Palawan Island (page 235)
Divided into North Palawan block and Central and South block
o Boundary along Sabang Thrust (UNDP, 1985) (MMAJ-JICA, 1988)
o Disparity is due to obliqueness of tilting during the collision of NPB and PMB
Northern Palawan
Paleozoic and Mesozoic strata (Malampaya Sound Group) are olistolith
Malampaya Sound Group (Bacuit, Minilog, Liminangcong, Guinlo)
Bacuit (dating El Nido) Formation
o Middle Permian to Late Permian
o Unconformable over Barton Metamorphics, underlies Minilog Limestone
o Brecciated sandstone, limestone, chert, altered tuff, calcareous sandstone and
contorted alternation of sandstone and slate
o Basal part of Malampaya Sound Group
Minilog Limestone
o Late Permian to Middle Triassic
o Conformable over Bacuit Formation
o Limestone
o Possible extension in Carabao Island, Romblon
Liminangcong Formation
o Late Permian to Late Jurassic
o Unconformable over Minilog Limestone, underlies Coron Limestone
o Chert/radiolarite, black slate, tuff
o Probable extensions in Tagauayan, Quinluban, Concepcion and Silad Islands in Sulu Sea
Coron Formation
o Late Triassic to Late Jurassic
o Unconformable over Liminangcong Formation
o Dominantly limestone; subordinate shale and sandstone
o Equivalent to King Ranch Formation and Malajon Formation
Guinlo Formation
o Late Jurassic to Early Cretaceous (no fossils, based on stratigraphic position)
o Unconformable over Coron Formation, underlies Maytiguid Limestone
o Sandstone, conglomerate
o Weakly metamorphosed massive coarse-grained sandstone (quartzite)
Paly Serpentinite
o Cretaceous
o Found in Paly Island and in some tributaries in Roxas
o Serpentinized peridotite and serpentinite
o Equivalent to the Rizal Serpentinites
Barton Group
Caramay Schist
o Cretaceous
o Underlies Concepcion Phyllite
o Muscovite schist, graphite schist, quartzite
o Former sedimentary rocks formed Carboniferous – Early Permian
Concepcion Phyllite
o Cretaceous
o Between Caramay Schist and Babuyan Formation
o Phyllite, semischist, slate, quartzite
o Babuyan River Turbidites facies with lower degree of metamorphism than Caramay
Boayan Formation
o Late Cretaceous
o Overlies Concepcion Phyllite, underlies Maytiguid Limestone
o Sandstone, mudstone
o Unmetamorphosed part
Maytiguid Limestone
o Eocene
o Unconformable over Liminangcong Formation
o Limestone
o Correlative to Bailan Limestone (Tablas) and Sumbiling Limestone (Bataraza)
St. Paul Limestone
o Late Oligocene – Early Miocene
o Unconformable over Palawan Ophiolite and the Maytiguid Limestone
o Limestone
o Coeval (same age) to Reed Bank Limestone and Ransang Limestone
Kapoas Granite
o Middle Miocene
o Intrudes the Liminangcong Formation and Barton Group
o Granite, quartz monzonite, granodiorite, quartz diorite
o Melting is due to underplating of the continental crust beneath North Palawan
(paexlain?)
Piedras Andesite
o Middle Miocene (?)
o Intrudes the surrounding ultramafic rocks
o Andesite
o Dense hornblende andesite with some quartz
Manguao Basalt
o Pliocene – Pleistocene
o Distributed around Lake Manguao, Taytay; Cuyo Island Group
o Basalt, subordinate shale, siltstone, conglomerate and pyroclastic rocks
o Equivalent to the basaltic flows in Cuyo Group of Islands
Central and Southern Palawan and Balabac Island (page 251)
Palawan Ophiolite
Beaufort Ultramafic Complex
o Cretaceous
o Underlies gabbro
o Harzburgite, dunite, pyroxenite, peridotite
o Correlative to the Paly Serpentinite
Stavely Gabbro
o Cretaceous formation, Middle Eocene emplacement
o Overlies Beaufort Ultramafic Complex, thrusted over Espina Formation
o Gabbro
o Cumulate dunite < troctolite layer < isotropic gabbro < layered gabbro
Espina Formation
o Late Cretaceous
o Unconformably underlies Panas Formation and Sumbiling Limestone
o Spilitic basalt with intercalated sandstone and chert
o Pelagic clastic rocks constitute the sedimentary carapace of Palawan Ophiolite
Dalrympole Amphibolite
o Middle Eocene
o Metamorphic sole of the Palawan Ophiolite
o Amphibolite, greenschist
o Partly equivalent to Inagauan Metamorphics and Kabangan Metamorphics
Panas Formation
o Eocene
o Unconformable over Espina Formation, partly intertongues with Sumbiling Limestone
o Sandstone, siltstone, shale, conglomerate
o Highly indurated, interbedded, sparsely fossiliferous
Sumbiling Limestone
o Eocene
o Unconformable over Espina Formation, intertongues with Panas Formation
o Massive, partly crystalline, dark gray limestone
o Equivalent to Maytiguid Limestone
Pandian Formation
o Middle Eocene – Early Oligocene
o Unconformable over Panas Formation
o Massive sandstone, shale, conglomerate
o Equivalent to Pulute Formation
Sagasa Melange
o Possible Oligocene
o Probably formed through tectonism
o Chaotic mixture of turbidite, pillow basalt, chert, quartzite
o Outcropping in the Ulugan Bay area
Balabac Formation
o Late Oligocene – Miocene
o Unconformable over Espina Formation
o 4 members:
North Bay Member: limestone with interbeds of thin sandstone and shale
Tagkalasa Member: sandstone with thin layers of shale
Catagupan Member: shale and sandstone with minor limestone beds
Sigumay Member: arkosic sandstone
Ransang Limestone
o Early Miocene
o Conformable over Pandian Formation, conformably underlies Isugod Formation
o Limestone, calcarenite and calcisiltite
o Relatively shallow marine environment
Isugod Formation
o Middle Miocene
o Unconformable over Espina Formation, underlies Alfonso XIII Formation
o Shale and sandstone; minor limestone; conglomerate
o Partly correlative to the Tumarbong and Quezon Formations
Alfonso XIII Formation
o Late Miocene
o Unconformable over Isugod Formation
o Limestone with occasional calcareous shale and sandstone interbeds
o Equivalent to Tabon Formation
Iwahig Formation
o Pliocene
o 2 members:
Pusok Conglomerate Member
Panoyan Limestone Member
Tagburos Opalite
o Probably deposited by hot springs during Pleistocene
o Irregular masses of yellowish to mocha brown siliceous rocks
o Opalite; chalcedony and variegated opaline silica
