320 likes | 778 Vues
Andes and Himalayas. Fold Mountains. Eastern parts of the Pacific Ocean Mountains mainly formed on the edges of the continents Andes Mountain Himalayan Mountains. Andes. Located along the western coast of South America Is the longest continental mountain range
E N D
Fold Mountains • Eastern parts of the Pacific Ocean • Mountains mainly formed on the edges of the continents • Andes Mountain • Himalayan Mountains
Andes • Located along the western coast of South America • Is the longest continental mountain range in the world at about 7 000km in length and 200 to 700km wide. • Average height of 4,000 m • Peak height of 6 962m above sea level at Mt. Aconcagua
Formation • Mainly caused by the compression of the western rim of the South American Plate due to the subduction of the Nazca Plate. • Oceanic – Continental Plates • Convergent Plate Boundary
Landforms • Fold Mountains – Caused by the subduction of the Nazca plate, resulting in the contortion of sediments which fold together to form the Andes itself • Trenches – Peru-Chile trench
Landforms • Volcanoes – Result of subduction of the Nazca and Antarctic Plate underneath the South American Plate, causing the former to melt partially and rise through fractures in the lithosphere as magma.
Himalayas • Located in Nepal, Asia • Separates the Indian subcontinent from the Tibetan Plateau.
Himalayas • Home to the world’s highest peaks, sometimes known collectively as the Eight-thousanders due to their height. • Includes mountains such as Mount Everest and K2 • Imagine Mt Aconcagua in Andes, but a hundred of them in a range of mountains, with some even higher!
Formation • Formed by the continental collision at the convergent boundary of the Indo-Australian Plate and the Eurasian Plate, creating a fold mountain.
Formation • Youngest mountain on the planet • Consists mostly of uplifted sedimentary rock and metamorphic rock
Formation • India, moving at 15 cm per year, collided with the Eurasian Plate about 10 million years ago
Formation • This indirectly proved the existence of the Tethys Ocean • Sedimentary rocks which had settled on the ocean floor were light enough to be crumpled into mountain ranges instead of sinking with the oceanic part of the Indo-Australian Plate.
Formation • The Indo-Australian Plate is sill moving at about 67 mm per year! • This in turn causes the Himalayas to rise at about 5 mm per year • This may not seem much, but it still means that the Himalayas is geologically active. • The movement makes the region seismically active leading to the occasional earthquake.
What is Folding? • Folding refers to a bending in rock strata caused by compression. • This powerful force of compression pushes the rock layers towards each other; thereby creating folds and contortion.
Weak compressional force Strong compressional force Types of folds:
Types of folds • Same compressional force applied on both sides: simple/symmetrical folds with limbs of the same steepness.
Types of folds • A larger compressional force is applied on one side: asymmetrical fold with uneven limbs (one steeper than the other)
Types of folds • The compressional force being so great on only one side: overfold/overturned fold with both limbs sloping in the same direction
Types of folds • When one limb of the overfold/overturned fold has been pushed over the other limb until the axis of the fold is almost horizontal: Recumbent fold • Exceptionally powerful compressional force applied on one side can cause a recumbent fold to fracture: Overthrust fold is formed, since the upper part of the recumbent fold thrusts forward along the plane of fracture.
Reflections • Not only has this project taught me the usual academic things such as folding and the formation of fold mountains, it has also helped me in the aspects of teamwork and time management through the creation of a presentation • Grady
Reflection • This presentation has helped me learn alot about folding and the formation of the Himalayas and Andes, and also improved my presentation skills and organisation. • Ming Shi
Reflection • I have learnt many things about fold mountains and the types of folds and how the Himalayas and Andes were formed. I also learnt more about working as a team and co-operating with each other • Wesley
Reflection • This project has taught me how to manage my time properly and also the idea of team spirit, by co-operating with each other to complete tasks. I have also learnt a lot about how mountains are forms by folding and the different kinds of folds that can occur. • Zamen
Bibliography • Aspects of Physical Geography • http://www.wikipedia.org/Andes • http://www.wikipedia.org/Himalayas • http://en.wikipedia.org/wiki/Fold_(geology) • R.B Bunnet, “Interactive Geography 3” • http://en.wikipedia.org/wiki/Pangaea
Thank you! • Are there any questions?