Northern Samar: Geologists from the National Committee on Geological Sciences (NCGS) have confirmed the presence of unique rock formations in Northern Samar, dating back approximately 15 to 20 million years ago. These findings solidify the province's geological significance on both national and international scales, the Northern Samar provincial government said in a statement.
According to Philippines News Agency, the study highlights the iconic rock islets of Biri, which may have originated from ancient volcanic rocks in Lavezares and Allen towns. "These volcanic formations, known as Allen Phonolite, date back approximately 20 million years and were uplifted above sea level through tectonic processes," the provincial government stated, citing results of the three-day assessment that concluded on Thursday.
The provincial government said field investigations also unfold several remnants of volcanic eruptions across the Lavezares-Allen-Biri area, with preserved lava flow structures indicating significant volcanic activity around 15 million years ago. "In addition, geological surveys on Biri Island have uncovered rare analcime-bearing sandstones and conglomerate findings that enhance the site's international scientific value and bolster its potential designation as a UNESCO Global Geopark," it said.
On March 23, 2025, the provincial government welcomed a three-day comprehensive assessment of geological wonders in the province, eyed to strengthen the province's status as a site of national scientific and geologic importance. The team is composed of geologists from the NCGS, Mines and Geosciences Bureau central office, and the University of the Philippines-National Institute of Geological Sciences.
The assessment will advance the campaign for the declaration of Biri Rocks and other geological wonders in the province of Northern Samar as National Geological Monuments. Last year, Northern Samar formalized its application to declare the Biri Rock Formation as a United Nations Educational, Scientific and Cultural Organization (UNESCO) Global Geopark. A team visited the site for an initial assessment.
