Geologists from the Mines and Geosciences Bureau (MGB) MIMAROPA Region conducted geological mapping of Baldat and Culion Quadrangles in Palawan, March 28 to April 12, to identify and map the distribution of the different lithologic units covering these areas.

The Baldat Quadrangle covers Brgy. Maglalambay of Busuanga and Barangays Galoc, Luac, Malaking Patag, and Baldat of Culion municipality. Meanwhile, covered in the Culion Quadrangle are the Poblacion Barangays Jardin, Culango, Balala, Libis, Tiza, and Osmeña of Culion; and Barangays Bintuan, Lajala, Tagumpay, Banuang Daan, and Cabugao of Coron.

A total of three formational units were mapped across the two quardangles: Liminangcong Formation, Guinlo Formation, and Coron Formation.

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MGB MIMAROPA geologist measures the strike and dip readings of the bedded chert outcropping at Sitio Malpok, Brgy. Lajala, Coron

Massive and bedded chert exposures were extensively mapped along Barangays Galoc, Luac, Malaking Patag, and the poblacion barangays of mainland Culion, most of the islands to the north and east, as well as Barangays Bintuan and Lajala of Coron municipality. The bedded chert is thinly to medium-bedded, varied in color from red to gray to black, and complexly folded in some exposures.

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MGB MIMAROPA geologist samples the clast of the brecciated rock exposure at Sitio Kabol-kabol, Brgy. Malaking Patag, Culion

Breccia exposures interpreted to belong to Guinlo Formation were observed stretching from Chindonan Island of Brgy. Libis passing through Brgy. Baldat towards the western portions of Barangays Malaking Patag and Binudac. The breccia exposures contain mostly boulder-sized clasts of chert and clastic rocks set in a generally unconsolidated matrix of clay and sand.

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MGB MIMAROPA geologist measures the trend of the folded alternating gray and red chert beds outcropping at Marily Island, Brgy. Baldat, Culion

The limestones of Coron Formation were concentrated in Sangat Island of Brgy. Binudac and in Coron Island, comprising the karstic terrain of Barangays Banuang Daan and Cabugao. These limestones are highly indurated, generally buff to gray in color, and pinnacle karst-forming. Some samples contain ooids, while others are recrystallized implying slight marbleization.

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The team conducted an exit conference attended by personnel from different offices of Culion LGU to discuss the preliminary results of the mapping activity

At the end of the field mapping, the team coordinated with the LGU of Culion to host an exit conference presenting the data gathered throughout the fieldwork duration. During the said meeting, the team discussed the objectives, methodology, preliminary results, and importance of the geologic mapping activity before the personnel from the Municipal Disaster Risk Reduction and Management Office, Municipal Planning and Development Office, Engineering Office, Office of the Municipal Administrator, Office of the Municipal Assessor, and Tourism Office.

The quadrangles of Baldat and Culion are part of the annual targets for geologic mapping of the MGB MIMAROPA Regional Office under the Bureau’s National Geological Quadrangle Mapping Program (NGQMP).

The NGQMP aims to undertake a systematic geologic mapping of the entire country on a 1:50,000 scale utilizing Interferometric Synthetic Aperture Radar topographic maps as base maps and Geographic Information System technology for data processing and map generation. The geologic mapping activity incorporates reviews of previous geologic literature in conjunction with field surveys and validation to output geologic maps and technical reports that provide useful information to stakeholders for the development of the country’s mineral, energy and water resources; and for environmental protection, land use classification, planning and development.

The remaining official geologic mapping target of MGB MIMAROPA for CY 2022 is the Halsey Harbor Quadrangle, which covers the southwestern portion of Culion municipality, particularly Barangays Binudac, Malaking Patag, Halsey, and Carabao. The MGB MIMAROPA Region also seeks to conduct the mapping activity in the second quarter of 2022.