What is Meghalayan Age YouTube Lecture Handouts for Rajasthan PSC

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Watch video lecture on YouTube: How to Write a Good Answer? Meghalayan Age How to Write a Good Answer? Meghalayan Age
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Image - 1 of Meghalayan Age

Image - 1 of Meghalayan Age

Image - 1 of Meghalayan Age

How We Identify Ages?

  • By geological age dating – rocks (age, time, material and major event)

  • 66 million years ago - switch in period from the Cretaceous to Tertiary was "golden spike" & is represented by traces in sediments of the element iridium.

  • For the Meghalayan, the spike is epitomised in specific chemical signatures – triggered by shifts in ocean and atmospheric circulation

Image - 2 of Meghalayan Age

Image - 2 of Meghalayan Age

Image - 2 of Meghalayan Age

  • Evidence: Stalagmite rock formations in Krem Mawmluh Caves (Meghalaya) – MAP

  • Mawmluh cave in Meghalaya is located at an elevation of 1,290m and is among the top ten longest and deepest caves in India.

  • Stalagmite collected from here has shown that the conditions in the cave were suitable for preserving chemical signs of the transition in ages.

  • The stalagmite has now been tagged a Global Boundary Stereotype Section and Points (GSSP), the first formally ratified marker of a geological time period change in India.

  • Tested by the sub commissions of the International Commission on Stratigraphy under the chairmanship of Professor David Harper, Durham University, UK.

Refer -

Watch video lecture on YouTube: Geological Time Scale with reference to India - 4 Eras & 10 Periods Geological Time Scale with Reference to India - 4 Eras & 10 Periods
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Longest unit is EON (last eon is Phanerozoic – visible life)

  • Holocene is subdivided into three parts (identified by sediments accumulated on Lake Floor, glacial ice and more)

  • Greenlandi an: 11,700 to 8,200 years

  • Northgrippi an: 8,200 to 4,200 years ago

  • Meghalayan: 4,200 years ago to present (by International Union of Geological Sciences - IUGS)

  • The lower boundary of the Greenlandian and Northgripppian stages are defined at specific levels in Greenland ice cores.

  • The lower boundary of the Meghalayan Stage is defined at a specific level in.

  • The ice cores and the stalagmite are now identified as a stalagmite from a cave in northeast India international geostandards, and have been placed in protected archives accessible for further study.

Refer -

Watch video lecture on YouTube: Karst Topography (By Underground Water) - Formation, 8 Erosional and 9 Depositional Landforms Karst Topography (By Underground Water) - Formation, 8 Erosional and 9 Depositional Landforms
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and

Watch video lecture on YouTube: Goh Cheng Leong Chapter 8: Limestone and Chalk Landforms Goh Cheng Leong Chapter 8: Limestone and Chalk Landforms
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Decision to define these new stages of the Holocene Series and thus the three new corresponding ages of the Holocene Epoch allows for an update to the International Chrono stratigraphic Chart, which depicts the timeline for the earth’s full geologic history.

Image of Phanerozoic

Image of Phanerozoic

Image of Phanerozoic

  • Meghalayan age began when a mega-drought devastated civilizations across the world, whose effects lasted two centuries.

  • It severely disrupted civilizations in Egypt, Greece, Syria, Palestine, Mesopotamia, the Indus Valley, and the Yangtze River Valley.

  • This is the first time a geological time scale change has been linked to cultural event – in this case the collapse of civilizations.

Image of Human Civilziation

Image of Human Civilziation

Image of Human Civilziation

Idea was raised in a paper 6 years ago

Critics: Mega drought only affected civilizations in the Middle East and North Africa, India and parts of China,” and leaves out “the huge civilizations that existed in the Americas and Africa and Northern Europe.”

Image of Critics

Image of Critics

Image of Critics