What is the Holocene Epoch?
Holocene Epoch is a geologic time scale (shorter than period but longer than age) which has been the most recent one. It began 11,650 years ago after the last glacial period and is still continuing. The holocene is the youngest of the two Epochs, the other one being Pleistocene Epoch, that are classified under the Quaternary Period. Some of the geologists also consider the current Holocene Epoch as an interglacial period within the Pleistocene Epoch. But the most unique feature is that the Holocene time coincides with the late and post-Stone age history of the human kind.
Different Classifications of Geographical Time Scale
The geological time scale is the classification system of the dating of chronology of the geological strata of the Earth over time. This classification system is used by the Earth scientists, geologists, and paleontologists to describe the time and any relationship that exists between the distinct events occurring in geologic history. The time scale and the classifications are done based on physical rock structures or rock layers, and the relationships along with the time when different organisms appeared, evolved and became extinct via the study of the fossilized remains and the imprints. The classification of the geological time scale is done into the following: Eons, Eras, Periods, Epochs and Ages. In this timeline classification, Eons are divided into Eras, Eras are further divided into Periods, Periods divided into Epochs and the Epochs are further subdivided into Ages. Thus, Holocene is an Epoch classified under the Quaternary Period, which comes under the Cenozoic Era, which is classified under the Phanerozoic Eon.
Under the classification of the Quaternary Period, comes the Pleistocene Epoch and Holocene Epoch. The Holocene is the Epoch which follows the Plestocene Epoch. It is also identified as a warm period and an interglacial period by the geologists, and Earth scientists. The striking feature of the Holocene time scale is the rapid proliferation, growth, and the impacts of Human species. The Holocene is characterized by all of the written history, technological advancements, development of many civilizations, and the current transition towards urbanization of the human population. The influence of humans is predominant in this Epoch and the impact on modern-era Earth and the ecosystems have led to the classification of the Holocene.
The Holocene Time-scale
The word Holocene finds its origin in the Ancient Greek language. Holocene meaning, according to Ancient Greek, is “whole new”. Breaking the word of Holocene into the Greek roots helps in identifying the holocene meaning. The term ‘Holo-’ is derived from the word Holos which means “whole”. The other ‘-cene’ is derived from the word kainos which means “new”.Thus, when combined together, the holocene meaning is “whole new”. The reasoning behind this, is the consideration that this epoch is entirely new as it is the most recent one and is still continuing. Also, the suffix ‘-cene’ is used for all the seven epochs that are classified under the Cenozoic Era.
According to the International Commision on Stratigraphy, the Holocene started 11,650 calibrated years ago before present. The Holocene Epoch is further sub-divided into five time intervals based on climatic fluctuations, which are also known as the Chronozones:
Preboreal: This is the time period between 10 kiloannum (ka) years - 9 ka before present (BP) (present i.e. 195)).
Boreal: This lies between 9 ka - 8 ka years BP
Atlantic: 8 ka to 5 ka years BP
Subboreal: 5 ka - 2.5 ka years BP
Subatlantic: 2.5 ka years BP.
During the time of the Holocene, there have been many changes that have taken place in terms of geology and climate which have shaped the current world. Also, the changes occurring due to Global warming in the last century itself has also impacted the natural progression of this Epoch. We will understand a few of these changes as we go through with the article.
Geological Changes During Holocene
The movements of the continent under the pressure of tectonic forces, has been less than a kilometre in the span of 10,000 years of Holocene. Another important change in the geology of the Earth, during this Epoch has been the rise in the sea-level. In the early part of the Holocene Epoch, because of the melting of ice, the sea-level rises about 35 m. In the later part of the Epoch also, the sea-level rises by another 30 m. Many of the areas of landmass above around 40 degrees North latitude that had been covered by ice of the Pleistocene Epoch were depressed by the weight of Ice. Hence, as the glacial period began to recede and the ice began to melt, the landmass rose by180 meters during the late Pleistocene and early Holocene Epoch. These landmasses still continue to rise.
Climate Changes During Holocene
As such the climate changes have been stable over the Holocene when compared to the cold period of Glaciation. The records collected from the ice cores have shown that before the start of Holocene there was a time period of warming happening globally which began after the end of the last of the ice ages and the cooling periods. The climatic changes became more and more regional and during the transition from the late glacial to Holocene the cold reversal known as Huelmo-Mascardi, began from South America in the Southern Hemisphere and most of the warmth flowed from south to north about 11,000 to 7,000 years ago. It is thought that this happened because of the residual glacial ice which was left in the Northern Hemisphere.
Early Human Settlements During Holocene
The Mesolithic age began with the beginning of the Holocene in most of Europe. In the regions of Middle East and Anatolia a very early neolithisation and Epipaleolithic period began. During this period the cultures that began include Hamburgian, Federmesser and Natufian culture. Also, some of the oldest inhabited places that are still existing such as the Tell es-Sultan (Jericho) in the Middle East began to be first settled. Other evidence of such settlements are given by archaeology at locations of Göbekli Tepe where proto-religion first began as long as 9th millennium BCE. Since then human courses have taken the known developments and continue till date.
It is noteworthy that, using terms like Holocene period, Holocene era or Holocene age, can be confusing as the terms period, era and age have different and definite meaning under the Geographical Time Scale classification system Hence, using Holocene or Holocene Epoch is more reliable and justifiable under such circumstances.
FAQs on Holocene Epoch
1. What is the Holocene Epoch?
The Holocene Epoch is the current geological epoch, which began approximately 11,700 years ago after the last major ice age. It is part of the Quaternary Period and is considered an interglacial period, meaning it is a warmer phase between two glacial periods. This epoch is particularly significant as it encompasses all of humanity's recorded history and the rise of civilizations.
2. What are the key characteristics of the Holocene Epoch?
The Holocene Epoch is defined by several key characteristics that distinguish it from previous geological times. The most important ones include:
- A relatively stable and warm climate compared to the fluctuations of the preceding Pleistocene Epoch.
- The retreat of massive continental glaciers, leading to a significant rise in global sea levels.
- The development and spread of modern forests, grasslands, and ecosystems.
- The emergence and global dominance of the human species, Homo sapiens, leading to widespread agriculture and urbanisation.
3. What major events define the Holocene Epoch?
The Holocene is marked by transformative events, primarily driven by both natural processes and human activity. Key events include the Neolithic Revolution (the development of agriculture), the extinction of large land mammals like the woolly mammoth and sabre-toothed cat, the rise of the first cities and civilizations in Mesopotamia, Egypt, and the Indus Valley, and more recently, the Industrial Revolution and the subsequent acceleration of global warming.
4. How does the Holocene Epoch differ from the preceding Pleistocene Epoch?
The primary difference lies in their climatic conditions and dominant life forms. The Pleistocene Epoch (2.6 million to 11,700 years ago) was characterised by repeated glacial cycles, or 'ice ages', with vast ice sheets covering large parts of the globe. It was also the age of megafauna. In contrast, the Holocene is a single, warmer interglacial period with a more stable climate, shrunken ice caps, and the rise of humans as the planet's dominant species, leading to different ecological and geological impacts.
5. Which animal species are characteristic of the Holocene Epoch?
The beginning of the Holocene was marked by the extinction of many megafauna from the Pleistocene, such as giant sloths and mammoths. The animal life of the Holocene is what we consider modern. A defining feature is the proliferation of animals that have been domesticated by humans, such as dogs, cattle, sheep, and pigs. Wildlife today, though diverse, is heavily influenced and often threatened by human activities, which is a key ecological theme of this epoch.
6. Why is the geological period we currently live in called the 'Holocene'?
The name 'Holocene' is derived from two Greek words: 'holos' meaning 'entirely' or 'whole', and 'kainos' meaning 'new' or 'recent'. Therefore, Holocene translates to the 'entirely recent' epoch. This name was chosen to signify a period defined by environmental conditions and life forms that are, in a geological sense, completely modern and directly connected to the world as we know it today.
7. What is the relationship between the Holocene and the proposed Anthropocene Epoch?
The Anthropocene is a proposed new geological epoch intended to mark the period where human activity became the dominant influence on Earth's climate and environment. While we are officially still in the Holocene, many scientists argue that the profound and lasting human impacts, such as nuclear fallout, plastic pollution, and human-driven climate change, have pushed the planet into a new state. The Anthropocene, therefore, can be seen as the most recent, human-dominated chapter that either follows or is emerging out of the Holocene.
