Theories On The Origin of The Philippines

Davao del Norte State College Panabo City, Philippines GRADUATE SCHOOL DEPARTMENT Advanced Systematics THEORIES ON THE ORIGIN OF THE PHILIPPINES There are theories that support the origin of the Philippines: 1. Continental Drift Theory  it supports the claim of Alfred Wegener (1912) that two (2) continents drifted some 200 million years ago: Laurasia to the northern hemisphere and Gondwanaland to the southern hemisphere  the Philippines is believed to have been part of the continent Laurasia  according to Alfred Holmes (1944), the two continents drifted as a result of pressure caused by volcanic eruptions in the ridges and in the center of the Pacific Ocean and Atlantic Ocean  The Philippines sits on a sub-plate of the Eurasian Plate now called Philippine Plate  Based on this theory, scientists believe that the Philippine archipelago was part of the Asian continent and was only separated due to geological changes.

2. Pacific Theory  it supports the claim of Dr. Bailey Willis that the Philippines was formed due to eruptions of volcanoes in the periphery of the Pacific Basin of the Pacific Ocean as far as the eastern part of Asia continent  such eruption of underwater volcanoes is called volcanism

 the eruptions of underwater volcanoes some 200 million years ago resulted in the piling up of extrusive or molten rocks causing the emergence of islands in the Pacific Ocean  the continuing process of volcanism formed the structural foundation of the Philippines  Pacific theory contends that a study of the nature of the rocks beneath the ocean and the volcanic character of the archipelago made Dr. Bailey Willis conclude that the Philippines was formed through the marginal and peripheral eruptions of the Pacific Basin. The eruptions of the submarine volcanoes during the remote geologic past and the piling up of their extrusives caused the emergence of the islands above the sea, giving rise to the Philippine Archipelago (Salita, 1997).  To prove their theory, scientists cited some evidences such as the elevation of Baguio City and other nearby mountain areas where corals and old volcanic stocks (rocks formed under great heat and pressure deep beneath the earth’s surface) are found. 3. Land Bridges Theory  the formation of glacier in many parts of the world resulted in ice sheets to cover a great portion of North America, Europe and Asia  according to this theory, all the islands in the Philippines were connected to each other and that others were even connected to nearby countries in Southeast Asia by land bridges  They theorize that during the Ice Age or Pleistocene, about 250,000 years ago, the water surrounding the Philippines receded to about 156 feet below its present level  When the Earth got warmer and the icecaps began to melt, the water covered and submerged the land bridges.  when the ice melted, the land bridges went underwater, separating the islands from each other and cutting the Philippines from the rest of Asia  Scientists cite the similarity of the plants and animals in the Philippines to those of its neighbors in Asia as evidences that prove their theory.  These land bridges were between Borneo and Palawan; Borneo, Sulu and Mindanao; New Guinea and Mindanao; and between Taiwan and Batanes  As you can see in the map Batanes group of island looks like connected to Taiwan this where part of Land Bridges before.

4. Asiatic Theory  according to this theory, the Philippines was not part of the continental shelf of Asia  it claims that two (2) processes of diastrophism namely, upfolding and upthrust faulting caused the rising (or emergence) and formation of the Philippine archipelago, and all mountains in the archipelago  this occurred during the Paleozoic Era some 200 million years ago  Asiatic holds view that the Philippines was once a part of the continental shelf of Asia. Dr. Leopoldo Faustino (1928) stated that: The present land areas of the Philippines are merely the higher portions of a partly submerged mountain mass…The outline of the Archipelago was first marked at the close of the Paleozoic Era during the Permian Revolution when a movement of the Asiatic land mass to the south caused the China Sea depression and crumpled the edge of the continental platform. In other words the Philippine Islands formed the barrier that separated the waters of the Pacific Ocean from the waters of the present China Sea.  The present landforms of the Philippines have come about through the complex process of diastrophism, vulcanism and gradation. These landforms are very much interrelated with the origin of the Archipelago itself. The occurrence of tectonic earthquake is an effect of diastrophism. The formation of elongated mountains such as the Sierra Madre and the Cordillera is caused by diastrophism while the conical peaks are the result of vulcanism. Mt. Apo, Mayon Volcano and Kanlaon Volcano are examples of volcanic mountains. The erosion of the highlands and the consequent deposition of the sediments at the oceanic basin comprise the process of gradation. It is gradation that generally causes the formation of minor landforms, such as rivers, valley, lakes, deltas, hills, rapids, and falls. The deltas formed by Pasig River and Pampanga River as they enter Manila Bay are the results of gradation process (Salita, 1997).  The location of Philippines on the western margin of the Pacific Ocean, which is comparatively unstable segment of the earth’s crust may help explain the pattern of landform

development. The entire margin of the Pacific Basin from Japan to Taiwan, Philippines, Indonesia, and New Zealand owes much of its development to the action of the forces of folding, faulting, and volcanic activity. Geologists call this region as the “girdle of fire” or “ring of fire” because it is a region of frequent volcanic activity (Salita, 1997).  The geologic processes aforementioned resulted to the Philippines as an inverted Yshaped archipelago consisting of more than 7,000 islands and islets. These islands are commonly grouped into three major divisions namely: Luzon; Visayas; and Mindanao. Its land surface is crisscrossed by mountains and drained by small river systems.

Submitted by:

ROMEL S. VILLARUBIA MST- Biology Student