Supercontinents

A great landmass which was thought to be in the geological past, splitting into fragments drifting apart and again colliding into one another is called a supercontinent.1. VAALBARA -First ever made continent was Vaalbara which was 3.6 billion years old, it was named after kaapvaal and Pilbara which were the most ancient cratons present on that land mass. Kaapvaal is in Africa and Pilbara is in western Australia.2. UR- A supercontinent which was 3000 m.y.a and it was smaller than modern day Australia.3. KENORLAND- 2700 m.y.a famous events were HURONIAN GLACIATION. Also known as SNOWBALL   EARTH.Responsible for formation of phytoplanktons.and VREDEFORT impact.4. COLUMBIA- Also called as NUNA . Period between Snowball Earth and subsequent Oxidation is called as THE BARREN BILLION.5. RODINIA- 1130 m.y.a.SECOND SNOWBALL EARTH.Also known as NEOPROTEROZOIC GLACIATION.6. PANNOTIA- 750 m.y.aThe formation of Pannotia was associated with the breakup of Rodinia into Proto- Gondwana and Proto-Laurasia. Two oceans were PANTHALSSA and Pan-African Ocean.7. PANGEA- One of the Youngest Supercontinent of all time , there are plenty of evidences of this Supercontinent. Like marine fossils from TETHYS OCEAN can be observed in Himalayas.

1. SUPERCONTINENTS Presented by- Mayank Joshi

2. A Seminar Presentation on “ Supercontinents ” Date of Presentation: 28th March 2019 Submitted by: Mayank V. Joshi MSc . Tech(Applied geology) II semester Guided by Biswajit Hazarika Assistant Professor POST GRADUATE DEPARTMENT OF GEOLOGY, RASHTRASANT TUKADOJI MAHARAJ NAGPUR UNIVERSITY, NAGPUR Year: 2018-2019

3. INDEX Introduction Vaalbara Ur Kenorland Columbia Rodinia Pannotia Pangea Conclusion References

4. WHAT IS THE SUPERCONTINENT ? A great landmass thought to have existed in the geological past and to have split into smaller landmasses, which drifted and formed the present continents Supercontinent cycles are semi regular groupings of the planet's landmasses into single or large continents that remain stable for a period of time, then disperse, and eventually come back together as new amalgamated landmasses with a different distribution .  

5. VAALBARA Considered possibly the first continent , since it was the ONLY continent it is also considered a Supercontinent.   Age - 3.3 to 2.8 Billion years Eon- Archean . Considered Speculative. The size and shape of this formation are uncertain and for the most part are only hypothetical . The name of the Vaalbara supercontinent origins from the endings of the two most ancient cratons on the planet: Kaapvaal (located mainly in South Africa) and Pilbara (same named region in Northwestern Australia). They are highlighted in red on the modern photo of the Earth.

6. REMAINS OF VAALBARA

7. UR Smallest of Supercontinents. Existed 3 billion years ago . Formed in Neoarchean Era  It is called Ur from the German prefix “ ur ” which means “original”, “fountainhead”.  Classified as the earliest known landmass. Ur, however, was probably the largest, perhaps even the only continent three billion years ago. “Today, Ur lives on as part of India, Madagascar, and Australia ” (Wilkins, 2011). 

8. UR “ longest-lived landmass this planet will ever see” (Wilkins, 2011). Remained until the break up of Pangea . Mantle was hotter and Sun was cooler, eventually Sun warmed up and matle cooled down. It was smaller than Australia is today , an older rock formation in Greenland belts dates back from Hadean times.

9. PRESENTATION OF UR

10.   KENORLAND    2.7 billion years ago. Formed from Neoarchaean cratons . The name was given in accordance with the Kenoran orogeny . As it had mountains from which heat was escaping caused chemical weathering, which decreased CO 2 levels in the atmosphere , resulting in FIRST SNOWBALL EARTH . Which had many glaciers HURONIAN GLACIATION - This was a series of glaciations and warming cycles , which reduced chemical weathering which helped carbon dioxide to build up resulting in THE GREAT WARMING . This glaciations was put to an end by the breaking of KENORLAND.

11. KENORLAND Mantle heath beneath the supercontinent eventually caused it to rift apart. It was marked by invading sea, temperature mediation resulting in glacier melt, increased rainfall and erosion. Organic nutrients such as phosphorus and iron were free to swim In the sea and later became essential for phytoplankton's which released enormous amount of Oxygen and there was proliferation of life. This was all put to an end by VREDEFORT IMPACT , which infact is the largest verified impact crater on Earth.

12. ASSUMPTION OF KENORLAND

13. COLUMBIA 1.8 billion years ago . Up to 1.4 billion years, Proterozoic eon and Paleoproterozoic era, that is from the beginning of statherian period up to end of ectasian period. 12,900km North to South, 4,800km East to West. Also called as NUNA. “It consisted of the proto- cratons that made up the former continents of Laurentia , Baltica , Ukrainian Shield, Amazonian Shield, Australia, and possibly Siberia, North China, and Kalaharia as well ”. Period between Snowball Earth and the subsequent oxidation events Is called “THE BARREN BILLION.”

14. COLUMBIA

15. RODINIA   Between 1.1 billion and 750 million years ago . It was Proterozioc eon and it lasted from stenian to tonian to cryogenian period. Little is known about geographical configurations Multiple theories “Existed before life colonized dry land, and, since it predated the formation of the ozone layer, it was too exposed to ultraviolet sunlight for any organism to inhabit it”. Second Snowball Earth . And also known as Neoproterozoic glaciations .

16. This is how Rodinia approximately looked like

17. PANNOTIA 750 million years ago . Eon – Proterozoic . Era- Neoproterozoic Also known as Vendian . Short-lived (60 million years) Active rifting caused it to split into 4 continents.  during the existence of Pannotia there were two proto-oceans — Panthalassa and the Pan-African ocean , which surrounded the supercontinent.

18. LAND DISTRIBUTION OF PANNOTIA

19. PANGEA 300 million years ago Pangaea existed in the late Paleozoic and early Mesozoic 300 mya . At that time, the supercontinent united all modern continents into one. Many of today’s mountain ranges were formed at the time of collision of continents and lithospheric plates. Most commonly known supercontinent Fossil evidence of supercontinent. The time existence of Pangea was – Ordovician –Silurian-Devonian-Carboniferous-Permian-Triassic-Jurassic Period.

20. PANGEA This supercontinent saw appearance of of algae and mollusks, spread of plants and fishes, first land vertebrete occurred In devonian , outlines of pangea , Greatest mass extinction in Earth’s history, climate warming and appearance of large marine predators and reptiles and amphibians. And lastly spread of Dinosaurs. It breaked down into Laurasia and Gondwana . Modern Eurasia and Northern America formed from Laurasia and Africa, India, South America, Australia and Antarctica formed from Gondwana .

21. PANGEA SUPERCONTINENT

22. REFERENCE Supercontinent definition - Retrieved from Earth observatory - ( https://www.earthobservatory.sg/faq-on-earth-sciences/what-supercontinent ) . supercontinents in Earth’s History ( https://www.researchgate.net/publication/222049723_Supercontinents_in_Earth_History ) ( (Page no. 357-368 · Published on - July 2003 ) Geological history of supercontinents on planet earth ( https://en.wikipedia.org/wiki/Supercontinent ) . M. Santosh , L. Wang and T Kusky . Supercontinent cycles ( Pages 1403-1423 | Accepted 24 Sep 2010, Published online: 12 Feb 2011 ) ( https://www.tandfonline.com/doi/abs/10.1080/00206814.2010.527682 ). Images From : ( https://the-dialogue.com/en/en33-earths-supercontinents/ ) .

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