Basin Analysis Ch1 Basin & Their Plate Tectonic Environtment Lsu

8/8/2019 Basin Analysis Ch1 Basin & Their Plate Tectonic Environtment Lsu

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Basin Analysis

Chapter1: Basins and their platetectonic environmentThis presentation contains illustrations and

some text from Allen and Allen (2005 ) aswell as illustrations from Press et al.(2004)


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Basins

INTRODUCTION

Definition and examples(What is a basin?)

How are basins classified?

Essay (due next Thursday, barring days off for hurrican

Gustav)

MAKEUPof the

EARTH

Compositional division

Rheological

division

BASIN FORMING MECHANISMS

Plate Tectonics

Thermal

Thermo-mechanical

Mechanical


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Basins

Definition and examples


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Basins

Definition

Areas of the earth where there is a net sedimentation,or in the fossil (ancient) record of such areasZones of pronounced subsidence where sediment canaccumulate.

What makes a basin interesting for oil and gasexploration?

Examples

Gulf of Mexico (today and ancient)Pyrenees (ancient)

Oman (oil from 650 Ma stromatolites

still in livingposition)


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Pre- Cambrian

Permian

Permian-Pre-Cambrianangular unconformity, Oman


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Basins

INTRODUCTION



Homework # 1.A (due next Thursday)

MAKEUPof the

EARTH


Rheological

division


Plate Tectonics

Thermal

Thermo-mechanical

Mechanical


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Basin can be classified according to many priorities of the individual. Aclassification scheme should not just create "order from the chaos", buthighlight patterns that are useful for predicting stratigraphy, andfaulting.

Dickinson's (1974) classification scheme is based on tectonic history:(a) lithospheric

substratum: oceanic versus continental(b) proximity of the basin to a plate margin(c) type of plate margin nearest the basin i.e., convergent, divergent,

conservative (similar to Bally and Snelson, 1980)

Other factors used are: hydrocarbon characteristics, types of sedimentarysequences filling the basin, and the tectonics that modify the sedimentinfill

If on the other hand one is interested in WHERE

they are to be found withrespect to PLATE TECTONIC boundaries we might also get a hint about

the mechanism of formation.

Fossil basins may no longer be in the platetectonic setting in which they were originally formed..


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If one is interested in HOW

Basins are formed then it is very natural thatwe break up the basin types according to their mechanism of formation.E.g., mechanical, thermal or thermal-mechanical.


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Basins

INTRODUCTION




MAKEUPof the

EARTH


Rheological

division


Plate Tectonics

Thermal

Thermo-mechanical

Mechanical


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Homework due next Thursday

Essay

For the basin you have chosen to write a proposal in this class write an

essay (1 page or 300 words

at most, including figures).

In the essay you will classify your basin according to Kingston et al., (1983a) scheme(4-5 sentences).

You should read Ch.1 of your book and the originalpaper to get a detailed understanding of their classification

scheme. (This scheme was devised to help predict hydrocarbonpotential). Write a brief sentence or two about your opinion of thisclassification scheme?

Does it help you?

Does it make it more difficultto understand the basin? Please justify your answer with areason.

Reason your case with evidence and write clearly in your ownwords. Propose an alternative classification of your basin, if needed.

Kingston, D.R. Dishroon,C.P. and Williams,P.A. (1983) Global basinclassification.

Bull. Am. Assoc. Petrol. Geol. 67, 2175-2193.

There isalso a *.pdf

file of this paper available from my website.
http://../Readings/ListofPapers.htmhttp://../Readings/ListofPapers.htmhttp://../Readings/ListofPapers.htmhttp://../Readings/ListofPapers.htm


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Basins

INTRODUCTION




MAKEUPof the

EARTH


Rheological

division


Plate Tectonics

Thermal

Thermo-mechanical

Mechanical


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Basins

MAKEUPof the

EARTH

Compositional subdivision

Crust10-70 kmthick

cont.

granite

2.7 g/ccoceanic- basaltic

>2.8 g/cc

mantleMantleperidotite

>3.1 g/ccdown to2900 kmdepth


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Where is the Moho

deepest?

Where is the Moho

the

shallowest?

Where are there basins?

Allen and Allen (2005)


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Compositional zonation

Based only on the composition, which affects density, and short- term rigidity (and hence seismic velocities) the shallow portionsof the earth (0-80 km) can have one of three flavors:

oceanic composition, i.e. gabbroic melt and all its coolingderivatives-

mafic

rocks, density ~ 2,800 kg/m3, Vaverage

Vp=5km/s

continental composition, i.e. granitic

melt and all its coolingderivatives -

felsic

rocks, density ~ 2,700 kg/m3, average Vp

=

6.5 km/s

mantle i.e. peridotite

and high temperatures and pressures,density = 3,300 kg/m3, average Vp>=8.1 km/s


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Basins

MAKEUPof the

EARTH

Rheological

divisions

asthenosphere

lithosphere

RIGID

DUCTILE


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Key parts of Plate Tectonics

Lithosphere or rigid lid that holds bothcrust and cold mantle together as one

solid block (0-100km)asthenoshphereasthenoshphere

oror plastic,ductileplastic,ductile , layer also, layer also

within the mantle (100km depth to 300within the mantle (100km depth to 300km depth??)km depth??)

C i f i h


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Comparison of views earth structure

crust

mantleMantle

asthenosphere

lithosphere

RIGID

DUCTILE


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Plates

Group of rocks all moving in the samedirection

Can haveboth

oceanic and continentalcrust or just one kind.


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Earth Divisions

What type of subdivisions are being used in these diagrams from Allenand Allen (2005)?


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Basins

Definition and examples

INTRODUCTION

What is a basin?


Essay (due next Thursday)

MAKEUPof the EARTH

Compositional zonation

Rheological

zonation


Plate Tectonics

Thermal

Thermo-mechanical

Mechanical


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Plate TectonicsWhat drives plate tectonics?


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Driving Mechanism ofPlate Tectonics

GRAVITY

Convection may have overturned asthenosphere

46

times.

Convection may initiate process but cooling leads todensification and plate movement.

A cold planet is a dead planet. Is there oil on Mars?


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Ridge Push and Trench

Pull

Press et al., 2005

T M d l f M tl


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Two Models of Mantle

Convection

Press et al. 2004

Divergent Plate Boundary


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Divergent Plate BoundaryUsually start within continentsgrows to become ocean basin

Press et al. 2004


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Basins


Thermal (lithospheric

thermal erosion, plumes (active upwelling)

as well as cooling)

Thermo-mechanical (cooling leading to subsidence)

Mechanical (e.g.,regional

isostasy

(sub-

super-crustal),aestenospheric

drag, crustal

extension)

Link to composition of N.American

Plate

Link to thermal structure of N. American Plate
http://images.google.com/imgres?imgurl=http://prodev.iris.edu/Figure2/gilbert.jpg&imgrefurl=http://prodev.iris.edu/Accomplishments.htm&h=100&w=250&sz=38&hl=en&start=47&sig2=PvNetKWJWfVmfrXecJtlWw&um=1&usg=__UPKRItymL4HYmz1r7xnUFPVxScg=&tbnid=tEEK4EPMyrw20Mhttp://images.google.com/imgres?imgurl=http://prodev.iris.edu/Figure2/gilbert.jpg&imgrefurl=http://prodev.iris.edu/Accomplishments.htm&h=100&w=250&sz=38&hl=en&start=47&sig2=PvNetKWJWfVmfrXecJtlWw&um=1&usg=__UPKRItymL4HYmz1r7xnUFPVxScg=&tbnid=tEEK4EPMyrw20Mhttp://images.google.com/imgres?imgurl=http://prodev.iris.edu/Figure2/gilbert.jpg&imgrefurl=http://prodev.iris.edu/Accomplishments.htm&h=100&w=250&sz=38&hl=en&start=47&sig2=PvNetKWJWfVmfrXecJtlWw&um=1&usg=__UPKRItymL4HYmz1r7xnUFPVxScg=&tbnid=tEEK4EPMyrw20Mhttp://images.google.com/imgres?imgurl=http://prodev.iris.edu/Figure2/gilbert.jpg&imgrefurl=http://prodev.iris.edu/Accomplishments.htm&h=100&w=250&sz=38&hl=en&start=47&sig2=PvNetKWJWfVmfrXecJtlWw&um=1&usg=__UPKRItymL4HYmz1r7xnUFPVxScg=&tbnid=tEEK4EPMyrw20Mhttp://images.google.com/imgres?imgurl=http://prodev.iris.edu/Figure2/gilbert.jpg&imgrefurl=http://prodev.iris.edu/Accomplishments.htm&h=100&w=250&sz=38&hl=en&start=47&sig2=PvNetKWJWfVmfrXecJtlWw&um=1&usg=__UPKRItymL4HYmz1r7xnUFPVxScg=&tbnid=tEEK4EPMyrw20Mhttp://images.google.com/imgres?imgurl=http://prodev.iris.edu/Figure2/gilbert.jpg&imgrefurl=http://prodev.iris.edu/Accomplishments.htm&h=100&w=250&sz=38&hl=en&start=47&sig2=PvNetKWJWfVmfrXecJtlWw&um=1&usg=__UPKRItymL4HYmz1r7xnUFPVxScg=&tbnid=tEEK4EPMyrw20Mhttp://images.google.com/imgres?imgurl=http://prodev.iris.edu/Figure2/gilbert.jpg&imgrefurl=http://prodev.iris.edu/Accomplishments.htm&h=100&w=250&sz=38&hl=en&start=47&sig2=PvNetKWJWfVmfrXecJtlWw&um=1&usg=__UPKRItymL4HYmz1r7xnUFPVxScg=&tbnid=tEEK4EPMyrw20Mhttp://images.google.com/imgres?imgurl=http://prodev.iris.edu/Figure2/gilbert.jpg&imgrefurl=http://prodev.iris.edu/Accomplishments.htm&h=100&w=250&sz=38&hl=en&start=47&sig2=PvNetKWJWfVmfrXecJtlWw&um=1&usg=__UPKRItymL4HYmz1r7xnUFPVxScg=&tbnid=tEEK4EPMyrw20M


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The Rock

Cycle

Press et al. 2004


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Rock Cycle

Igneous rocks originate from magma. These rocks are subsequently eroded to form sediments that are transported and deposited in

basins and can be preserved within continents

Why is there a rock cycle?


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Allen and Allen, 2005

Diachrono s Appalachian


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Diachronous Appalachian

Orogenic events

Taconic (Ordovician) All Appalachians

Acadian (Devonian) Mostly in northern

Appalachians

Alleghanian

(Late Carboniferous- Permian) Mainly in the southern

Appalachains

Basin Analysis Ch1 Basin & Their Plate Tectonic Environtment Lsu

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Transcript of Basin Analysis Ch1 Basin & Their Plate Tectonic Environtment Lsu