The key answer of exercise 3
The key to exercise solutions in chapter Oral presentation 2 for the textbook Step Up Gold Exam Trainer with authors Philippa Bowen e Denis Delaney from Oxford University Press
Question
Prepara una presentazione orale sulle placche tettoniche. Prima copia lo spidergram e scrivi appunti per ogni sezione.
Answer
Title: Unveiling the Dynamic World Beneath Our Feet: Exploring Tectonic Plates
Introduction
Tectonic plates are more than just geological elements; they are the architects of our planet's landscapes, shaping continents and oceans over millions of years. Today, we embark on a journey deep into the Earth's crust to uncover the mysteries of tectonic plates.
What are Tectonic Plates?
Tectonic plates are massive, rigid pieces of the Earth's lithosphere, ranging from about 50 to 250 kilometers in thickness. Composed of the crust and the uppermost part of the mantle, these plates float on the semi-fluid asthenosphere beneath them. The Earth's lithosphere is divided into several major and minor tectonic plates, each constantly in motion due to the convective currents within the mantle.
Structure of the Earth
The Earth's interior consists of several layers: the inner core, outer core, mantle, and crust. The crust, where we reside, is the thinnest and outermost layer, divided into oceanic and continental crust. Beneath the crust lies the mantle, a semi-fluid layer where convection currents drive the movement of tectonic plates.
Movement of Continents
Continental drift, proposed by Alfred Wegener in the early 20th century, suggests that continents were once connected in a supercontinent called Pangaea. Over millions of years, the continents have drifted apart due to the movement of tectonic plates. This movement is driven by the process of plate tectonics, which includes subduction, seafloor spreading, and continental collisions.
New Zealand - A Tectonic Wonderland
New Zealand is located at the boundary of the Pacific and Indo-Australian plates, making it a hotspot for tectonic activity. The country experiences frequent earthquakes, volcanic eruptions, and geothermal phenomena due to plate interactions. The diverse landscapes of New Zealand, from rugged mountains to geothermal valleys, are a testament to its dynamic geological history.
What Happens Where Tectonic Plates Meet?
At plate boundaries, various geological phenomena occur, shaping the Earth's surface. Divergent boundaries witness seafloor spreading and the formation of mid-ocean ridges. Convergent boundaries lead to subduction zones, volcanic arcs, and mountain ranges. Transform boundaries result in earthquakes as plates slide past each other horizontally.
The Ring of Fire
The Pacific Ring of Fire is a horseshoe-shaped zone encircling the Pacific Ocean, known for its intense tectonic activity. Approximately 75% of the world's active and dormant volcanoes lie within the Ring of Fire. This region is also prone to powerful earthquakes and tsunamis, making it a focal point for scientific study and natural hazard mitigation efforts.
Conclusion
Tectonic plates are the driving force behind the dynamic nature of our planet's surface. By understanding plate tectonics, we gain insights into geological hazards, natural resource distribution, and the evolution of Earth's landscapes. Let us continue to explore and appreciate the wonders of our dynamic planet, fueled by the movements of tectonic plates.