Geography Current Affairs

Surge in oxygen levels led to explosion of life on earth: Study

According to recently published study, boost in levels of oxygen may have caused three-fold increase in biodiversity (or biodiversification) during between 445 and 485 million years ago.

The study was conducted using geochemical proxies, high-resolution data and chemical signatures preserved in carbonate rocks formed from seawater. Using it, researchers were able to identify oxygen increase during Middle (or Darriwilian Stage- 460-465 million years ago) and Late Ordovician periods (mid-Katian stage- 450-455 million years ago).

Key Facts

According to study, this oxygenation is supported by two approaches that are mostly independent from each other. Other changes — such as ocean cooling, increased nutrient supply to oceans and predation pressures – also worked together to allow animal life to diversify for millions of years.

It was found that nearly 80% increase in oxygen levels where oxygen constituted about 14% of atmosphere during Darriwilian Stage and increased to as high as 24% of atmosphere by mid-Katian stage.

The explosion of diversity, recognised as Great Ordovician Biodiversification Event brought about rise of various marine life, tremendous change across species families and types, as well as changes to Earth, starting at bottom of ocean floors. It also brought on geological changes to the Earth.


This study suggests that atmospheric oxygen levels did not reach and maintain modern levels for millions of years after Cambrian explosion, which is traditionally viewed as time when ocean-atmosphere was oxygenated. Oxygenation of atmosphere and shallow-ocean took millions of years, and only when shallow seas became progressively oxygenated, major pulses of diversification able to take place.


India to host 36th International Geological Congress in 2020

India is going to host 36th International Geological Congress (IGC) in 2020 in NCR New Delhi. India had won the bid in 2012 at 34th IGC Brisbane, Australia to host the Congress in 2020.

Recently, delegation of International Union of Geological Sciences (IUGS) had visited India to discuss preparatory aspects of 36th IGC.

Key Facts

The 36th IGC to be held in New Delhi is jointly funded by Ministry of Mines and Ministry of Earth Sciences with active support of Indian National Science Academy (INSA) and science academies of India’s neighbouring co-host countries, Nepal, Bangladesh, Pakistan and Sri Lanka.

International Geological Congress (IGC)

The IGC is prestigious conclave of geoscientists from around world. It is considered as an Olympic of the International Geosciences fraternity. It aims to bring together the geo-scientific community across the continents and oceans. It is held once every four years (quadrennially) under aegis of IUGS through process of global bidding.

The first session of IGC was held in 1878 in France with an aim to provide global geological community with opportunity to create an organizational frame work for meeting at regular intervals. Since then, IGC have been hosted by 24 countries throughout the world at 3-to 5-year intervals. The 35th International Geological Congress was held at Cape Town, South Africa in 2016.

International Union of Geological Sciences (IUGS)

The IUGS is an international non-governmental organization devoted to international cooperation in the field of geology. It was founded in 1961. Currently geologists from 121 countries (and regions) are represented in IUGS through 121 adhering organizations. It is joint partner with UNESCO for International Geoscience Programme (IGCP).