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Regardless of who wins the legal battle, the Masungi Limestone as a geological formation must be protected
The recent decision of the Philippine government, through its Department of Environment and Natural Resources (DENR), to rescind its contract with the developer of the Masungi Georeserve in Tanay, Rizal, could put an important geological effort of confirming the inland presence of Paleocene rocks in the Philippines in jeopardy.
Whichever party emerges victorious in this legal battle, the Masungi Limestone as a geological formation must be protected by way of a robust conservation and preservation program.
Conservation is an anthropocentric approach to protect the natural environment that promotes responsible and sustainable use of its natural resources. It allows a certain extent of development to support human existence, such as use of its raw materials and repurposing of areas properly identified as fit for development, provided impacts are minimized. On the other hand, preservation is premised on an ecocentric approach that puts premium on the intrinsic value of nature and all life, regardless of human benefits.
Forest conservation and environmental protection
Forest conservation requires a good understanding of the nature of rocks upon which the trees grow for biodiversity to flourish. In general, vegetation is lush — thus the rich biodiversity — in limestone areas, like in the Masungi Georeserve and environs, thanks to the porous nature of the rocks at the root level. But deep underneath the rocks, way beyond the roots can reach — like in other karst terrains where rocks dissolve in water over time by virtue of their composition — are networks of caverns and hollows that convey water underneath. This explains why there are no big rivers at the surface of karst terrain. If rivers exist in areas underlain by limestone like in Masungi, they normally run underground — think St. Paul Underground River in Palawan. Watersheds underlain by limestones are quite complex — some, by nature, do not hold large amounts of water flowing at the surface.
The small streams and waterfalls that run and stand within the area intended to be developed into a housing village for government employees inside the Masungi Georeserve flow over rock formations that do not belong to the Masungi Limestone — the geological formational name assigned to the limestone rocks in Masungi and nearby areas. The rocks exposed on the stream bed and at the water falls are part of a geological formation which is older than the Masungi Limestone, known as the Kinabuan Formation, composed of indurated, impermeable volcaniclastic rocks of Cretaceous age (125 to 66 million years old). Although exposed in the georeserve to a limited extent, the Kinabuan Formation that contains the impermeable rocks allows small streams to flow.
Even before the Masungi Georeserve became open for geotourism, a geological team from the Mines and Geosciences Bureau (MGB) of the DENR had already been involved as early as the late 1990s in efforts aimed towards its conservation, mainly by conducting a geohazard assessment of the housing village and the limestone formations around it. Results of the geohazard assessment were taken into consideration by the developer to conserve the site. Landslide-prone areas were identified, allowing certain sections that were originally allotted for residential lots, to be repurposed into non-residential areas where non-permanent structures would be constructed, such as rock gardens, parks, and view decks, in consideration of their proneness to landslides/rockslides.
Masungi Limestone as a geological formation in Philippine geology
The Masungi Limestone as a geological formation needs to be preserved as well, not only because of its vital ecological role as host to biodiversity but also because it holds the key to unlocking a standing problem in Philippine geology that remains unresolved to this day — the missing deposits of the Paleocene on land.
Available information suggests that in the Philippines, the existence of geological deposits of the Paleocene epoch (between 65 and 56 million years ago) remains to be confirmed on land (the Paleocene has been encountered in an offshore well in the Recto Bank in northwest Palawan). Such absence of representative rock layers forms unconformities, which suggest several geological scenarios in the past, among them is extensive erosion or non-deposition that may have been caused by extreme chaotic tectonic events, such as extensive earthquakes and volcanic eruptions, like those that are sometimes postulated to be the culprits of the extinction of the dinosaurs 66 million years ago. The Paleocene is the record of life and earth processes immediately after the death of the dinosaurs.
Recently, a team of paleontologists from the National Institute of Geological Sciences of the University of the Philippines (UP NIGS) discovered in limestone exposures outside of the Masungi Georeserve fossils suspected to be of probable Paleocene age. But this still needs to be confirmed, and the limestone exposures within and around the georeserve might provide the samples to confirm this age. If Masungi is not preserved, the chances of confirming an inland Paleocene age in the Philippines are diminished.
In March of 2022, senior geology students of UP NIGS conducting fieldwork in the georeserve discovered for the first time a rock layer containing abundant nummulites, fossils believed to have proliferated in the Eocene (56 to 34 million years ago), the epoch that immediately succeeded the Paleocene. This is a step forward in the search for the missing Paleocene in the Philippines. Perhaps the rock layers immediately below will reveal horizons that contain preserved Paleocene fossils.
The Masungi Limestone extends beyond the confines of the Masungi Georeserve. To protect it as a geological formation, some sections of it should be preserved, while others must be conserved. To achieve this, a comprehensive conservation and preservation plan should be laid down and implemented. – Rappler.com
Mario A. Aurelio, PhD is a professor of geology at the National Institute of Geological Sciences of the University of the Philippines, and head faculty of the Structural Geology and Tectonics Laboratory of UP NIGS. He is co-editor and co-author of a book entitled “Geology of the Philippines, 2nd Edition” published by MGB-DENR. He teaches a subject for senior geology students of UP NIGS entitled “Geology and Tectonics of the Philippines and Southeast Asia.“
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