GOP Flashcards
Surrounded by 3 major plates
Philippine Mobile belt
the 3 plates surrounding the Philippine Mobile Belt?
- Pacific Plate
- Eurasian Plate
- Indo-Australian plate
The Pacific Plate is moving ______ at ______ per year.
Northwest , 80mm
The Eurasian Plate is moving ______ per year
3mm
the fastest moving plate
Indo-Australian plate
Indo-Australian plate moves _______ at _______mm/yr
Northward motion, 107
Eurasian Plate is composed of
Entirely continental crust except at the marginal basin
Pacific Plate is composed of
Oceanic crust
Fixed / stable plate since 50 Ma (late miocene)
Eurasian plate
Age of Pacific Plate
150 Ma (Late Jurassic)
Evidence used to identify the rotation/ manifestation that happened 25 MY
Emperor Seamount
Why does the Pacific Plate only age up to 150 MY?
Because the material there are being SUBDUCTED
Kinematics reorganization of the Pacific Plate happened during
- 43 MY (eocene) at 5° Counter clockwise (NNW to WNW)
- 5 MY (miocene) at 10° Clockwise
2 components of the Indo-Australian plate
Continental and Oceanic
The continental component of Indo-Australian plate
India and Australia
The oceanic component of Indo-Australian plate
Indian Ocean
Australia and India separated because?
The development of MOR
The separation of Australia and India started _______ and cease during ______
150 MY (Late Jurassic) (start) ; 43MY (Middle Eocene) (end)
Pacific Plate subducts at
- Under Eurasian plate along Japan trench
- Along Bonin-Marianas Yap trench system; under Philippine Sea plate.
- Under Indo-Australian, east of New Zealand.
The India part of the Indo-Australian plate collides with
Eurasian plate (in the Himalayas)
The Philippine Sea Plate is subdivided to
- Ocean Basin
- Submarine Ridges
West Philippine Basin is composed of
3 submarine plateau
3 submarine plateau in the West Philippine Basin
- Benham Rise
- Urdaneta Plateau
- Anami oki-daito ridges
Base on _________, West Philippine Basin is age 35 MY to 60 MY
Paleomagnetic Data
West Philippine Basin is age 42 to 53 MY based on
Deep sea Drilling
The oceanic portion of Indo - Australian Plate subducts under Eurasian Plate along the ____________
Java Trench
Occupies almost 50% of the Philippine Sea Plate
West Philippine Basin
An extinct MOR in the WPB
Central Basin Fault
Central basin fault trends from ________ to _______
WNW to ESE
The one responsible for the spreading or generation of the WPB
Central Basin Fault
Stages of Opening of WPB
- 60 and 45 MY at NE-SW (4.4 cm/year of half spreading rate)
- 45 and 35 MY at NS orientation (1.8 cm/yr)
2 models for the WPB’s Origin
- Trapped Oceanic Basin
- Back Arc Basin
Trapped Oceanic Basin states that
WPB is enclosed by older ridges
Back Arc Basin Model states that
As subduction goes along, if the slab is older and colder it will therefore be pushed back or roll back because it gets heavier and as it rolls back it pulls/ trigger the spreading of the central basin faults which causes the generation of the WPB
The Philippine Island is located at
Philippine Mobile Belt
During the Opening of the WPB the _________ correspond to a relict volcanic arc that travelled to the NE. (According to Back Arc Basin Model)
Oki - Daito
An Oceanic Crust Basin that accelerates on a N-S spreading axis
Parece Vela - Shikoku Basin
The 1st Stage of the opening of the PVSB starts at ______ and correspond to ________
30 Ma ; Parece Vela
The 2nd Stage of the opening of the PVSB starts at ________ and correspond to ________
10 Ma; Shikoku
The PVSB stops it movement at
17 Ma
It is a presently active Basin and opens around 6 Ma
Marianas Basin
The Opening of the MB is usually associated with
an eastward migration of the subduction of the Pacific Plate under the Philippine Sea Plate
Poorly known portion on the Southern extremity of the PSP
Ayu Basin
It divides the WPB and the PVSB
Palau - Kyushu Ridge
Palau - Kyushu Ridge traverse the PSP for _________ km
2500 km
Palau - Kyushu Ridge is considered as a relic volcanic arc of the _________ to _________ age
Middle Eocene to Oligocene
Following the Trapped Basin Model the Palau - Kyushu Ridge what happened at 43 Ma
Transform fault to subduction
Following the Trapped Basin Model the Palau - Kyushu Ridge what happened at 30 Ma
the subduction retreated eastward
Eastern limit of the Shikoku Basin
Izu - Bonin Ridge
Izu - Bonin Ridge Represent the volcanic arc of the present active __________ colliding with the ____________
Bonin Trench ; Japanese Margin (Izu Peninsula)
Two branches of Izu - Bonin Ridge towards south
- West Marianas Ridge
- East Marianas Ridge
An ancient volcanic arc active between 20 to 9 Ma
West Marianas Ridge
Volcanic Arc of the presently active Marianas Trench
East Marianas Ridge
Defines the W and E limits of Marianas Basin
East Marianas Ridge
Tectonic Nature of the Boundaries of the PSP
- To the E, defined by the Bonin – Marianas – Yap
Trench system - To NW, subducts under the Japanese Archipelago
along the Nankai and Ryukyu Trench - Collides with the Eurasian Margin in Taiwan
- To SW, subducts into Philippine Archipelago along
Philippine Trench System
Present Day Kinematics of the PSP
NW displacement direction
3 Main Kinematic parameters of PSP with Respect to Eurasia
- Rotation pole located NE of Japan
- Relative displacement rate that varies from N to
S along the western edge of the PSP, from 3
cm/yr in the latitude of the Nankai Trough to
around 9 cm/yr on the southern end of the
Philippine Trench - Relative displacement direction whose azimuth is
directed N55W near Taiwan with a linear velocity
around 7 cm/yr
The reorganization of the Old Kinematics of the PSP happened
4 Ma
The Marginal Basins that has an affinity with the Eurasian Plate
- South China Sea Basin
- Sulu Sea Basin
- Celebes Sea Basin
South China sea has a depth of
4km
South China Sea opened during
32 and 17 Ma
The opening of South China Sea was preceded by
Rifting
The rifting that happened after the opening of South China sea could have take place
Between late Cretaceous and Late Eocene
2 stages of opening in South China Sea
- 32 to 17 Ma; along E-W axis
- 20 to 17 Ma ; along NE-SE axis
Situated immediately to the Southeast of Palawan.
Sulu Sea Basin
Composed of two sub-basin that are separated by an E-NE trending the Cagayan de Sulu ridge
Sulu sea Basin
Located at SE of Sulu Basin and Aulu-Zamboanga Arc.
Celebes sea basin
Has an age of Eocene age (around 55 to 42Ma) based on the ENE-WSW oriented magnetic anomalies
Celebes Sea Basin
The assigned age of Celebes Sea Basin was supported by
Results of Radiolarian dating of Pelagic Sediments
West dipping Subduction zone.
Philippine Trench and East Luzon Through
East dipping Subduction zone
Manila trench, Negros trench, and Cotabato trench
Responsible for the volcanic arc traced from Bicol to Leyte
Philippine Trench
Westward Subduction of PSP under them eastern Philippine arc
Philippine Trench
Presently shows signs of movement
East Luzon trough
Subduction of the oceanic crust if S. China sea under the Luzon Arc
Manila trench
Oceanic crust of the Sulu Sea Basin is being consumed
Negros trench
It’s subduction is marked by the presence of an arc.
Negros trench
A left lateral strike slip fault in Mindanao that links the Cotabato Trench and negros trench
Cotabato fault.
Consumes the celebes sea basin, and the corresponding volcanic arc can be found on the Western margins
Cotabato Trench
The Geology of the PMB is subdivided to
- Metamorphic Rocks
- Ophiolites and Ophiolitic Belts
- Magmatic Arcs
- Sedimentary Basins
Pre - Cretaceous Metamorphic Rocks of Continental Origin:
- Carmaoy Schist
- Halcon Metamorphics
- Romblon Metamorphics
- Buruang Metamorphics
- Tungauan Schist
Cretaceous Metamorphic Rock of Insular Arc Affinity:
Basic to Ultramafic in character
The Pre – Cretaceous Metamorphic Rocks of Continental Origin is characterized by __________ and concentrated on the _________________
high Silica ; Western Portion of the Philippines
The Cretaceous Metamorphic Rock of Insular Arc Affinity do not extend beyond ___________
Paleogene
Complete Ophiolites
- Zambales
- Isabela
- Palawan
- Pujada
Youngest Ophiolite
Mindoro (Amnay)
Oldest Magmatic Arc
Cebu (Cretaceous)
Ages of the ancient magmatic arc in the Philippines
- Cretaceous
- Early Eocene to Oligocene
- Middle Miocene to Late Miocene
- Miocene to Pliocene
- Plio - Pleistocene
Active Volcanic Arcs
- Luzon Volcanic Arc
- East - Philippine Arc
- Negros - Panay Arc
- Sulu - Zamboanga Arc
- Cotabato Arc
Sedimentary Basin that are PMB Affinity
- Ilocos - Central Luzon Basin
- Cagayan Valley Basin
- Southern Luzon - Bicol Basin
- Mindoro Basin
- Iloilo Basin
- Visayan Sea Basin
- Samar Basin
- Agusan - Davao Basin
- Cotabato Basin
Sedimentary thickness of Ilocos Central Luzon Basin
8000m / 8 km
Sedimentary thickness of Cagayan Valley Basin
8,100m / 8.1 km
Sedimentary thickness of Southern Luzon - Bicol Basin
4,600 m / 4.6 km
Sedimentary thickness of Iloilo Basin
5,000m / 5km
Sedimentary thickness of Visayan Sea Basin
4,000 / 4 km
Sedimentary thickness of Agusan - Davao Basin
12,000 m / 12km
Sedimentary thickness of Cotabato Basin
8,000 m / 8km