Proterozoic Eon - The Age of Supercontinents

The Paleoproterozoic Era – meaning "ancient Proterozoic" – was a time of major geological and biological change. The first supercontinents assembled, the atmosphere became oxygenated, and the first complex cells evolved.

• Great Oxidation Event (c. 2.4–2.0 Ga): The oxygen produced by cyanobacteria during the Archean finally accumulated in the atmosphere, creating the ozone layer that shielded the Earth from harmful ultraviolet radiation. This was one of the most important events in Earth's history, making it possible for life to eventually colonise the land.
• Supercontinent Columbia (c. 2.5–1.8 Ga): The first well-documented supercontinent, Columbia (also known as Nuna), assembled during the early Proterozoic. It included the Dharwar Craton, the Bastar Craton, the Singhbhum Craton, and other cratons that would later form India. Columbia was assembled through continent-continent collisions, including the one that formed the Eastern Ghats Mobile Belt.
• Eastern Ghats Mobile Belt (c. 2.5–1.6 Ga): Continental collisions and mountain-building created the Eastern Ghats Mobile Belt, which runs along the eastern margin of Telangana. This belt contains khondalites (garnet-sillimanite gneisses) and charnockites (granulite facies rocks) that formed deep in the Earth's crust.
• Eukaryotes Evolve (c. 2.0–1.2 Ga): Around 2.0 billion years ago, eukaryotes – cells with a nucleus and other membrane-bound organelles – evolved through endosymbiosis. This evolutionary innovation made multicellular life possible.
• Columbia Breaks Apart (c. 1.8–1.3 Ga): Around 1.8 billion years ago, Columbia began to break apart, creating new oceans and separating cratons. The Dharwar Craton was part of this rifting event, which created the conditions for the formation of new sedimentary basins.
• Telangana Connection: The Eastern Ghats Mobile Belt – a zone of intense deformation – formed during this era along the eastern margin of Telangana. The Godavari and Krishna grabens – rift valleys where sediments accumulated – began to form during this time, preserving evidence of ancient environments. These basins later became important for coal and diamond exploration.

The Mesoproterozoic Era – meaning "middle Proterozoic" – was a time of continued continental evolution and the emergence of the first multicellular life.

• Columbia Breakup Continues (c. 1.3–1.0 Ga): The breakup of Columbia continued, creating new oceans and separating cratons. The Dharwar Craton was part of this rifting event, which created the conditions for the formation of new sedimentary basins.
• Godavari and Krishna Grabens (c. 1.6–0.8 Ga): The Dharwar Craton was overlain by sedimentary basins, including the Godavari and Krishna grabens – rift valleys where sediments accumulated, preserving evidence of ancient environments. These basins later became important for coal and diamond exploration.
• First Multicellular Life (c. 1.2–0.6 Ga): The first multicellular organisms began to appear – simple colonies of cells that worked together for mutual benefit. These included early algae and sponges. This was a major step in the evolution of life on Earth.
• Supercontinent Rodinia (c. 1.0 Ga): By the late Mesoproterozoic, a new supercontinent – Rodinia – assembled. Rodinia included nearly all of Earth's continental crust, including the Dharwar Craton, which was located near the equator. Rodinia was surrounded by the vast global ocean Mirovia. The assembly of Rodinia was a major tectonic event that affected the geology of the entire planet.
• Telangana Connection: During the Mesoproterozoic, the Dharwar Craton was part of the supercontinent Rodinia, located near the equator. The Godavari and Krishna grabens continued to accumulate sediments, preserving evidence of ancient environments. The Dharwar Craton's position near the equator during this time would later influence the evolution of life in the region.

The Neoproterozoic Era – meaning "new Proterozoic" – was the final era of the Proterozoic Eon. It was a time of dramatic geological and biological change – the breakup of Rodinia, the Snowball Earth events, and the emergence of the first complex, multicellular life.

• Rodinia Breaks Apart (c. 750–633 Ma): Starting around 750 million years ago, Rodinia began to break apart. The Dharwar Craton was separated from other landmasses by the opening of the Mozambique Ocean (an ancient ocean that existed between East Africa and India). This rifting created new coastlines and altered ocean currents, influencing the global climate.
• Snowball Earth (c. 750–580 Ma): Earth experienced Snowball Earth events – periods of extreme glaciation when ice covered much of the planet. These events may have driven the evolution of multicellular life by creating extreme environmental pressures. While the Snowball Earth events affected the entire planet, the Dharwar Craton was located near the equator during this time, which may have allowed life to survive in refugia.
• Supercontinent Pannotia (c. 633–541 Ma): During the late Neoproterozoic, a new supercontinent – Pannotia – formed. Pannotia was a short-lived supercontinent that included most of the landmasses of the southern hemisphere, including the Dharwar Craton (now part of the Indian Shield). Pannotia was surrounded by the global ocean Panthalassa. However, Pannotia began to break apart almost immediately, creating the configuration of continents that would persist into the Phanerozoic.
• Ediacaran Biota (c. 600–541 Ma): The Ediacaran Period saw the emergence of the first complex, multicellular organisms – the Ediacaran biota. These strange, soft-bodied creatures were unlike anything alive today. They included Dickinsonia (a flat, segmented organism), Charnia (a frond-like organism), and many others. The Ediacaran biota was the first major radiation of complex life on Earth.
• Gondwana Assembly (c. 600–541 Ma): The breakup of Pannotia created several smaller continents, including Gondwana. India (including the Dharwar Craton) was part of Gondwana, which also included South America, Africa, Antarctica, and Australia. Gondwana would persist as a major landmass until its breakup in the Mesozoic Era.
• Telangana Connection: During the Neoproterozoic, the Dharwar Craton moved from the equator to the southern hemisphere as part of Gondwana. The opening of the Mozambique Ocean separated the Dharwar Craton from East Africa. While the Ediacaran is well-represented in other parts of the world, no Ediacaran fossils have yet been discovered in Telangana – a frontier for future research.