This document summarizes the tectonic setting and geology of the Sumatra region in Indonesia. It describes how Sumatra is located along several major tectonic plate boundaries, including the Great Sumatra Fault zone. It outlines the plate tectonics movements that have shaped Sumatra, including convergence, divergence, and transvergence. It also describes the major tectonic elements of Sumatra, including the Sunda Shelf, Bukit Barisan mountain range, and Sumatra Trench. Furthermore, it summarizes the pre-Tertiary basement rocks, Tertiary sedimentary basins, and major fault systems of Sumatra, including the Trans Sumatra strike-slip fault system and Paleogene basement fault

1. GEOLOGI REGIONAL SUMATERA

3. Sukamto(2000)

4. Tipe Pembentukan Gunung
Convergent Boundaries : (a) oceanic vs continent, (b)
oceanic vs oceanic, (c) continent vs continent
Press and Siever (1998)

5. Convergent Boundaries : (a) oceanic vs continent (Subduction), (b) continent
vs continent (collision)
Press and Siever (1998)

6. Physiography of Indonesia

8. Sukamto(2000)

9. Katili(1973)
Present Plate Boundaries in South East Asia

10. Indonesia Tectonic Boundary
• West : Great Sumatra and Mentawai duplex mega-shears, Sumatra Trench
• South : Java Trench-Timor-AruTrough
• East : ArafuraPlatform (Australia Craton)
• North : SorongFault, North SulawesiTrench, SCS (South China Sea)
Plate Tectonics Movement In Indonesia Involves :
• Convergence, (collisions, subductionand obduction)
• Divergence (rifting, break-up and subsequent seafloor spreading)
• Transvergence(wrench faulting) involving translation and rotation
Plate tectonics subdivision of indonesia
• West Indonesia with Sunda Platform acting as a continental core
• Central Indonesia consising of fragmented microcontinents represented by
Sulawesi and the Banda Arc
• East Indonesia with the Arafura Platfrom acting as a continental core

11. Tectonic Framework of Indonesia

12. Stratigraphy of Indonesia

13. Sukamto(2000)

14. Sukamto(2000)

21. SUMATRA MAJOR TECTONIC ELEMENTS
• The SundaShelf borders the back arc basin to the east
• AsahanArch, BukitTigapuluhMountains and LampungHigh
partitions the back-arc basins
• The BukitBarisanRange : NeogeneMagmaticarc, separates
the back-arc basins from West Sumatra fore-arc basins
• The Outer Arc Islands : accretion wedges
• The Sumatra trench: an oblique subductionzone

22. Sumatra Pre-Tertiary Basement
• Pre Tertiary rocks are exposed in the BarisanRange,
TigapuluhMountains and LampungHigh.
• Sumatra Pre-Tertiary rocks have been analyzed into separate
terranesconsisting of :–highly tectonizedPaleozoic and
Mesozoic terranes–Paleozoic to Mesozoic intrusive rocks–
Melange(ophioliticrocks).
• Pre-Tertiary terranesare interpreted as a collage of Asian and
Gondwananmicrocontinents.

23. Pertamina-Beicip (1985)

24. SUMATRA TERTIARY BASINS
• Back-arc and partly fore-arc basins are underlain by continental
crust.
• The magmaticarc, BarisanRange, uplifted Pre-Tertiary rocks
forms border to the basins.
• Paleogenerift basins extend from back-arc to fore-arc basins
across the BukitBarisan.
• Volcanism is limited to Paleogene(in the Southwest) and Plio-
Pleistocene.
• The presence of the Great Trans-Sumatra wrench fault
(SemangkoFault) along the BukitBarisan.

26. PENAMPANG LINTASAN SW-NE

28. Sumatra Tectono-Stratigraphic System
From top to base :
• Syn-orogenicdeposition in a back-arc basin : regressive
(Mid-Miocene-Recent)–rising BarisanRange
clasticsource
• Post-rift deposition in a shelfalbasin :
transgressive(Early Miocene) –Sundalandclastics source
and carbonates
• Syn-rift deposition in active rift-valley basins : one or
more rift phases (?Eocene-Oligocene)–local
clasticsource

29. Sumatra Major Fault System
THE TRANS SUMATRA STRIKE-SLIP FAULT SYSTEM : active
since Early Tertiary times
• THE PALEOGENE BASEMENT FAULT SYSTEM :
This fault system resulted in the Paleogenegraben-half-
grabensystem with syn-rift deposition
The Sumatra PaleogeneFault System extends SE to the
NW Java basinalarea

31. The PaleogeneBasement Fault System
• This fault system consists of two main components–N-S
component–WNW-ESE component–In South Sumatra a NE-
SW component is present
• This fault system cuts clear across the BarisanRange,
beneath the fore-arc basin.
• This fault system is responsible for the development of
Paleogenegraben-half-grabenbasin system with syn-rift
deposition forming important oil kitchens.

34. PaleogeneBasement Faults Explanation
• Moulds (1989): Faults are mainly N-S and was created due to the
E-W directed extensional regime during the initial stage of the N-
S directed stress caused by the subduction.
• Other explanation: transtensionalfaults due to the dextral
wrenching movements of the Indian Ocean Plate relative to the
Sundacontinental plate

35. TERIMA KASIH