04. Tectonics of Indonesia

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Indonesia

Indonesia : a meeting place of the major plates

modif ied from Press and Siever (1998)





Hall (1997)Present Tectonic Configuration of Indonesia

AWANG H. SATYANA - BPMIGAS


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Sukamto (2000)



Sukamto (2000)



Simandjuntak & Barber (1996)

Basement geology and structural setting of Southeast Asia




Katili (1973)



Indonesia : Tectonic Boundary

• West : Great Sumatra and Mentawai

duplex mega-shears, Sumatra Trench

• South : Java Trench-Timor-Aru Trough

• East : Arafura Platform (Australia Craton)

• North : Sorong Fault, North Sulawesi

Trench, SCS (South China Sea)

Awang H. Satyana (2005)



Making of Indonesia (1)

• Indonesia archipelago is a jigsaw puzzle of

tectonically derived pieces, includingmicroplates, continental fragments, mini-

ocean basins, accretionary prisms, andisland arc systems that have been jostled

and squeezed together as a result of thecomplex interaction of three major tectonic

plates.




The Making of Indonesia

Hall (1995)



Making of Indonesia (2)

• Convergence of the Asian Plate (Sunda Shield)

with the continental part (Australian craton) ofthe Australian Plate ultimately defined two major

geological provinces.

• Western Indonesia : southeast margin of the

Sunda Shield.

• Eastern Indonesia : highly fragmented andtectonized northern margin of the Australian

craton.




Pre-Cretaceous Evolution (1)

• Contribution from terrane tectonics.

• The evolution of Indonesia (East and SE Asian terranes)should be looked in the framework of the evolution of

Gondwanaland, Laurasia, Pangaea, and Tethys.

• Detailed information on the movements (particularlycross-latitudinal) of continental blocks and the changing

spatial distribution of seas and oceans provides a basis

for investigating globally important problems.




Terranes

and sutures

of SE Asia


Metcalfe (1996)





Pre-Cretaceous Evolution (2)

• It is now well established that continental SE Asia

comprises a complex assembly of continental terranes.

The pre-Cretaceous terranes now constitute mainland

SE Asia.

• All the SE Asian terranes are interpreted to have beenderived directly or indirectly from Gondwanaland.

• Their Palaeozoic and Mesozoic history involved the

rifting of terranes from the northern margin ofGondwanaland, their northwards drift and

amalgamation/accretion to form proto-SE asia (rift-drift-

suturing). Awang H. Satyana (2005)



Tectonic

reconstruction of

Eastern

Gondwanaland :

Cambrium to Late

Devonian


Metcalfe (1996)



Tectonic

reconstruction of

Tethyan Region :Carboniferous to

Late Triassic


Metcalfe (1996)



Tectonic

reconstruction of

Eastern TethyanRegion : Late

Jurassic to Late

Cretaceous


Metcalfe (1996)



Cretaceous and Cenozoic Evolution

• The Cretaceous and Cenozoic evolution of the small

terranes distributed around the SCS and in EasternIndonesia.

• These include : West Irian Jaya, Buru-Seram, Buton,

Banggai-Sula, Obi-Bacan, North Palawan, SpratleyIslands-Dangerous Ground, Reed Bank, Luconia,

Macclesfield Bank, Paracel Islands, Kelabit-Longbowan,

Mangkalihat, Paternoster, West Sulawesi, EastSulawesi, and Sumba.




Cenozoic SE Asia Reconstruction

Four Major Regional Subsets

1. India-Eurasia collision and its possible displacement of the

constituent blocks of Sundaland (50 Ma, middle Eocene).

2. Development of SCS (32-21 Ma, early Oligocene-Early

Miocene).

3. Motion of the Philippine Sea plate and the Philippine

Islands, collsion of Luzon Arc with the Asian Plate (5 Ma,

basal Pliocene).

4. Development of the Banda Sea region and northern New

Guinea and arc collisions with the Australian craton (8-3

Ma, late Miocene-Pliocene).




Longley (2002)



Tectonic Evolution (1)

• 50-43 Ma (middle Eocene) :

– Slowing of convergence as the Indian subcontinent approachedthe Asian plate.

– Initiation of continental collision.

– Initial stage of rift ing along the Sundaland margin.

– The Bird’s Head of Papua was probably a micro-continental

fragment on the northwest edge of the Australia plate.

– New Guinea represented the passive northern margin of the

Australia craton. – Halmahera Island was still thousands of kms to the east and part

of the Philippine Sea plate.





• 43-25 Ma (middle Eocene-latest late Oligocene) :

– Final collision of the Indian subcontinent to the Asian plate (43.5 or

42.0 Ma).

– Slowing of convergence and change of subduction vector from

northwards to north-northeastwards along the Sunda trench.

– North-south oriented rifting at the edge of the Sunda shield due torelaxation of compressional forces.

– Isolated rifts in forearc setting and in East Java filled with

transgressive and then open marine sediments.

– Fluvio-lacustrine sediments developed in NW Java, Sumatra,Kalimantan, west Sulawesi, and Natuna Sea rifts.

– Opening of the SCS (32-21 Ma).

– Opening of the West Philippine basin, Celebes Sea, and Makassar

Strait.





• 25-8 Ma (latest late Oligocene-late Miocene) :

– Collision of New Guinea passive margin with the Philippine-Halmahera-

New Guinea arc system.

– The Bird’s Head microcontinental fragment was close to collision with themargin of the Sundaland near west Sulawesi. Ophiolites were emplaced

along the eastern edge of this western Sulawesi arm.

– Oceanic crust trapped between Sulawesi and Halmahera was rotated

clockwise and subducted beneath the eastern margin of Sulawesi.

– Continued northward motion of the Indo-Australian plate.

– Counter-clockwise rotation of the entire Sunda shield promontory

including peninsular Malaysia, Sumatra, Java and Borneo.

– Right-lateral movement along the Great Sumatra Fault.

– Separation of West Java from South Sumatra due to rotation and half-graben development in the Sunda Strait.

– Subduction of Halmahera and Philippine plate below north Sulawesi.

– Opening of the Sulu Sea.

– Accretion of fragments of the Australian continental crust along theSorong Fault to eastern Sulawesi.





• 8-0 Ma (late Miocene-Present) :

– Extensive inversion and the formation of compressional anticlines

due to northward subduction of Indian oceanic plate, collision of

the Australian craton, and continuous movement along the Great

Sumatra fault.

– Accretion of the Tukang Besi platform to Sulawesi locked strands

of the Sorong fault, causing new splays to develop south of the

Sula platform and the collision of the Sula platform with Sulawesi.

– Rotation of the east and north arms of Sulawesi to their present

position.

– Southward subduction of Sulawesi Sea beneath north Sulawesi

arm.

– Continued subduction of the northward moving Indo-Australian

plate along the Sunda trench system, extending from northwest

Sumatra to south Papua.




Plate tectonicreconstructions for SE

Asia and Indonesia region

from 50 Ma to 10 Ma

Hall (1995), Hall (1997)



Tectonic periods in SE Asia region Schereus (1996)




Katili (1974)



Simplified tectonic

elements and crustal

distr ibution for Indonesia

Coffield et al. (1993), Nugrahanto and Noble (1997), Netherwood (2000)

T t i f



Tectonics ofIndonesia :

constraints frommantle tomography

Hall and Spakman (2005)

vertical section of P wave

speed to a depth of 2000 km

Maruyama (1999)

Documents

04. Tectonics of Indonesia