Physical Geography

Physical and chemical flows across the Earth’s surface, the processes that determine these fluxes, and the resulting landscapes are all considered in Earth Surface Processes. The Earth’s surface serves as a diffusive border between the atmosphere and the lithosphere, resulting in a global topography shaped by tectonic and climatic processes. The transformation of rock into sediment by weathering and erosion, as well as the movement and deposition of sediment, typically from continents to seas, are the greatest surface fluxes that come from this interaction. Controlling this flux and understanding how it has changed through time is a first-order concern for the Geosciences, which spans geomorphology, sedimentology, stratigraphy, mountain formation, and large-scale geochemical cycling.

Layers of the Earth

To understand plate tectonics in its entirety, one must first understand the Earth’s strata. Unfortunately, humans lack firsthand knowledge of what is beneath the surface; most of what we know is based on models, seismic waves, and hypotheses based on meteorite material. Based on chemical composition and physical properties, the Earth can be split into layers.

Chemical Layers

The Earth is divided into three major groups depending on its chemical makeup. Although there are numerous variations in composition around the globe, only two major alterations occur, resulting in three unique chemical layers.

Crust

Humans presently live on the crust, which is the outermost chemical layer. The crust is divided into two types: continental crust, which is low density and similar in composition to granite, and oceanic crust, which is high density (particularly when cold and old) and similar in composition to basalt. Because of the increased heat, rocks in the lower crust become more ductile and less brittle. As a result, most earthquakes occur in the higher crust.

Mantle

The mantle is the layer that exists between the crust and the core. It is the largest layer in terms of volume, ranging from the crust’s base to a depth of nearly 2900 km. The majority of what we know about the mantle comes from seismic waves, while some direct information can be gleaned through ophiolites, which are pieces of the ocean floor lifted to the surface. Xenoliths, small bits of lower rock transported to the surface by eruptions, are also carried within magma. These xenoliths are made of peridotite, a rock that is ultramafic on the igneous rock scale. Peridotite is thought to make up the majority of the mantle.

Core

Iron, nickel, and oxygen make up the majority of the Earth’s core, which contains both liquid and solid components. It was discovered by looking at seismic data in 1906. The discovery that the core is mostly metallic iron took a combination of modelling, astronomical understanding, and seismic data. Meteorites have a lot more iron than ordinary rocks. If meteoric material formed the Earth, the core would have formed as dense material (containing iron and nickel) sank to the Earth’s centre via gravity as the planet formed, fiercely heating the Earth.

Earth’s Surface Features

The features on the Earth’s surface are the result of both constructive and destructive processes. Landforms grow due to constructive forces. A new landform is created when a new volcano erupts. Landforms are worn down by destructive processes. Mechanical and chemical weathering, as well as erosion, gradually transform once-high mountains into smooth flat plateaus.

• The continents are huge geographical masses that stretch from high mountain peaks to the sea

• Ocean basins go from the continent’s boundaries down steep slopes to the ocean floor and into deep trenches

Continents

The oldest continental rocks date back billions of years, so the continents have had plenty of time to change. Landforms are physical features on the Earth’s surface that evolve due to constructive forces. Crustal deformation produces hills, valleys, and other landforms when crust compresses, pulls apart, or slides past another crust. When continents collide, one slab of oceanic crust plunges beneath another, or a slab of continental crust plunges beneath another, a chain of volcanoes forms. Landforms such as deltas are formed by sediment deposition.

Volcanic eruptions can sometimes be destructive, causing landscapes to disintegrate. Weathering and erosion are harmful forces that change terrain. Water, wind, ice, and gravity are all powerful erosion forces.

Ocean Basins

All of the ocean basins are less than 180 million years old. The continental margin is formed of continental crust, even though the ocean basins begin where the water meets the land. The ocean floor is not completely flat. The mid-ocean ridge, a mountain range that spans through much of the ocean basin, is the most prominent feature. Ocean trenches, many of which are located around the Pacific Ocean’s edge, are the deepest spots on the planet. Volcanic chains can also be located in the middle of the oceans, like in the Hawaiian Islands. On the ocean floor, flat grasslands with mud-covered features can be discovered.

Changing Earth

The surface of the Earth varies throughout short and long time periods. New features are formed by constructive factors such as volcanic activity or crust uplift. Existing landforms are distorted and destroyed by destructive factors such as water, wind, ice, and gravity. Volcanic activity creates new seafloor beneath the oceans, while existing seafloor is destroyed in trenches.

Conclusion

We can conclude that the atmosphere, water, biota, and tectonics interact at the Earth’s surface to transform rock into landscapes with different features that are critical to the function and existence of water supplies, natural hazards, climate, biogeochemical cycles, and life.

The study of earth surface processes and the landscapes they form is full of unanswered issues and prospects for fundamental scientific advancements, as well as understanding and predicting the relationships, causes, and effects of these processes. Scientists who study earth’s “surface processes” have a unique and novel ability to contribute to a better knowledge of how the planet’s surface changes through time and the resolution of critical environmental concerns that may arise as a result of these changes.