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DIVERGENT TECTONICS
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DIVERGENT TECTONICS
LITHOSPHERIC
PLATES
STYLE OF
RELATIVEPLATE MOVEMENT
AND PLATE
INTERACTIONS
DIVERGENT
MAGMATIC
ACTIVITY
STRUCTURAL
STYLE
BASIN
FORMATION
ANDEVOLUTION
ASSOCIATED
TECTONISM
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DIVERGENT TECTONICS
DIVERGENT
MAGMATIC
ACTIVITY
STRUCTURAL
STYLE
BASIN
FORMATION
ANDEVOLUTION
EXTENSIONAL
TECTONIC REGIME
RESULTED IN
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DIVERGENT TECTONICS
DIVERGENT TECTONIC AND
EXTENSIONAL TECTONIC REGIMES
TECTONIC REGIME DEFINITION :
REGION INFLUENCED BY CERTAIN
TECTONIC ACTIVITY
RESULTED IN BULK PROPERTIES
DEPICTING THE BEHAVIOR
OF CERTAIN TECTONIC PROCESSES
STRUCTURAL PATTERN, ROCK ASSOCIATION
RESULTED FROM SEDIMENTATION -
METAMORPHISM AND MAGMATISM
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DIVERGENT TECTONICS
EXTENSIONAL
TECTONIC
REGIME
MAIN SOURCE
OF STRESS
- OCEAN RIDGES
- CONTINENTAL
MARGINS- PLATEAU
UPLIFTS
• FORCES PRODUCED
FROM SUBDUCTION
• DENSITY IMBALANCES
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DIVERGENT TECTONICS
EXTENSIONAL TECTONIC REGIME
AREASSOCIATED WITH
DIVERGENT PLATEINTERACTION
CONVERGENT PLATEINTERACTION
OCCURING AT
PLATE MARGINS
( PLATEBOUNDARY)
INTRA PLATE
AS WELLAS
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EXTENSIONAL TECTONIC REGIME
ASSOCIATED WITH
CONVERGENT PLATE
INTERACTION
COMMONLY FOUND AT
PLATE MARGINS
( PLATEBOUNDARY)
INTRA PLATE
FRONT AND
INTRA MAGMATIC ARC
BEHIND
MAGMATIC ARC
OCCUPIES
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PLATE TECTONIC SETTING OF EXTENSIONAL SYSTEM
BACK-ARC
RIFTINGCONTINENTAL
AND OCEANIC
RIFTING
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A) Domino
B) Listric
C) ImbricateD) Listric and Planar
Hill, 2003
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1. OCEAN RIDGES
2. CONTINENTAL RIFTS
OF TYPE - I
3. CONTINENTAL EXENSIONALAT CONVERGENT BOUNDARY;
BACK-ARC EXTENSIONAL
4. STRIKE-SLIP EXTENSIONAL
1. CONTINENTAL RIFTS
OF TYPE-II
2. INTRAPLATE EXTENSIONAL
BASINS
PLATE BOUNDARY
REGIMES
INTRAPLATE
REGIMES
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DIVERGENT TECTONICS
1. OCEAN RIDGES
2. CONTINENTAL RIFTS
3. CONTINENTAL EXENSIONALAT CONVERGENT BOUNDARY;
BACK-ARC EXTENSIONAL
4. STRIKE-SLIP EXTENSIONAL
PLATE BOUNDARY
REGIMES
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MOR CH R CTERISTICS
DIVERGENT TECTONICS
1. TOPOGRAPHY (≈1000 km) broad ridges with narrowcentral rifts.
2. BASALT VOLCANISITY mostly tholeitic composition
3. HIGH HEAT-FLOW
4. NEGATIVE GRAVITY ANOMALIES (melts)
5. SEISMIC ACTIVITY (mainly shallow earthquakes)
6. MAGNETIC ANOMALIES oriented parallel with the
ridges
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DIVERGENT TECTONICS
1. OCEAN RIDGES
2. CONTINENTAL RIFTS
3. CONTINENTAL EXENSIONALAT CONVERGENT BOUNDARY;
BACK-ARC EXTENSIONAL
4. STRIKE-SLIP EXTENSIONAL
PLATE BOUNDARY
REGIMES
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DIVERGENT TECTONICS
1. OCEAN RIDGES
2. CONTINENTAL RIFTS
3. CONTINENTAL EXENSIONALAT CONVERGENT BOUNDARY;
BACK-ARC EXTENSIONAL
4. STRIKE-SLIP EXTENSIONAL
PLATE BOUNDARY
REGIMES
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DIVERGENT TECTONICS
1. OCEAN RIDGES
2. CONTINENTAL RIFTS
OF TYPE - I
3. CONTINENTAL EXENSIONAL
AT CONVERGENT BOUNDARY;BACK-ARC EXTENSIONAL
4. STRIKE-SLIP EXTENSIONAL • DIP SLIP DISPLACEMENT
CHARACTERIZED THE
FLANKING FAULT SCARPS
• MAKES UP 32.7 % OF THE
SURFACE AREA
• HIGH HEAT FLOW ALONG
THE RIDGE AXIS
• THE PRESENCE OF
ASTHENOSPHERIC MANTLECLOSE TO THE SURFACE
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DIVERGENT TECTONICS
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DIVERGENT TECTONICS
1. OCEAN RIDGES
2. CONTINENTAL RIFTS
3. CONTINENTAL EXENSIONAL
AT CONVERGENT BOUNDARY;BACK-ARC EXTENSIONAL
4. STRIKE-SLIP EXTENSIONAL• DIP SLIP DISPLACEMENT
CHARACTERIZED THE
FLANKING FAULT SCARPS
INDICATE EXTENSIONNORMAL TO RIFT AXIS
DIFFERENCE IN
SPREADING RATE
ACCOMMODATE BY SHORT
TRANSFORM FAULTS
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DIVERGENT TECTONICS
EXTENSIONAL
AT CONVERGENT
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DIVERGENT TECTONICS
BACK-ARC BASIN AS EXTENSIONAL AT CONVERGENT
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DIVERGENT TECTONICS
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DIVERGENT TECTONICS
2. CONTINENTAL RIFTS
OF TYPE - I
• CLASSIFICATION
• ORIGIN
• ACTIVE RIFT
-CONSTRUCTIVE
PLATE BOUNDARY
- INTRA PLATE
• INACTIVE RIFT -FAILED ARMS;
( AULACOGEN )
• MANTLE ACTIVATED
• LITHOSPHERE ACTIVATED
(CONDIE, 1982)
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DIVERGENT TECTONICS
• ACTIVE RIFT
-CONSTRUCTIVE
PLATE BOUNDARY
- INTRA PLATE
EAST AFRICAN -
RED SEA – GULF OF ADEN
RIFT
LINKS WITH INDIAN OCEAN
MODERN ANALOUGE
WITH RIFT SYSTEM
WHICH RESULTEDIN THE BREAK UP
OF PANGEA
FLOORED BY OCEANICCRUST;
COMMENCED OPENING
LATE MIOCENE
DIVERGENCE RATE
2 CM/Y
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DIVERGENT TECTONICS
• ACTIVE RIFT
-CONSTRUCTIVE
PLATE BOUNDARY
- INTRA PLATE
RHINE GRABEN (RIFT)
DUE TO ALPINE
OROGENY
• COMMENCE IN L.CRETAC.
• EOC.-OLIG0. RIFTING AND SUBSID.
• MIO.-PLIO. EXTENSION DECREASED
• M.PLIO. REACTIVATION TO SINISTRAL SH.
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INTRACONTINENTAL EXTENSION
1. BRITTLE-DUCTILE TRANSITION AND
SUB-HORIZONTAL DECOUPLING
2. CRUSTAL-PENETRATING LOW-ANGLE
NORMAL FAULT
3. HYBRID MODEL
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DIVERGENT TECTONICS
2. CONTINENTAL RIFTS
OF TYPE - I
• ORIGIN
• MANTLE ACTIVATED
• LITHOSPHERE ACTIVATED
(CONDIE, 1982)
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DIVERGENT TECTONICS
2. CONTINENTAL RIFTS
OF TYPE - I
• MANTLE ACTIVATED
(BURKE AND DEWEY, 1973)
RIFT
CRUST
LITHOSPHERE
ASTHENOSPHERE
# DOMAL UPLIFTCAUSE OF
RIFTING
MANTLE PLUME(“DIAPIR”)
# ABUNDANT VULCANICITY
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DIVERGENT TECTONICS
2. CONTINENTAL RIFTS
OF TYPE - I
• ORIGIN
• MANTLE ACTIVATED
• LITHOSPHERE ACTIVATED
(CONDIE, 1982)
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DIVERGENT TECTONICS
2. CONTINENTAL RIFTS
• LITHOSPHERE ACTIVATED
(CONDIE, 1982)
CRUST
LITHOSPHERE
ASTHENOSPHERE
RIFT
# EXTENSIONAL
STRESS MAXIMUM
DURING BREAK-UP
OF CONTINENT
COMMENCE WITH
GRABEN AND BASIN
# VULCANISM AT LATER STAGE
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DIVERGENT TECTONICS
2. CONTINENTAL RIFTS
• MANTLE ACTIVATED
(BURKE AND DEWEY, 1973)
CRUST
LITHOSPHERE
THE EAST AFRICAN RIFT
SYSTEM;
RIFT
CONNECTED VIA AFAR
TRIPLE JUNCTION WITH
THE RED SEA – GULF OF
ADEN
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DIVERGENT TECTONICS
• MANTLE ACTIVATED
(BURKE AND DEWEY, 1973)
THE EAST AFRICAN RIFT
SYSTEM;
CONNECTED VIA AFAR
TRIPLE JUNCTION WITH
THE RED SEA – GULF OF
ADEN
TO THE WEST LINK WITH
THE ATLANTIC
# ASSOCIATED 3 DOMAL UPLIFT
AS CENTRES OF ALKALINE
VULCANICITY
ACROSS
CENTRAL AFRIKA
TO 2 DOMAL UPLIFT
DARFUR AND ADAMAOUA
BY MEANS OF 2 RIFTS :
• ABU GABRA AND
• NGAONDERE
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DIVERGENT TECTONICS
EAST AFRICAN
RIFT SYSTEM
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DIVERGENT TECTONICS
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DIVERGENT TECTONICS
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DIVERGENT TECTONICS
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DIVERGENT TECTONICS
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DIVERGENT TECTONICS
“DIVERGENT
TECTONIC REGIME”
TERJADI DI WILAYAH
PUNGGUNG
TENGAN SAMUDRA
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DIVERGENT TECTONICS
TIPE
PASIVE CONTINENTAL
MARGIN BASIN
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DIVERGENT TECTONICS
PERKEMBANGAN LENGKAP DARI
DIVERGENT CONTINENTAL MARGIN
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EXTENSIONAL FAULT STYLES
A. CRUSTAL EXTENSIONAL FAULT SYSTEMS
1. Intracontinental Rift Systems – Dominantly Planar Arrays
2. Passive Continental Margins – Dominantly Planar Arrays
3. Mid-Ocean Ridge Systems – Planar
4. Back-Arc Basins – Planar
5. Extensional Collapse Basins – Low-angle Planar and Listric6. Strike-Slip Pull-Apart Basins – Dominantly Planar
B. DETACH EXTENSIONAL FAULT SYSTEM
1. Propagrational Delta Systems – Listric Arrays
2. Passive Continental Margins – Dominantly Listric
3. Salt Detachment and Diapirs – Dominantly Listric
4. Submarine Scrap Collapses – Listric
After McClay (1996)
RIFT BASIN NOMENCLATURES
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RIFT BASIN NOMENCLATURES
•
TECTONO-STRATIGRAPHY