The Mines and Geoscience Bureau Regional Office IX (MGB, R-IX) conducted systematic geological mapping in Lakewood Quadrangle (Sheet No. 3646-IV) in Zamboanga Peninsula last May 23 to June 20, 2019 as part of the 2019 Quadrangle Geological Mapping Project. The purpose of the mapping program is to produce and update the 1:50,000 scale quadrangle maps in Region IX, which is one of the least mapped area in the Mindanao. Four quadrangles are targeted for the year 2019 with no published maps, all of which are within Zamboanga Peninsula. It is located in the north central portion of Zamboanga Peninsula, south of Sindangan River Quadrangle. It covers sections of the Municipality of Kumalarang and Pagadian city; and a large portion of the Municipalities of Bayog, Lakewood and Tigbao. The Geological Quadrangle Mapping Team is composed of Lawrence Zamoras, Ph. D., as the team leader and two other geologists Kris Elvis Alferez and Glen Ford Gamelo.
Field activities consisted of examination of rock exposures along accessible tracks and in coastal areas, physical and megascopic description of outcrops and rock samples, sampling of representative rock units and favorable units that contain fossils, structural feature measurements of prevalent deformation and sedimentary structures, and photograph documentation. The mapping utilized 1:50,000 topographic base map of NAMRIA furnished through their website. The locations were obtained using the Global Positioning System (Garmin GPSMAP 64s), while the data gathered were plotted on a 1:10,000 topographic map generated from the Interferometric Synthetic Aperture Radar (IFSAR) 2015 of NAMRIA.
This report presents the information gathered during the implementation of the Quadrangle mapping in Central Zamboanga Peninsula and describes the rock units within the study area. It is also intended to supplement the quadrangle map as the final output of the program which is a technical report and GIS-based geologic maps that are expected to be extremely useful for many practical applications such as in mineral exploration, groundwater resource and vulnerability assessment, geohazard mapping, solid waste disposal site selection, land use planning, and other applications.
Lakewood Quadrangle covers the latitude N 7° 50’ 0” to 8° 0’ 0”, and longitude E 123° 0’ 0” to 123° 15’ 0” is approximately centered in the Municipality of Lakewood. From Zamboanga International Airport, the target municipalities covered by Lakewood Quadrangle are easily accessible via all-weathered national road which serves as the main access throughout the entire peninsula. Far-flung areas can be accessed using a motorbike (locally known as habal-habal).