The Land Builds Up Atoc Bonggot Lara Sanguenza Valiente The Land Builds Up Mountain Formation Continental Drift Theory Sea-floor Spreading Plate Tectonics (Plate Tectonics and the Philippines) Mountains in the Philippines Mountain Formation What is a Mountain? • A mountain is a landform that rises high above the surrounding terrain in a limited area. What do Mountains look like? • Mountains usually have steep, sloping sides and sharp or slightly rounded ridges and peaks. • Mountains can be rocky and barren. What do Mountains look like? How are mountains formed? • Mountains are formed by • Mountains usually have slow but gigantic steep, sloping sides and movements of the earth's sharp or slightly rounded crust ridges and peaks. • Mountains can be rocky and barren. What different types of Mountains are there? 1. Fold mountains Himalayan Mountains in Asia the Andes in South America the Rockies in North America 2. FAULT-BLOCK MOUNTAIN the Sierra Nevada mountains in North America 3. Dome Mountains 4. Volcanic Mountains Mt. Pinatubo in the Philippines Continental Drift Theory Continental Drift Theory the movement of the Earth's continents relative to each other by appearing to drift across the ocean bed Sir Francis Bacon Made first map of the Atlantic Ocean (1620) Noticed parallelism of opposite shores Alfred Wegener A german geologist and meteorologist who first proposed the continental drift The Origin of Oceans and Continents He hypothesized that there was a gigantic supercontinent 200 million years ago, which he named Pangaea, meaning "All-earth" Pangaea started to break up into two smaller supercontinents, called Laurasia and Gondwanaland Terms to remember: Panthalassa - large ocean surrounding supercontinent Laurasia - Europe and North America joined together Gondwanaland - Southern hemisphere portion of supercontinent Wegener's Evidences *Rock Types and Structures* Match - Africa and South America Wegener matched at shorelines, later Bullard gets better match at edge of continental shelf *Paleoclimatic evidence* Gondwanaland glaciations Sea-floor Spreading Sea-floor Spreading The process in which the ocean floor is extended when two plates move apart As Magma rises through the cracks and seeps out onto the ocean floor, the plates move apart thus spreading the sea-floor • When magma piles up along the crack, a long chain of mountains forms gradually on the ocean floor Ie. mid-Atlantic ridge; pillow basalt Mid-ocean Ridge - a place where two of the Earth's tectonic plates are slowly moving apart from each other The mid-ocean ridge system circles the entire Earth, somewhat like the seams of a baseball The boundaries where the plates move apart are constructive new crust is being formed and added to the ocean floor The ocean floor gradually extends and thus the size of these plates increases Subduction – the process in which smaller plates melts back to the earth Subduction Deep ocean Trenches Trenches deep under water that form where the oceanic crust bends downwards Marianas Trench Major characteristics of the seafloor: • the age of the seafloor is progressively older away from mid-ocean ridges; • older parts of the seafloor have the greatest potential to have accumulated sediments over the longest time Evidences of sea-floor spreading Presence of pillow shaped rocks Drilling into the sea floor The closer you get to the mid-ocean ridge, the younger the rocks. The farther you get, the older the rocks. Plate Tectonics Plate Tectonics is a scientific theory that describes the largescale motions of Earth's lithosphere Main features: • The Earth's surface is made up of a series of large plates; • These plates are in constant motion travelling at a few centimetres per year; • The ocean floors are continually moving, spreading from the centre and sinking at the edges; • Convection currents beneath the plates move the plates in different directions; • The source of heat driving the convection currents is radioactive decay; The movement of the plates creates three types of tectonic boundaries: Convergent - where plates move into one another; Divergent - where plates move apart; Transform - where plates move sideways in relation to each other Convergent Boundaries plates serving landmasses collide, the crust crumples and buckles into mountain ranges convergent boundaries also occur where a plate of ocean dives, in a process called subduction Divergent Boundaries magma from deep in the Earth's mantle rises toward the surface and pushes apart two or more plates. Mountains and volcanoes rise along the seam. Transform Boundaries two plates grind past each other along what are called strike-slip faults. These boundaries don't produce spectacular features like mountains or oceans, but the halting motion often triggers large earthquakes Age of the Sea Floor *This figure displays the estimated age of sea floor crustal plates with red the youngest and blue the oldest Mountains in the Philippines Mt. Apo location : island of Mindanao Mt. Pulag location : Luzon Mt. Kitanglad location: Bukidnon Mount Mayon location: Albay Mt. Dulang location: Lantapan, Bukidnon Thank you for listening…