History of Earth and Geosphere

History of Earth

• Earth came into existence around 4.567 billion years prior.
• The Earth initially was a molten surface
• The molten surface cooled
• Cooling of the molten surface led to the formation of a solid crust.
• Volcanic activity led to the development of the atmosphere.
• Oceans were created as condensed water vapor and cometary ice formed.
• Supercontinents came into existence, and fragmented as time passed.
• Ice ages occurred which resulted in shaping the planet.
• The last glacial period ended 10,000 years ago, which led to the present-day Earth.

Earth Subsystems

• The Earth consists of four interacting subsystems.
• The Geosphere includes the solid Earth and its interior layers.
• The Atmosphere is a gaseous envelope enclosing the planet.
• The Hydrosphere is made up of all water on Earth.
• The Biosphere comprises all living organisms and organic matter.
• These spheres consistently affect each other, forming the environment and sustain life.

Geosphere

• The Geosphere is the solid part of the Earth consisting of the Earth’s layers (continental and oceanic crust).
• Approximately 94% of Earth is oxygen, silicon, and magnesium.
• The geosphere's surface (crust) is not static and is constantly moving.
• The geosphere is the source of mined mineral resources.

Atmosphere

• The atmosphere can be described as the Earth being surrounded by a blanket of air.
• The atmosphere has four layers: troposphere, stratosphere, mesosphere, and thermosphere.
• The atmosphere extends over 560 kilometers (348 miles) from the Earth's surface.
• The atmosphere is mostly nitrogen (78%) and oxygen (21%).

Hydrosphere

• The hydrosphere includes all water on Earth.
• The ocean, streams, creeks, lakes, and rivers are the various bodies of surface water.
• Trapped water in the soil and groundwater are part of the hydrosphere.
• Water vapor found in the atmosphere is part of the hydrosphere.
• Glaciers and ice caps account for all the frozen water on Earth.
• 3% of the water on earth is fresh water.
• Around 70% of all fresh water is frozen glacial ice.

Biosphere

• The biosphere refers to the “life zone” of the Earth.
• It consists of all organic matter and living organisms (including humans).
• The biosphere is arranged into a hierarchy called the food chain.
• Primary producers can photosynthesize and are the base of the food chain.
• Transfer of mass and energy occurs from one level of the food chain to the next.

Layers of the Earth

• The four distinct layers underneath Earth’s surface are the crust, mantle, outer core, and inner core.
• The study of magnetic field and density calculation, and seismic waves has unraveled much information concerning Earth’s layers.
• Humans have only been able to drill 12 kilometers into Earth.

The Inner Core

• The inner core is a solid metal ball.
• It has a radius of about 1,220 kilometers (758 miles).
• It is primarily iron and nickel.
• It is located 6,400 to 5,180 kilometers (4,000 to 3,220 miles) beneath the surface.
• The temperature reaches to 5,400°C (9,800°F), with over 3 million times greater pressure than what’s on Earth's surface.

The Outer Core

• The outer core is a liquid layer.
• It is composed of iron and nickel, and lies 5,180 and 2,880 kilometers (3,220 to 1,790 miles) below Earth’s surface
• Radioactive decay of thorium and uranium heats the outer core.
• Liquid churns and forms turbulent currents
• This generates electric current producing Earth’s magnetic field, which reverses every 200,000 to 300,000 years.

The Mantle

• The mantle is the thickest layer of Earth and is nearly 3,000 kilometers (1,865 miles) thick.
• It is just 30 kilometers (18.6 miles) beneath the surface and consists mostly of iron, magnesium, and silicon.
• It circulates slowly
• The asthenosphere, a partially melted layer is contained in the mantle.
• The source of diamonds comes from deep within, sometimes to 700 kilometers (435 miles).
• Tectonic plates move on the asthenosphere.

The Crust

• The crust is thin, cold, brittle.
• Composed mainly of light elements like silica, oxygen, and aluminum.
• The crust is considered to be the shell of a hard boiled egg.
• It varies from 5 kilometers (3.1 miles) beneath the oceans, to 30 to 70 kilometers (18.6 to 43.5 miles) under the continents.
• Along with the upper mantle, it’s broken into tectonic plates, and causes earthquakes and volcanoes from convection currents or "slab pull”.

Rocks

• Rocks are formed from cooling and solidification of lava or magma.
• Accumulation and cementation of sediment form sedimentary rocks.
• Organic materials or broken down rocks are a source for sediments.
• Deep inside Earth's crust existing rocks become metamorphic due to heat and pressure.

Minerals

• Minerals are inorganic solids with a particular chemical composition and crystal construct.

Soils

• The weathered upper layer of the Earth's surface is called soil.
• Breakdown of organic matter and rocks create soils.

Weathering

• Weathering involves the breakdown of minerals, rocks, and soils.
• Physical (water and wind) and chemical (oxidation) processes breakdown rocks and minerals.

Erosion

• Erosion happens when weathered materials are carried away by wind, water, and ice.
• Settling and accumulation of eroded materials in a new location is deposition.

Plate Tectonics

• Earth's lithosphere consist of plates.
• Mountain building, volcanoes, and earthquakes happens when the plates move and interact.

Geochemistry

• The study of chemical composition and Earth’s processes and other celestial bodies is geochemistry.

Geology

• The materials, processes, and history of Earth is geology.

Rocks

• Rocks are a collection of minerals.
• Rocks have three groupings based on their formation and source.
• The three main categories are sedimentary, igneous, and metamorphic.

Sedimentary Rocks

• Fragments of eroded and weathered material deposits create sedimentary rocks.
• Sand, minerals, mud and pebbles are sedimentary rock fragments carried by wind or rivers.
• Fragments deposit in deserts, seas or lakes, compacting and solidifying over time, and form coal, limestone or conglomerate rocks.

Igneous Rocks

• Igneous rocks are created when magma cools.
• Extrusive and intrusive are the two main types of igneous rocks.
• Extrusive rocks have fine-grained crystals that cool rapidly on the surface.
• Intrusive rocks have large, visible, underground-forming crystals that cool slowly.
• Basalt from Giant's Causeway is extrusive, while granite, is intrusive and exposed.

Metamorphic Rocks

• Sedimentary, igneous, and existing metamorphic rocks can form metamorphic rocks.
• Hot temperatures and high pressure over millions of years cause the change.
• Shale can change into slate and limestone can turn into marble.
• Contact metamorphism is “baking” rocks with hot matter from a nearby igneous source.

Minerals

• Minerals are a naturally occurring substance with unique chemical and physical properties, atomic structure, and composition.
• Geological processes mix two or more minerals and creates rocks.
• Quartz, feldspar, and mica combine to form granite and sandstone makes compacted grains from minerals.
• Extracted economic minerals are a broader category used by construction, agriculture, manufacturing, and energy supply industries.

Exogenic Forces

• Exogenic factors are exogenetic agents that supply energy for processes at or near the Earth's surface.
• Exogenic factors include weathering, mass wasting, denudation.
• Exogenic factors are typically driven by gravity or force from the atmosphere.
• The earth’s external surface has deformation from tension from exogenic forces.
• Mass weathering, weathering, oxidation/reduction, hydrating, and erosion are all examples of exogenic factors.
• The term exogenic also pertains to external processes happening above Earth’s surface.
• Comet and meteoroid impacts, solar radiation, and the moon’s tidal force are exogenic phenomena.
• Those processes taking place on the planet's crust from exogenic forces refers to exogenic processes.
• Disclosing describes the process of denudation regarding all exogenic processes.

Endogenic Forces

• Internal forces or pressures within the Earth are endogenic forces.
• Surface upliftment, volcanoes, bending, rifting, earthquakes influence vertical and horizontal layouts.
• Subsidence, vertical and horizontal motions, volcanoes, land upliftment, faulting, folding, and earthquakes characterize endogenic forces.
• Mountain formation from extreme folding and affecting narrow bands of the Earth’s crust pertains to orogenic processes.
• Lifting or bending huge segments of the earth’s crust relates to epeirogenic processes.
• Local, small vibration level earthquakes also relate to endogenic forces.

Tectonic Plates

• Tectonic plates are large, rigid pieces of Earth's lithosphere.
• Tectonic plates float on the semi-fluid asthenosphere.
• Convection currents drive their movement at different rates.
• Interactions that collide, slide past, or pull apart are responsible for geological features.
• Mountains, volcanoes, and earthquakes are geological features.

Mineral Resources

• Considered a nonrenewable resource, mineral resources matter to mining metals from mineral sources, which form from rare geological processes
• Demand for conventional and critical metals is on the rise because of net-zero policies and climate change goals
• Economic geologists must improve exploration efforts, focusing on province selection in order to make the discovery of new ore deposits, before applying costly chemical and geophysical methods.

Energy Resources

• Materials can produce heat, power life, move objects, or generate electricity classify them as energy resources.
• Fuels store energy.
• Most of today’s energy is derived from non renewable fossil fuels, which pose challenges to the environment.
• All energy sources, except direct solar energy, depend on materials on Earth.