Monday, 28 February 2022

THE DAY DINOSAURS DIED




Credit – Scotese Paleomap project (this map shows the position of continents when the cretaceous Paleogene mass extinction occurred )


Do you know what happened on the very day dinosaurs died?

Well, according to the latest research done by geologists, it was the spring season in the Northern Hemisphere ( Autumn in the southern hemisphere) when the dino-killing asteroid smashed into the Yucatán Peninsula, off the coast of Mexico (present-day Chixulub).

In a paper recently published in nature, scientists used fossils from a site in North America in North Dakota’s southwest region known as Tanis.

The fossils were deposited by a seiche in a river. seiche is similar to a tsunami wave, but it happens inland, perhaps due to a strong earthquake.

The fossils of the fish present here contained glass spherules that were created due to the asteroid impact, which threw a large amount of molten rock material into space. The liquid rock crystallized, & cooled in space, and fell back down all over the planet. The fish that lived here ingested these and got trapped inside them.

Further researchers were able to figure out the season using the bones of fish.

The timing of the impact was also crucial from our point of view because, during spring, mammals hibernate underground and were very lucky when the asteroid struck

The asteroid that struck the Yucatán Peninsula 66 million years ago, was at least the size of Mount Everest. It managed to wipe out more than 70 % of all life present on Earth during that time, including the non-avian dinosaurs & giant reptiles.

This event is officially known as the "Cretaceous Paleogene (K- Pg) mass extinction".

The initial impact itself released energy equivalent to billions of nuclear weapons all at once. Thermal radiation melted & vaporized anything within a radius of 1500 km, & the impact debris caused the atmosphere to heat up.

The remainder of the energy was transferred into the Earth's crust, resulting in magnitude 11 earthquakes and volcanic eruptions.

Massive wildfires raged for months across the globe, releasing aerosols and soot into the upper atmosphere, causing temperatures to plummet and the planet to enter a period of darkness comparable to a nuclear winter. Global photosynthesis was halted due to a lack of sunlight, but fungi thrived on the corpses left behind.

Some debates are still raging on this issue, as the Deccan Traps of India were erupting before the Asteroid struck, either way, it seems that the Global ecosystem was already collapsing 66 million years ago.

You can learn more about this topic on -

Palaeocast | Palaeontology podcasts

BBC One and David Attenborough to reveal the final day of the dinosaurs - Media Centre

https://youtu.be/dFCbJmgeHmA

Thursday, 24 February 2022

MILITARY GEOLOGY

SOURCE - Bing

We may be due for a third world war. There are many examples of countries fighting over silly things. The reasons could be as mundane as a border defined based on a river that is prone to changing its flow direction according to changing conditions.

For example, along the north-eastern border of India, China has been trying to invade the state of Arunachal Pradesh. The Chinese may be trying to do so in search of new sources of minerals and other raw materials to support their economy. However, Indian geologists also know the significance of the area as they have already discovered precious deposits of uranium, lithium, helium, and rare earth elements.

Recently, the Russian Federation has declared War on Ukraine. There are many geopolitical reasons for this move by Russia, but one of the most significant might be to exploit the deposits of coal, iron ore, natural gas, manganese, salt, oil, graphite, sulfur, kaolin, titanium, nickel, magnesium, timber, and mercury.

Wednesday, 23 February 2022

ALWAR QUARTZITE


The Alwar Quartzite has been used to build monuments in Delhi and North India, such as the Purana Quila & Humayun’s tomb.

Quartz is resistant to weathering and can last for millennia. The monuments built by the rulers of Delhi stand as a testament to this.

These rocks come from the parts of the Aravalli Mountain Range exposed in Delhi.

Alwar Quartzite is exposed along the Delhi Ridge. This feature was once a continuous ridge over a century ago, but today it has been used up by mining done during urbanization and reduced to outcrops in the South Delhi region. These can be seen at Tughlaqabad, Okhla, Bhatti Mines area, Asola, Mandi, Greater Kailash, Vasant Kunj, Naraina, and the Buddha Jayanti Park.

At the turn of this century, legal mining was stopped around Delhi, due to environmental conditions 


Tuesday, 22 February 2022

RAMGARH CRATER

source - Google Earth

At Ramgarh, a quiet village in Rajasthan, a 4 km hole is punched into the ground. It is a circular impact crater rising abruptly (the wall is about a km high) in the plain area surrounded by vast agricultural fields.

This structure was first noticed in 1869. Since then, it has been studied by geologists and confirmed to be a meteorite impact crater later.

Apart from some temples, there are two water bodies present within the crater filled with rainwater. Migratory birds have been observed here. This area is considered a potential Geological Heritage Site in India as it is archaeologically, biodiversity-wise, and geologically important.

Coordinates—25°20'8.90"N, 76°36'23.70"E

 

Sunday, 20 February 2022

HOW DID COAL REALLY FORM, WAS IT CHANCE?

"fossil termite leftovers" by shadefenix is licensed under

India has vast coal reserves in the eastern river valleys. Estimates suggest this coal supply could last at least 500 years.

We have learned that coal is just the dead remains of ancient forests that fell to their deaths in peatland. We almost take it for granted because we don’t ask how it formed. Is this a simple explanation of the full story?

The problem with this matter is that palaeontologists know that the prime consumers of wood in the natural world, the termites, evolved only after an event called the "Great Dying." This was the worst mass extinction event in our planet’s geological history.

This period also coincides with the halting of the formation of coal! And this event is termed the "Coal Gap."

Although the distribution of plant life and the heterotrophs that depend on them changed dramatically after the Permian mass extinction, this does not explain why coal stopped forming so abruptly.

I am not saying that ever since the Great Dying, no coal has formed; it’s just that the amount and quality of coal which have formed during the time after the Coal Gap are not the same.

During the Carboniferous Period around 300 million years ago, there were unimaginably huge forests, which got that big in the first place due to the high temperatures and oxygen surplus.

As these forests died, they fell and piled up, not necessarily in swampy conditions, but just on the forest floor.

Over time, the underground pressure and temperature lithified them into a rock by driving out the volatile matter and leaving only a carbon residue.

So, the history of coal turns out to be more interesting than we ever thought.

Thursday, 17 February 2022

EDIACARAN SANDSTONE OF JODHPUR

In the Ediacaran age, Jodhpur Sandstone has been used for the construction of many buildings in north India.

The Jodhpur sandstone documents some of the earliest life forms that arose on Earth-like ginormous algal fossils, stromatolites and Ichonfossils (Ichonfossils are like tracks of a car’s tyre, using these we can come to know what kind of life forms were roaming around 600 million years ago), some of these precious fossils still remain unidentified and could be destroyed is the people involved in mining the sandstone are not told about this. These fossils could help Geologists decipher the evolution of life before the Cambrian explosion on the Indian subcontinent.

Sandstones are mostly made up of quartz, i.e. SiO2.

This sandstone manifests a range of colours from creamy pink to red and dark brown which is directly proportional to the amount of Iron oxide present in it.

This stone is quarried from Marwar near Jodhpur City

The Jodhpur Sandstone has been used in the past to build temples which still stand today and still continue to be used today for the construction of buildings such as educational institutions, government offices, medical facilities, 5 Star hotels etc. 

In the Ediacaran age, Jodhpur Sandstone has been used for the construction of many buildings in north India.

The Jodhpur sandstone documents some of the earliest life forms that arose on Earth, like ginormous algal fossils, stromatolites and ichnofossils (Ichonfossils are like tracks of a car’s tyre. Using these, we can come to know what kind of life forms were roaming around 600 million years ago). Some of these precious fossils still remain unidentified and could be destroyed if the people involved in mining the sandstone are not told about this. These fossils could help geologists decipher the evolution of life before the Cambrian explosion on the Indian subcontinent.

Sandstones are mostly made up of Quartz i.e. SiO2.

This sandstone manifests a range of colours from creamy pink to red and dark brown which is directly proportional to the amount of Iron oxide present in it.

This stone is quarried from Marwar near Jodhpur City

The Jodhpur Sandstone has been used in the past to build temples which still stand today and still continue to be used today for the construction of buildings such as educational institutions, government offices, medical facilities, 5 Star hotels etc. 

Wednesday, 16 February 2022

STROMATOLITES : THE OXYGEN PUMPS OF EARLY EARTH

At the dawn of life, our planet was almost uninhabitable and lacked a diversity of life forms.

The atmosphere was dense and still loaded with toxic gases that blocked the sunlight. This is known as the "faint sun hypothesis."

There was very little free oxygen gas available at that time.

And the only life on the surface was slimy mats of bacterial colonies known as stromatolites. They occur in varied shapes, from conical to horizontal, often forming reef-like structures.

Fossil evidence suggests they first appeared during the Archaean Eon and are still alive today. What a feat!

These microbes released immense quantities of oxygen into the Earth’s atmosphere, so much so that this event is called the "Great Oxygenation Event."

Around this time, thick beds of jasper and hematite were also being deposited. These are also known as "Banded Iron Formations."

The majority of the iron ore used all around the world comes from this particular time in the history of Earth.

Then fast forward a few billion years, right around 635 to 541 million years ago, from the start of the Ediacaran Period to the culmination of the Cambrian Period, something weird happened that put Earth’s biosphere into a frenzy and produced many kinds of life forms never seen before on the planet’s surface.

In India, stromatolite fossils occur in plenty at the following sites:

  • Inside the black chert of Chitradurga, Karnataka

  • Inside stromatolite bearing limestones of Bundelkhand, Son river valley & Salkhan Fossil Park in Sonbhadra district

  • Bhander, near Panna

  • The Devonian Rocks of Spiti

Monday, 14 February 2022

LARGEST MONOLITH IN SOUTH ASIA

Source - Google Earth

Have you ever seen a rock larger than a building? Here in India, we have lots of them. The largest natural monolith in South Asia is found in Karnataka. It’s locally known as Savandurga hill.

Hills like these served as the backdrop for films like "Sholay" & "The Passage to India".

There are many more such hills in South India, trekkers & adventurers from around the world come here to climb them.

These hills are super old, like 2.5 billion years old! they are made up of granite (granite is a volcanic igneous rock formed due to the cooling of magma below the ground). They are called "Closepet Granites" and they constitute the basement of the Dharwar Craton (a craton is an old piece of the continental crust).

Want to see for yourself?

Here are the coordinates 12°55'14.12"N 77°17'39.96"E

(just paste it in the Google Earth search bar).

VINDHYAN SANDSTONE THE WONDER OF INDIA

Sandstones from the Vindhyan ranges have been used to construct several national heritage structures in north India, especially government buildings and historical monuments.  



The oldest use of this variety of Sandstone has been documented at the Bhimbetika caves, a UNESCO World Heritage site, known for its beautiful cave art.  


Of course, monuments like the Stupas, Qutub Minar, Agra Fort & Red Fort, are also built of Vindhyan sandstone. 

This variety of sandstone has been used because it is chemically stable, resistant to physical weathering, and relatively easy to work on.

Thursday, 10 February 2022

ORIGINS OF TAJ MAHAL’S MARBLE


"Agra - Taj Mahal" by micbaun is licensed under CC BY 2.0

The Taj Mahal is made of a special type of marble called Makrana marble. It is locally known as "Sang-e-Marmar".

Makrana marble comes from a town with the same name in Nagaur district, Rajasthan, about 100 km from Jaipur.

Makrana Marble is a metamorphic rock. All metamorphic rocks start their journey as sedimentary rocks, in this case, limestone (calcium carbonate (CaCO3)).

For a long time, about 1450 million years ago (Proterozoic Eon), India was still part of a super-continent called Rodinia & the Aravalli ranges were very young.

Parts of India were submerged under the ocean where microorganisms were extracted.

Calcium and CO2 from the seawater precipitated into calcium carbonate (CaCO3), i.e., limestone.

When the oceans receded, new rocks were deposited on top of the limestone and it got buried deep inside the earth, where high temperatures and pressures compressed it into Makrana marble.

Over time, tectonic forces lifted up the rocks of this area and exposed them near the surface, where at present, over 800 quarries operate over an area of 30 km2.

Makrana marble is commonly used in flooring, making sculptures, and garden furniture & fountains, etc.


Wednesday, 9 February 2022

INTERNATIONAL YEAR OF CAVES AND KARST


The International Year of Caves and Karst is organised by the International Union of Speleology (UIS) 

The 2022 International Congress of Speleology has been postponed to July 24th to July 31st (2022) because of the ongoing pandemic.

Caves and karst landscapes are studied by many kinds of scientists, like geomorphologists and biologists.

The International Year of Caves and Karst would teach the public about

-How to best benefit from these natural resources

-to avoid their dangers

-to promote further research for better use and management of these critically important areas

Geomorphology is the subdiscipline of Geology that is devoted to the scientific study of the natural phenomena that have fashioned the land-forms on Earth’s surface and extraterrestrial planetary surfaces. Caves are important because they allow us to take a peek into the geological, meteorological, and environmental history of an area.

Caves are one of Earth’s greatest but least known natural wonders.

They provide water to millions of people, contain rare and important ecosystems, and preserve many of the world’s most important cultural and scientific sites.

Karst is a special type of landscape and is best known for having caves. Karst covers about 20% of the planet, and billions of people benefit from its resources and suffer from its challenges, like the sudden collapse of the land.

In the near future, there is a huge potential for exploring planetary sub-surfaces. Initially, robotic instruments like rovers and spider bots could be used for identification, investigation, and characterization of the environment inside these caves on the Moon and Mars, which would ultimately pave the way for in situ human exploration.


Tuesday, 8 February 2022

THE AMAZING GEO-HERITAGE OF RAJASTHAN


Mines in Rajasthan such as the lead-zinc mines of Zawar, Rajpura-Dariba,& Rampura-Agucha supply India’s industrial sector with invaluable raw materials.

During Bronze Age, Gold (18000 BC) & Copper (12000 BC) were used, Carbon dating of burnt wood shows that Zinc smelting happened 3040 ± 150 years ago

There is another well known rock in Rajasthan from the time of the Dinosaurs, the yellow limestone of Jaisalmer
Quarrying has been going on for decades and it is commonly marketed as “Yellow Marble”; Yellow limestone has good demand in the markets of countries in the Middle East, Taiwan, Morocco, USA, Europe, Australia, Africa, & New Zealand.

It is mostly used in making tiles, hotel counters, statues, furniture, mausoleums etc.

Sunday, 6 February 2022

ICHTHYOSAUR FOSSIL SITE IN THE CAUVERY BASIN

Ichthyosaurus were marine reptiles with a dolphin like appearance which lived in the oceans of the Mesozoic Era (251 million to 65.5 million years ago ) & had eyes the size of a football, fossil evidences show it gave birth to live young.

Dinosaur Eggs have been found in Ariyalur since 1860s

In Indifossils of these marine reptiles are found in Gujarat and Tamil Nadu.
Karai Badlands are one othe most fossil rich localities in south India, the area is barren and heavily eroded by intense rainfall and supports little vegetation.

In the past higher sea levels created a shallow sea here which began to expand into an Ocean as India, Australia and Antarctica began separating 137–132 million years ago, after the break-up of super-continent Pangea

Location — 12° 56′ 15.64″ N, 79° 18′ 58.82″ E. (Perambalur, Tamil Nadu, India)

The Geological Survey of India has identified this area as a potential National Geological Monument.
The Karai Badlands yield abundant fossils of brachiopods, belemnites, bryozoans, corals, algae, bivalves, cephalopods, gastropods, foraminifers, calcareous sponges, sharks & marine reptiles.

a: Oyster shells inside the body chamber of an Ammonite
b: Debris of Pycnodonte vesiculosa
c: Rhynchostreon shells
d: Pycnodonte vesicularis

Some well known finds from this area are listed below -

In 1989, Palaeontologists of GSI found fragmentary remains of the pelvis, vertebrae and the 2-metre-long shin bone of a giant Sauropod (Titanosaur) in Tiruchirapalli district & named it Bruhathkayosaurus, estimates put it at 34 metres long, 85 to 139 tonnes in weight

In 2011,conical teeth of Ichthyosaurus were found, later a Vertebra of an Ichthyosaurus was discovered in 2015 by students

➢ In 2013, tooth of a small crocodile (Simosuchus) were found, it 
was the size of a Dog & ate shoots, leaves & insects


Vertebra discovered in 2015
 

Listen to podcasts on this topic  -

How India's fossil treasures are turning to dust (Nature India Podcast)

Desi Stones & Bones


NEW MINERAL DISCOVERY 101 : Kernowite

  Kernowite: Mineral information, data and localities. (mindat.org) Kernowite Formula: Cu2Fe(AsO4)(OH)4 • 4H2O  Colour: Emerald-green  Cryst...