Similar to fluvial channel

• Subaqueous levees

Mouth bars:

• Proximal sandy bars

• Not continuous

• Tabular horizontal and cross-bedding

Stets & Schafer, 2009

• Low wave and tide energy

• Deacrese of velosity at the sea front

• Mouth bar – distributive pattern

• Decrease grains side with depth

Delta lobe switching


• Each distributary fills the space and migrates to another location

Nichols, 1999


Wave-dominated delta subenvironments

http://www.seddepseq.co.uk/DEPOSITIONAL_ENV/Deltas/deltas.htm

Prodelta:



Delta plain:


• Crevasse splays

• Floodplain facies

Distributary channel:

• Similar to fluvial channel

• No subaqueous levees

• Do not prograde into the sea

Mouth bars:

• Proximal sandy bars

• Wave/tides reworking

• Tabular horizontal and

cross-bedding

Coastal sandy bars:

• Sandy beaches

• Continuous

• Sand of mouth bars

reworked by oblique waves

• High wave energy

• Difference:

• Channel do not prograde

• Sandy coastal bars

• Well-sorted sand

MSN Map

Paraibo delta, Brazil


Tide-dominated delta subenvironments

Prodelta:



Upper delta plain (non tidal):


• Crevasse splays

• Floodplain facies

Lower delta plain (tidal):

• Tidal flats

• Periodically flooding with tides

• Mangroove

Tidal sand bars:

• Tide modifies mouth bars

• Elongate bars

• Bidirectional cross-bedding

• Mud drapes

Tidal channels:

• Affected tides

• Stagnation periods

• High tidal range

• Difference:

• Channel affected by tides

• Tidal sandy bars

• Tidal indicators

Ganges Delta, Bangladesh / India


Delta progradation

• All types of deltas are progradational in nature

• Produce shallowing vertical facies succession

B

A well well log

prodelta

delta

front

delta plain A B

River-dominated

Delta

plain

Distributary

Channel

Mouth

bar

Delta

front

Prodelta

Nichols, 1999



• Continental

• Glacial

• Fluvial

• Deserts


• Deltaic


• Estuaries

• Deep marine



barrier

Examples:

Rannoch/Etive/Tarbert (Brent Gr), Upper Ile, Norway

Wave-dominated linear shoreline (non-barrier)


• Beach (foreshore, backshore, dunes) – low angle/horizontal bedding

• Shorface (above Fairweather wave base) – dunes, cross bedding

• Offshore transition (above Storm wave base) – hummocky cross stratfication


Wave-dominated linear shoreline with barrier islands

• Abundant sediment supply

• Longshore current

• Small tidal range

• Tidal flat, marsh - small tidal range

• Lagoon – shallow, suspended material from the sea and coastal plain, evaporites

• Washovers – thin layers of sand in lagoon

• Beach (foreshore, backshore) – gravel, sand transported by longshore currents

• Tidal inlet – mesotidal coasts

• Flood and ebb deltas – made up of barrier sediment, dune cross-bedding, onshore direction

• Shorface (above Fairweather wave base)

• Offshore transition (above Storm wave base)

lagoon

Wave dominated shoreline system with barrier islands

MSN Map

Waddel Sea, Germany



• Continental

• Glacial

• Fluvial

• Deserts

• Lacustrine


• Deltaic


• Estuaries

• Deep marine



barrier

Examples:

Lower Tilje, Tarbert, Nordmela, Norway

Estuary types

Western Germany, Google Earth

tide


Seocheon Tidal Flat, Korea, http://www.ramsar.org/

Bride Brook salt marsh, Wikipedia

Saltwater

marsh

Tidal flat Barrier bar

Wave-dominated estuary

Bay-head delta


Tide-dominated estuary

Heap et al. 2001

• Tidal channel – meandering, suspension, Heterolithic point bar (HIS)

• Tidal flat – mud flats, salt marshes cut by tidal creeks, periodically flooded

• Tidal sand bars – sand, gravel, bioclasts

• Dune migration, cross-bedding, 2 direct.

• Mud drapes

• Two path ways for edd and flood tides


Tidal Creeks at the southern end of Great Bay

(photo by Ben Kimball, http://www.nhdfl.org/)

Tidal creek

Tidal mudflat Watson’s Creek (http://www.marsh-friends.org/)

http://geologicalintroduction.baffl.co.uk

Tidal bars and channels

http://www.niwa.co.nz/coasts-and-oceans/nz-coast/learn-about-coastal-environments/beach-types/

13-beach-types/reflective-tidal-mud-flats

Tide-dominated estuary
















Bay fill succession

Classifi

cation:

Internal

2013-

02-07

66

Bayhead delta

Marsh

Floodplain/marshes

Channel fill

Bay-head delta

Subbay

Wave-reworked

deposits

• Floodplain/marshes

• Channel fill

• Bay-head delta

• Subbay

• Wave reworked deposits

Classifi

cation:

Internal

2013-

02-20

68

Wave influenced bayfill, 30/9-4



glacial

aeolian lakes

• Continental

• Glacial

• Fluvial

• Deserts

• Lacustrine


• Deltaic

• Linear shorelines

• Estuaries

• Deep marine



Debri flows

Turbidity currents

Exmaples:

Peregrino, Brazil,

Tanzania, Angola,

King Lear, Åsta Hansteen, Norway


Slope elements and sediment source

Canyons on the shelf slope may be

connected to river source

Wikipedia

Monterey Bay Aquarium Research Institution (MBARI)

Slump on the shelf slope

http://geologycafe.com/landslides/big/25.html


Basin floor

• Submarine fan

• Sediment from canyons

• Spreads out on the lower gradient plain

• Lobes forming fan


http://research.ncl.ac.uk/caprocks/gallery.htm

http://nhm2.uio.no/norges/litho/balder.php

• Hemipelagic deposition

• fine-grained sediment slowly accumulated on

a basin floor

• Pelagic deposition

• microscopic, calcareous or siliceous shells

of phytoplankton or zooplankton

• Mixture of those

Basin floor


Deep-marine submarine fan facies association

http://csmres.jmu.edu/geollab/fichter/SedRx/subfan.html

http://www.geocaching.com

• Canyon – bypass

• Proximal fan

• Channel fairways – Tab – HDT plus debrites

• Levees – Tce,Tde - LDT

• Lobes – Tae,Tbe - LDT

• Distal fan

• Frontal splays – Tcde,Tde – LDT

• Hemipelagic/pelagic deposits



Ainsa, A.Rittersbacher, Troll field course manual

Nichols, 1999

Ainsa, A.Kulikova

Ainsa, A.Rittersbacher, Troll field course manual


Inner fan.

Channel filled with thick conglomerate and

sandstone turbidites, HDT+debrites

Inner fan.

Thin-bedded levee deposits, LDT

Mid-fan.

Channel on lobe filled with HDT or LDT + debrites

Mid-fan.

Coarsening-up succession of sandy turbidites

Distal fan.

Thinly bedded fine-grained turbidites


Nichols, 1999


Sand injectites

• Seals and dykes of re-mobilised unconsolidated sands that were forced upward through

overlying impermeable layers.

• Associated with deep-water clastic systems – Parent sand body

• Intrusive traps (could follow faults or bedding)

• Enhance reservoir connectivity especially vertically - Seal risk / migration paths

Thin-bedded turbidites and sandstone dikes, El Chingue Bluff,

southern Chile (© 2010 clasticdetritus.com)

http://nhm2.uio.no/norges/litho/rogaland.php


Sand injectites

• Could be large - detectable on seismic – strange geometries

• Not necessarily connected to parent body

• Sand injectites are widespread in Paleocene to Pleistocene sediments in the North Sea.

• The sand injectite play is proven by several oil fields; e.g., Grane, Balder, Alba, Volund and

Mariner/Bressay.



glacial

aeolian lakes • Continental

• Glacial

• Fluvial

• Deserts


• Deltaic


• Estuaries

• Deep marine



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3. depositional environments · • similar to fluvial channel • subaqueous levees mouth bars:...

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