The earth is a very old planet and has evolved through a series of events. These events were positive as well as negative. Many geological events have occurred on the earth that have shaped it the way it is today. Geologic events are known to occur very slowly as a result of tectonic forces on the earth. Some major geological events have led to the disruption of lives and caused havoc to species. In this article, we are going to discuss what is an example of a geological event, and examples of geological hazards.
1. What is considered a Geological Event?
A geological event is something that can significantly change the physical landforms on the earth. These events happen in the crust of the earth. This happens due to the internal force of the earth that alters the surface of the earth and the structure underneath. This is a natural event. In this event, one or more geological processes act and modify the geological structures. They transform the physical landforms on earth.
Geological events can also be defined as the movement of tectonic plates under the surface of the earth. Heat is considered an important part of any geological event to occur. If you want to know what is an example of a geological event, then keep on reading. (See How Convection Current causes the Lithospheric Plate to move?)
2. What are the 4 Geological Events?
The geological events can be classified into 4 eras. These eras marked the emergence, evolution, and extinction of various species on the earth. These eras have a diversity of all life forms. Some of the main eras are:
- Precambrian Era: The Precambrian Era started when the earth was formed 4.6 billion years ago. It lasted until 542 million years ago. There was no life on earth till the end of this era. Single-celled organisms came into existence at the end of this era which gradually led to the emergence of more organisms.
- Paleozoic Era: This era lasted from 542 million to 250 million years ago. It began with the Cambrian Explosion. It was a rapid period of speciation that kicked off many life forms on earth and large amounts of life forms moved from the ocean onto the land. With the end of this era, came the largest mass extinction in the history of life on Earth that wiped out 95% of marine life and nearly 70% of life on land.
- Mesozoic Era: Mesozoic Era lasted from 250 million until 65 million years ago. In this era, many new species emerged after the mass extinction in the Paleozoic era. Dinosaurs were the major part and this era was termed the age of the dinosaurs. Small mammals emerged and birds also evolved from dinosaurs. The climate was humid and many plants grew on the earth. The end of this era was also marked by mass extinction which wiped off major life forms of this era.
- Cenozoic Era: The Cenozoic Era began around 65 million years ago and is continuing till the present. The animals that could survive the mass extinction in the Mesozoic Era grew and became dominant. The climate became cooler and drier which led to the species adapting to it. All life species evolved during this period including humans. This period will most likely not end until another mass extinction takes place. Still, looking for: what is an example of a geological event? Well, keep reading.
3. What are Some Major Geological Events?
Some major geological events in the history of earth are:
- 4600 million years ago – Planet Earth formed.
- 4500 million years ago – Earth’s core and crust formed
- 4400 million years ago – The Earth’s first oceans formed
- 3850 million years ago – The first life appeared on Earth
- 1500 million years ago – Oxygen began to accumulate in the Earth’s atmosphere
- 700 million years ago – The first single-celled animals evolved
- 530 million years ago – The first vertebrates (fish) evolved.
- 400 million years ago – The first land plants evolved
- 350 million years ago – The first land vertebrates evolved
- 225 million years ago – The first time when dinosaurs evolved from lizards.
- 65 million years ago – The dinosaurs went extinct
- 130,000 years ago (0.13 million years ago) – Modern humans evolved
4. What was the Last Major Geological Event?
The last major geological event happened in the Mesozoic Era around 65 million years ago that wiped out major life forms on earth. This includes the extinction of dinosaurs along with many other species. This was caused by the after-effects of the meteorite impacts. The impacts led to the occurrence of earthquakes, tsunamis, and volcanic eruptions that completely changed the environment of the earth. There was dust all around which blocked the sunlight from reaching the atmosphere. This led the plants to die and the food chains collapsed. After the extinction of dinosaurs, mammals evolved and started filling the evolutionary niches left behind. (See What Was Before Dinosaurs?)
5. What is an Example of a Geological Event?
Examples of geological events are:
- Volcanic eruptions
6. Which Two Geologic Events occur very slowly as a result of Tectonic Forces?
The following two geologic events occur very slowly as a result of tectonic forces and they are:
- Seafloor spreading: Seafloor spreading is caused by the splitting of tectonic plates apart from each other. Tectonic plates are the large slabs that are present in the Earth’s lithosphere. The spreading of the seafloor causes the formation of mountains or elevated areas of the seafloor. These activities are the result of mantle convection which is the slow and churning motion of Earth’s mantle. This Seafloor spreading usually takes place at divergent plate boundaries.
- Mountain-range formation: Mountain ranges are formed as a result of the tectonic plates. These also cause the formation of volcanic mountains which are formed when a tectonic plate is pushed beneath another. The magma is forced to the surface which leads to the formation of mountains. Examples: Mount Fuji in Japan, and Mauna Kea in Hawaii.
7. Is an Earthquake a Geological Event?
What is an example of a geological event? An earthquake is considered one of the major geological events. It is caused by a sudden slip in the fault, which is the fracture along the block of crust. The tectonic plates beneath the earth always move slowly, but they can get stuck at their edges due to friction. An earthquake is caused when the stress on the edge overcomes the friction. (See What are Geologic Features?)
8. Which Event causes an Earthquake?
An earthquake is caused by the meeting of two plates at plate boundaries. It is a sudden and catastrophic failure of rocks under stress. The sudden slipping of two blocks past one another horizontally or vertically. The area of slipping of blocks is known as the fault. Must see what landform is created when two continental plates collide?
There are three types of faults:
- Normal: Normal faults are found at divergent plate boundaries. This is where the tectonic plates move away from each other.
- Thrust or Reverse: The Thrust or Reverse faults are found at convergent boundaries where tectonic plates are towards each other and collide.
- Strike-slip: Strike-slip faults are found at transform plate boundaries where two tectonic plates slide horizontally past one another.
9. What is a Geological Natural Disaster?
Apart from explaining what is an example of a geological event, you must know that a geological natural disaster is an event that is caused by destructive activities that originate within or are caused by the processes of the earth. Examples of geological natural disasters are earthquakes, tsunamis, volcanic eruptions, and so on. These events have a direct impact on human lives. It leads to the loss of life, damage to infrastructure and the environment, and causes hardships for humans including economic well-being. Geological natural disasters have a negative impact on our lives and lead to the loss of worth of billions.
There are two types of geological natural disasters. They are gravitational and meteorological disasters.
- The gravitational disaster includes landslides, rockfalls, debris flows, or avalanches since rock, mud, or snow masses slide down because of gravity.
- Meteorological disasters include heat, drought, forest fires, storms, floods, and high water or heavy rain.
10. What are Examples of Geological Hazards?
You already know what is an example of a geological event, now take a look at the following examples of geological hazards:
- Forest fires,
- Heavy rain,
- Debris flows, and
Geological events are deadly as we have discussed above and they do not spare anyone if they occur. Some of the great mass extinctions of the past were because of these events only and probably, the current era will also end due to the result of these events. Hope you are clear about what is an example of a geological event, major geological events, and their impact. (Also read Where is the Youngest and Oldest Crust?)