Ilocos-Central Luzon Basin

Ilocos-Central Luzon Basin is a sedimentary basin and stratigraphic formation in the Ilocos Region and Central Luzon Region, Philippines.^[1] It is one of the 16 major sedimentary basins in the country and stretches from the vicinity of the Manila metropolitan area in the south to Ilocos Norte in the north.^[2]

The basin is filled with sedimentary rocks that range in age from Late Oligocene to Pliocene.^[3] These rocks were deposited in a variety of environments, including deep marine, shallow marine, and non-marine settings. The basin is also home to a number of hydrocarbon reservoirs, which are currently being explored for oil and gas potential.

Stratigraphic groupings

Ilocos

Suyo Schist - greenschist, serpentinite, chert

Ilocos Peridotite - serpentinized peridotite
Bangui Formation - sandstone, conglomerate, mudstone; includes olistostrome
Magabobbo Limestone - micritic limestone, calcarenites, minor argillites
Bojeador Formation - conglomerate, graywacke, shale, limestone and associated volcanic flows and pyroclastics
Pasaleng Quartz Diorite
Dagot Limestone - reefal limestone, calcarenites, biosparites, minor calcareous volcanic conglomerate, particularly at the base and middle section
Batac Formation - thinly bedded sandstone and shale; conglomerate
Pasuquin Limestone - limestone with minor calcareous conglomerate, calcirudite, calcarenite
Uplifted Coral Reefs

Luzon Central Valley

West side

Aksitero Formation - Lower Bigbiga Limestone – micritic limestone with tuffaceous turbidites and minor chert; Upper Burgos Member – Limestone, tuffaceous sandstone, siltstone and mudstone. This is coequival with Bigbiga Limestone.
Moriones Formation - interbedded sandstone, shale, conglomerate with minor limestone; identified members are Sansotero Limestone and Malo Pungatan Limestone
Malinta Formation - Lower Pau Sandstone – sandstones with minor tuffaceous shale, conglomerates and lapilli tuff; Upper Aparri Gorge Sandstone – sandstones with shale stringers and conglomerate lenses
Tarlac Formation - interbedded sandstone, shale, conglomerate
Amlang Formation - turbiditic sandstones and shale with minor conglomerates
Cataguintingan Formation - mainly tuffaceous sandstones, with interbeds of siltstones, shales and conglomerate and minor limestone lenses
Bamban Formation - tuffaceous sandstone and lapilli tuff with basal conglomerate.
Damortis Formation - sandstone, calcarenite, siltstone, limestone and marl

East side

Barenas-Baito Formation
Bayabas Formation
Angat Formation
Madlum Formation
Makapilapil Formation
Lambak Formation
Tartaro Formation
Guadalupe Formation

References

[1] Lexicon of Philippine Stratigraphy, Rolando Peña, 2008

[2] ttps://www.researchgate.net/figure/Ophiolites-and-ophiolitic-rocks-found-in-different-parts-of-the-Philippine-archipelago_fig2_226705935#:~:text=2013).,Discussion%20Faunal%20remarks.%20...

[3] ttps://www.researchgate.net/figure/A-Map-of-the-Luzon-Island-showing-major-structures-and-the-location-of-the_fig1_322976452#:~:text=The%20basin%20is%20one%20of,%2C%201978).%20...&text=...,-lithologic%20homogeneity%20rather

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