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Subject: Geography

  • Kallakkadal: Coastal Flooding Phenomena in Kerala

    Why in the news?

    • Coastal areas of Kerala, including Alappuzha, Kollam, and Thiruvananthapuram districts, are grappling with flooding caused by high sea waves, known as swell waves or Kallakkadal in Malayalam.
    • The recent swell surge occurred following a low-pressure system originating in the South Atlantic Ocean, leading to the formation of waves reaching heights of up to 11 meters.

    What is Kallakkadal?

    1. Origin and Meaning:
    • Kallakkadal refers to coastal flooding during the (April-May) pre-monsoon season.
    • It is caused by ocean swell waves on the southwest coast of India.
    • The term “Kallakkadal” originates from Malayalam, combining “Kallan” (thief) and “Kadal” (sea), denoting the sea’s unexpected intrusion akin to a thief.
    • In 2012, the term was formally approved by the UNESCO (United Nations Educational, Scientific and Cultural Organization).
    1. Causes:
    • These waves stem from distant storms, such as hurricanes, generating significant energy transfer from the atmosphere to the water.
    • Kallakkadal typically results from strong winds in the southern Indian Ocean, generating ocean swells that travel northward towards the Kerala coast.

    Features of Kallakkadal

    • This phenomenon occurs mostly during pre-monsoon season and sometimes during post monsoon.
    • It continues for a few days.
    • It inundates the low lying coasts.
    • Initially sea recedes before the surge.
    • During high tide the run-up, water level can reach as much as 3–4 m above Maximum Water Level (MWL).

    How is it distinct from Tsunami?

    • Nature of Phenomenon: Kallakkadal, though often confused with tsunamis, arises from distant storm-generated waves, contrasting with tsunamis triggered by underwater disturbances, typically seismic activities.
    • Clarification: Understanding this distinction is crucial for implementing effective early warning systems and mitigating the impact of coastal hazards.

    PYQ:

    2017: At one of the places in India, if you stand on the seashore and watch the sea, you will find that the sea water recedes from the shore line a few kilometres and comes back to the shore, twice a day, and you can actually walk on the sea floor when the water recedes. This unique phenomenon is seen at-

    (a) Bhavnagar

    (b) Bheemunipatnam

    (c) Chandipur

    (d) Nagapattinam

     

    Practice MCQ:

    The Coastal areas of Kerala recently witnessed the Oceanic Swell Waves locally known as Kallakkadal. In this regard consider the following statements:

    1.    Kallakkadal typically occurs during the spring season (March-April).

    2.    These waves stem from distant storms in the southern Indian Ocean.

    Which of the given statements is/are NOT correct?

    (a) Only 1

    (b) Only 2

    (c) Both 1 and 2

    (d) Neither 1 nor 2

  • Places in news: Afanasy Nikitin Seamount

    Why in the news?

    • India has applied to the International Seabed Authority (ISBA) for exploration rights in the Afanasy Nikitin (AN) Seamount in the Indian Ocean outside its jurisdiction.
    • India’s application is motivated by reports of Chinese vessels conducting reconnaissance in the same region, raising concerns about strategic interests and resource competition.

    About International Seabed Authority (ISBA)

     

    • The ISBA is an intergovernmental organization established under the United Nations Convention on the Law of the Sea (UNCLOS).
    • It was established in 1994 and headquartered in Kingston, Jamaica.
    • ISA is tasked with regulating mineral-related activities in the international seabed area beyond national jurisdiction, which includes polymetallic nodules, polymetallic sulphides, and cobalt-rich ferromanganese crusts.
    • The Authority issues exploration and exploitation contracts to countries and private entities for deep-sea mining activities, subject to certain regulations and environmental safeguards.
    • ISA comprises various organs, including the Assembly, the Council, the Legal and Technical Commission, and the Secretariat, each with specific functions related to deep-sea mining regulation.
    • According to Article 156(2) of the UNCLOS, all UNCLOS parties are members of ISBA.
    • As of 2023 has 169 members, including 168 member states and the European Union.
    • India became a member of the UNCLOS in 1994.

     

    About AN Seamount

    • The AN Seamount, located about 3,000 km from India’s coast, is a substantial structural feature in the Central Indian Ocean Basin.
    • A seamount is a large submarine landform that rises from the ocean floor without reaching the surface, and thus is not an island.
    • It is 400 km-long and 150 km-wide. From an oceanic depth of about 4,800 metres it rises to about 1,200 metres.
    • It was discovered during a marine research expedition, named after the Russian explorer Afanasy Nikitin.
    • It is renowned for its polymetallic nodules containing cobalt, nickel, manganese, and copper

    Continental Shelf Claims and Implications

    • Sri Lanka has applied for continental shelf claims up to 500 nautical miles beyond its Exclusive Economic Zone (EEZ), citing a special provision.
    • India, noting Chinese presence, has staked a claim for exploration rights to prevent future consequences.
    • India has also applied for permission to explore another region, spanning 3,00,000 square km, called the Carlsberg Ridge in the Central Indian Ocean to investigate for polymetallic sulphides, which are reportedly rich in copper, zinc, gold and silver.

    PYQ:

    2021: Consider the following statements:​

    1. The Global Ocean Commission grants licences for seabed exploration and mining in international waters.​
    2. India has received licences for seabed mineral exploration in international waters.​
    3. ‘Rare earth minerals’ are present on seafloor in international waters.​

    Which of the statements given above are correct?​

    a)    1 and 2 only ​

    b)    2 and 3 only​

    c)    1 and 3 only ​

    d)    1, 2 and 3​

     

    Practice MCQ:

    Consider the following statements about the International Seabed Authority (ISBA):

    1. ISBA is an intergovernmental organization established under the United Nations Convention on the Law of the Sea (UNCLOS).
    2. All UN members are naturally parties to the ISBA.

    Which of the given statements is/are correct?

    a)    Only 1

    b)    Only 2

    c)    Both 1 and 2

    d)    Neither 1 nor 2

  • Karnataka approaches Supreme Court over NDRF Funds for Drought Management

    What is the news?

    • The Karnataka government has approached the Supreme Court against the Union government, seeking the release of drought relief funds from the National Disaster Response Fund (NDRF).
    • This disagreement marks the second major dispute after alleged ‘injustice’ in tax devolution and other allocations.

    Extent of Drought and Water Scarcity in Karnataka

    • Rainfall Deficit: During the last monsoon season, Karnataka experienced significant rainfall deficits, exacerbating the drought situation and affecting agricultural productivity.
    • Drought conditions: Karnataka faces extensive drought conditions, with 223 out of 236 taluks (mandals) declared as drought-hit areas, resulting in substantial crop loss.
    • Compensation Sought: The state has sought substantial financial assistance from the Centre, amounting to Rs 18,171 crores, to address the damages caused by drought.

    Karnataka’s Writ Petition to the Supreme Court

     

    • Legal Action: Karnataka’s petition under Article 32 of the Constitution seeks relief against the Union government’s alleged inaction in providing financial assistance for drought management.
    • Basis of Petition: The petition argues that the delay in releasing funds violates fundamental rights guaranteed under Articles 14 and 21 of the Constitution, pertaining to equality before the law and protection of life and personal liberty.

     

    What is National Disaster Response Fund (NDRF)?

    • The NDRF is a statutory body constituted under the Disaster Management Act, 2005.
    • It supplements State Disaster Response Fund (SDRF) of a State, in case of a disaster of severe nature, provided adequate funds are not available in SDRF.
    • The July 2015 guidelines states that natural calamities of cyclone, drought, earthquake, fire, flood, tsunami, hailstorm, landslide, avalanche, cloud burst, pest attack and cold wave and frost will qualify for immediate relief assistance from NDRF.
    • NDRF is managed in the “Public Accounts” under “Reserve Funds not bearing interest”.
    • The Comptroller and Auditor General of India (CAG) audits the accounts of NDRF.

    Disaster Relief for Indian states

    • Under the 2005 Disaster Management Act, there is no definition of disasters.
    • It can include any event arising from natural or man-made causes that can severely disrupt life for people, going beyond their coping capacity.
    • The 15th Finance Commission introduced a new methodology for state-wise allocations, considering factors like past expenditure, risk exposure, hazard, and vulnerability.

    Institutional Mechanism

    • States have the State Disaster Relief Funds (SDRF).
    • The Centre contributes 75% of the funds (and 90% for Himalayan and NE states) and states contribute the remainder.
    • The total amount is decided as part of the budgetary allocations and released periodically by the Centre.

    In case a state needs the Centre’s assistance, it must follow a procedure:

    1. It should detail the extent of the damage in a memorandum and submit it
    2. If this is acknowledged by Centre, an Inter-Ministerial Central Team (IMCT) conducts on-ground inspections to survey the damage
    3. A National Executive Team analyses the IMCT report
    4. Based on its recommendations, a High Level Committee shall approve the release of immediate relief from NDRF.

    Additionally, the Union Ministry of Home Affairs oversees the utilisation of NDRF releases.

     

    PYQ:

    2014: Drought has been recognized as a disaster in view of its spatial expanse, temporal duration, slow onset and lasting effects on vulnerable sections. With a focus on the September 2010 guidelines from the National Disaster Management Authority (NDMA), discuss the mechanisms for preparedness to deal with likely El Nino and La Nina fallouts in India.

     

    Practice MCQ:

    Consider the following statements about National Disaster response fund (NDRF):

    1. NDRF is a part of consolidated fund of India.
    2. Comptroller and Auditor General of India (CAG) audits the accounts of NDRF.

    Which among the above statements is/are correct?

    1. Only 1
    2. Only 2
    3. Both 1 and 2
    4. Neither 1 nor 2

  • Subduction Zone discovered beneath Gibraltar Strait

    What is the news?

    • Scientists in Portugal have uncovered a concerning revelation about the fate of the Atlantic Ocean, highlighting a potential ‘Ring of Fire’ (a Subduction Zone).
    • Researchers caution that the Atlantic may be on the brink of closure due to subduction activity.

    Why discuss this?

     

    • Closure of Gibraltar Strait: Computer simulations project the subduction zone’s expansion over the next 20 million years, forming the ‘Ring of Fire’ in the Atlantic leading to the closure of Gibraltar Strait.
    • Geological Parallel: This process mirrors the Pacific Ocean’s Ring of Fire, reshaping the ocean basin through gradual subduction of the ocean floor beneath continents.

     

    About Gibraltar Strait

    Details
    Location
    • Connects the Atlantic Ocean to the Mediterranean Sea;
    • Separating the southern tip of the Iberian Peninsula of Europe from the northern coast of Africa.
    Width Approximately 13 km (8.1 miles) at its narrowest point.
    Depth Varies, with the deepest point reaching around 300 meters (984 feet).
    Formation
    • Convergence point for the Eurasian Plate and the African Plate.
    • Formed around 5.33 million years ago during the Messinian salinity crisis when the Atlantic Ocean breached the barrier separating it from the Mediterranean Sea, resulting in a catastrophic flood known as the Zanclean flood.
    • The strait’s current shape and depth were further influenced by tectonic movements and erosional processes over geological time.
    Historical Significance Serves as a key maritime passage for trade and military purposes.
    Disputes
    • Subject of contention between Spain and the United Kingdom;
    • Gibraltar Overseas Territory under British control.

     

    What are Subduction Zones?

    • Subduction zones occur at convergent plate boundaries, where two tectonic plates move toward each other.
    • This convergence is often between an oceanic plate and a continental plate or between two oceanic plates.
    • Subduction Process:
    1. Collision of Tectonic Plates: When two tectonic plates collide, the denser oceanic plate is forced beneath the less dense continental plate or another oceanic plate.
    2. Partial Melting: As the oceanic plate descends into the mantle, it generates intense heat and pressure, causing partial melting of the mantle material.
    3. Volcanic Activity: The molten material formed by the subduction process rises through the Earth’s crust, leading to volcanic eruptions at the surface.
    4. Formation of Volcanic Arcs: These eruptions often occur in chains known as volcanic arcs, which parallel the subduction zone. Ex. Andes in S. America; Cascade Range in North America.

    Implications of this Activity

    • Earthquakes: Subduction zone earthquakes can be particularly destructive and may trigger tsunamis due to the displacement of large volumes of water.
    • Trench Formation: The surface expression of a subduction zone is often a deep oceanic trench, where the descending plate bends and plunges into the mantle.
    • Mountain Building: Over time, the continuous subduction of oceanic crust can lead to the uplift and deformation of the overriding plate, resulting in the formation of mountain ranges adjacent to the subduction zone. These mountains may exhibit complex geological structures, including folds and faults.
    • Recycling of Oceanic Crust: As oceanic plates are subducted, they are gradually consumed by the mantle, releasing minerals and elements that are eventually returned to the surface through volcanic activity.

    PYQ:

    2010: Which one of the following can one come across if one travels through the Strait of Malacca?

    1. Bali
    2. Brunei
    3. Java
    4. Singapore

     

    2011: Between India and East Asia, the navigation time and distance can be greatly reduced by which of the following?

    1. Deepening the Malacca straits between Malaysia and Indonesia.
    2. Opening a new canal across the Kra Isthmus between the Gulf of Siam and Andaman sea.

    Which of the statements given above is/are correct?

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2

     

    Practice MCQ:

    Which of the given statement about the Gibraltar Strait is NOT correct?

    1. It connects the Atlantic Ocean to the Mediterranean Sea.
    2. It is approximately 13 kilometers wide at its narrowest point.
    3. The deepest point of the Gibraltar Strait reaches around 300 meters.
    4. It was formed around 5.33 million years ago during the Holocene Epoch due to tectonic movements.

  • Geo-Heritage Sites in India

    Why in the news

    • Pandavula Gutta, an ancient geological marvel predating the Himalayan hills, has been officially designated as Telangana’s sole Geo-heritage site.
    • Also the 165 million-year-old meteor Ramgarh Crater in Rajasthan was declared geo-heritage site.

    [A] Pandavula Gutta

    • Pandavula Gutta is located in Jayashankar Bhupalpally District in Telangana.
    • It is known for its rock art and geological heritage.
    • The site features Paleolithic cave paintings depicting wildlife and symbols.
    • Discovered in 1990, it showcases habitation from the mesolithic to medieval times.
    • Recognized as the sole Geo-heritage site in Telangana, older than the Himalayan hills.

     

    [B] Ramgarh Crater

    • The Ramgarh Crater, also known as Ramgarh structure, Ramgarh Dome, and Ramgarh astrobleme, is a meteor impact crater located near the town of Ramgarh in Baran district of Rajasthan.
    • It is established as an asteroid impact crater in India, excavated within sandstone, shale, and limestone horizons of the Lower Bhander Group of the Vindhyan Region.
    • It was formed by a meteorite impact, with a diameter of 3.2 kilometers and an elevation of over 200 meters above the surrounding terrain.
    • It is declared Conservation Reserve, namely Ramgarh Conservation Reserve, under the Wildlife (Protection) Act, 1972 and a notified wetland under Wetland (Conservation & Management) Rules, 2017.

     

    What are Geo-Heritage Sites?

    • Geo-Heritage Sites in India are geological features of significant importance, either culturally or inherently, that provide insights into the Earth’s evolution or serve educational purposes.
    • These sites are recognized and protected by the Geological Survey of India (GSI) and the respective State governments.
    • India presently has 34 National Geological Heritage Monument Sites.
    • Examples:
      1. Mawmluh Cave in Meghalaya
      2. Majuli Island in Assam
      3. Chabimura in Tripura
    • Purpose:
      1. Promote geotourism
      2. Preserve unique geological formations
      3. Enhance geological literacy among the public

     

    Tap this link to read more about all Geo-Heritage Parks in India:

    https://vikaspedia.in/education/childrens-corner/geological-heritage-sites-of-india

    PYQ:

    Q.Which one of the following statements is correct?​ (2021)

    1. Ajanta Caves lie in the gorge of Waghora River.​
    2. Sanchi Stupa lies in the gorge of Chambal River.​
    3. Pandu-Lena Cave Shrines lie in the gorge of Narmada River.​
    4. Amaravati Stupa lies in the gorge of Godavari River.​

    Practice MCQ:

    Which of the given statements about the Ramgarh Structure is NOT correct?

    1. It is an asteroid impact crater.
    2. It is located in the Deccan Plateau.
    3. It is a notified wetland under Wetland (Conservation & Management) Rules, 2017.
    4. It is under Conservation Reserve under the Wildlife (Protection) Act, 1972.

  • Atmospheric Research Testbed in Central India (ART-CI)

    Why in the news-

    • The Ministry of Earth Sciences has commissioned Atmospheric Research Testbed-Central India (ART-CI) near Bhopal.

    About Atmospheric Research Testbed

    • ART-CI stands as an innovative testbed facility, pioneering the exploration of monsoon convection and land-atmosphere interactions, marking a significant advancement in climate research.
    • The Indian Institute of Tropical Meteorology (IITM), Pune leads ART-CI, operating under the Ministry of Earth Sciences (MoES).

    Mission Objectives

    • ART-CI primarily targets the monsoon trough area, encompassing the Monsoon Core Zone (MCZ), a critical component of the regional climate system.
    • Understanding this zone is paramount for precise weather forecasts and accurate climate modelling within India.

    Monsoon Core Zone (MCZ)

     

    • MCZ is a region in India stretching from Gujarat to West Bengal in the east.
    • India Meteorological Department demarcates it as an agricultural region where cropping is mostly rainfed.
    • It is the region within the monsoon trough area that plays a central role in the dynamics of the Indian monsoon system.
    • It is characterized by intense convective activity, significant rainfall, and crucial atmospheric interactions that influence the overall behavior of the monsoon.
    • The MCZ typically experiences a concentration of atmospheric processes that drive the onset, progression, and withdrawal of the monsoon rains across the Indian subcontinent.

    Features and Capabilities

    • ART-CI’s development unfolds incrementally as part of the Atmosphere & Climate Research-Modelling Observing Systems & Services (ACROSS) umbrella scheme.
    • The facility will feature an extensive array of remote-sensing and in-situ instruments.
    • These tools would help monitoring of various atmospheric parameters like convection, cloud cover, precipitation, soil moisture, radiation levels, and microphysics.

  • In news: Popocatepetl Volcano

    In the news

    • Popocatepetl, Mexico’s most dangerous active volcano has erupted 13 times in the past day, hurling columns of ash and smoke into the sky.

    About Popocatepetl Volcano

    • Popocatepetl — which means “Smoking Mountain” in the Aztec Nahuatl language — is located in central Mexico roughly 72 km southeast of Mexico City.
    • Popocatepetl is situated in the eastern half of the Trans-Mexican Volcanic Belt, in Central Mexico.
    • It lies on the border between the states of Puebla and Morelos.
    • The summit of Popocatepetl stands at an elevation of about 5,426 meters above sea level, making it the second-highest peak in Mexico after Citlaltepetl (Pico de Orizaba).

    Geological Details

    • Popocatepetl is a stratovolcano (composite volcano) characterized by its steep, conical shape built up by successive layers of volcanic ash, lava flows, and pyroclastic materials.
    • It is one of Mexico’s most active volcanoes, with documented eruptions dating back to the 14th century.
    • In the modern era, significant eruptions have occurred in 1947, 1994, 2000, 2005, and ongoing activity since 2013.
    • The volcano’s eruptions are primarily andesitic to dacitic in composition, characterized by the eruption of viscous lava flows and explosive eruptions producing ash clouds, pyroclastic flows, and lahars (mudflows).

    Try this PYQ from CSE Mains 2021

    Q. Mention the global occurrence of volcanic eruptions in 2021 and their impact on regional environment.

  • Scientists vote down Declaration of Anthropocene Epoch

    In the news

    • The proposal to declare the start of the Anthropocene Epoch, signifying the impact of human activity on Earth’s geological history, has sparked debate among scientists.
    • Despite mounting evidence of human-induced changes to the planet, a recent vote by a scientific committee has rejected the notion.

    Understanding Geological Time

    • Geologic Time Scale: Geoscientists use the Geologic Time Scale (GTS) to measure Earth’s history, categorizing it into aeons, eras, periods, epochs, and ages.
    • Chronostratigraphic Classification: The GTS is based on chronostratigraphic units, marked by significant geological events, shaping the planet’s conditions.

    The Proposed ‘Human Epoch’

    • Holocene Epoch: The Holocene began approximately 11,700 years ago, following the Last Glacial Period, coinciding with the rise of human civilization.
    • Anthropocene Proposal: The Anthropocene concept suggests that human activities have altered Earth significantly, warranting recognition as a distinct geological epoch.

    Understanding the Anthropocene Epoch

    • Coined Term: The Anthropocene epoch was first coined by Nobel Prize-winning chemist Paul Crutzen and biology professor Eugene Stoermer in 2000.
    • Human Impact: The Anthropocene represents the geological time interval characterized by radical changes in the Earth’s ecosystem due to human impact, particularly since the onset of the Industrial Revolution.
    • Environmental Changes: Numerous phenomena associated with the Anthropocene include global warming, sea-level rise, ocean acidification, mass-scale soil erosion, deadly heat waves, and environmental deterioration.
    • Geological Strata: The AWG’s website states that these changes are reflected in a distinctive body of geological strata, with the potential to be preserved into the far future.

    Rejection of the Proposal

    • Scientific Deliberations: Despite the Anthropocene Working Group’s proposal, the Subcommission on Quaternary Stratigraphy voted against declaring the Anthropocene epoch.
    • Criticism and Concerns: Critics argue against defining the Anthropocene based on recent events, questioning the significance of the proposed start date and the boundary between epochs.

    Geological Implications

    • Definition of Epochs: The rejection highlights the challenge of defining geological epochs based on human-induced changes, given the traditional criteria for epoch delineation.
    • Permanence and Recognition: While the vote does not negate human impact on the planet, it raises questions about the formal recognition of the Anthropocene as a distinct epoch.

    Future of the Anthropocene Concept

    • Beyond Epochs: Some scientists propose viewing the Anthropocene as an “event” rather than a formal epoch, acknowledging its transformative nature without conforming to traditional geological classifications.
    • Relevance and Recognition: Regardless of formal classification, the concept of the Anthropocene underscores the profound impact of human activity on Earth’s systems, shaping discussions on environmental stewardship and sustainability.

    Back2Basics: Geological Time Scale

    • The Geological Time Scale is a system used by geologists and palaeontologists to divide Earth’s history into distinct time intervals based on significant geological and biological events.
    • It provides a framework for organizing and understanding the vast expanse of time since the formation of the Earth, approximately 4.6 billion years ago, up to the present day.
    • The Scale is divided into several hierarchical units, including eons, eras, periods, epochs, and ages.

    Here is a simplified overview of the major divisions:

    (1) Eon: The largest division of time on the Geological Time Scale. The history of Earth is typically divided into four eons:

    • Hadean Eon: Represents the earliest stage of Earth’s history, from its formation to around 4 billion years ago.
    • Archean Eon: Covers the period from around 4 billion to 2.5 billion years ago. It includes the formation of the Earth’s crust, the emergence of life, and the development of the first continents.
    • Proterozoic Eon: Encompasses the time between 2.5 billion and 541 million years ago. It includes significant evolutionary developments, such as the emergence of complex multicellular life.
    • Phanerozoic Eon: The current eon, spanning from 541 million years ago to the present. It is further divided into eras.

    (2) Era: The second-largest division of time, encompassing longer periods of geological history within an eon. The Phanerozoic Eon is divided into three eras:

    • Paleozoic Era: Covers the time from 541 million to 252 million years ago. It is known for the diversification of life, including the appearance of complex marine organisms, fish, insects, and the first terrestrial plants.
    • Mesozoic Era: Spans from 252 million to 66 million years ago. It is often referred to as the “Age of Reptiles” and includes the dominance of dinosaurs, as well as the rise of mammals and birds.
    • Cenozoic Era: Extends from 66 million years ago to the present. It is sometimes called the “Age of Mammals” and includes the diversification and proliferation of mammals, the appearance of humans, and the development of modern ecosystems.

    (3) Period: A subdivision of an era, representing a distinct interval of time characterized by specific geological and biological events. For example:

    • The Paleozoic Era is divided into periods such as the Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian.
    • The Mesozoic Era is divided into periods including the Triassic, Jurassic, and Cretaceous.
    • The Cenozoic Era is divided into periods such as the Paleogene, Neogene, and Quaternary.

    (4) Epoch: A smaller subdivision of a period, representing a shorter interval of time. Epochs are defined by more localized geological and biological changes.

    (5) Age: The smallest division of time on the Geological Time Scale. Ages represent relatively brief periods, often defined by specific fossil or rock layers.

  • Singhbhum Craton: Insights from the Archaean Age

    Why in the News?

    • Some recent study about the Singhbhum Craton in India, reveals that explosive volcanic eruptions were frequent around 3.5 billion years ago in regions that are also present in South Africa, and Australia.

    What are Cratons?

    • Cratons are stable, ancient portions of the continental lithosphere, consisting of Earth’s two topmost layers—the crust and the uppermost mantle.
    • Cratons are typically found in the interiors of tectonic plates and are characterized by their ancient crystalline basement rock, often dating back to the Archean Eon.
    • Mantle plume events have played a significant role in the evolution of cratons.

    About Singhbhum Craton:

    • The Singhbhum Craton is a geological region in India.
    • Location: It is located in eastern India, covering parts of the states of Jharkhand, Odisha, and West Bengal. The craton is separated from the Bastar Craton by the Mahanadi Graben and is in the vicinity of two Proterozoic mobile belts: the Satpura Mobile Belt and the Eastern Ghat Mobile Belt.
    • Geological features:
      • The rocks in the Singhbhum Craton are predominantly of Archean age, ranging from Paleoarchean to Paleoproterozoic.
      • It is a part of the larger Indian Shield, which is a stable continental crust that formed during the Archean Eon.
      • The Singhbhum Craton is known for its abundant occurrences of Banded Iron Formations (BIFs), which are closely associated with basic volcanic and ultrabasic intrusive. The craton is also known for its iron ore deposits, which are found in the Iron Ore Group (IOG) and are closely associated with lavas and tuffs.
      • The Singhbhum Craton has undergone regional metamorphism of the amphibolite facies and is believed to have evolved as a consequence of multiple phases of compressive deformation.
      • The craton is made up of multiple pulses of discrete mantle plume events, resulting in a complex geological history.

    Archaean Eon

    • The Archaean Eon, one of the two formal divisions of Precambrian time, began about 4 billion years ago and extended to the start of the Proterozoic Eon.
    • During this period, life on Earth was limited to simple single-celled organisms lacking nuclei, known as Prokaryota.
    • The atmosphere lacked oxygen, and the Earth’s crust had cooled enough to allow the formation of continents.
    • Volcanic activity was considerably higher than today, with numerous lava eruptions.
    • The oldest rock formations exposed on Earth are from the Archaean Eon.
    • The Archaean rock system includes Archaean Gneisses and Schists, which are the oldest metamorphosed rocks found in abundance in regions like the Dharwar district of Karnataka.

    What are the recent key findings?

    • Submarine Mafic Volcanism: The prevalence of submarine mafic volcanic eruptions between 3.5 and 3.3 billion years ago is documented, enriching our understanding of ancient volcanic and sedimentary processes.
    • Geodynamic Insights: Comparative analysis enhances our comprehension of early Earth tectonic activities and surface/atmospheric processes during the Archaean.

    Research Methodology Used:

    • Field Studies and Radiometric Dating: Detailed field-based studies coupled with uranium-lead radiometric-age dating were employed to establish geological timelines and understand magma crystallization.
    • Comparative Analysis: The geological similarities between the Singhbhum Craton and counterparts in South Africa and Australia were studied, focusing on volcanic eruption patterns.

    Implications and Significance of the study:

    • Earth’s Formative Years: Insights into Earth’s early tectonic activities contribute significantly to understanding the planet’s formative years.
    • Habitable Conditions: Unique geological features, such as greenstone belts, provide invaluable information about early habitable conditions and the emergence of life.
    • Global Geodynamic Processes: Comparative studies across cratons worldwide facilitate the construction of comprehensive models elucidating ancient geodynamic processes prevalent during the Archaean.

  • What is Humboldt’s Enigma and What does it mean for India?

    Humboldt’s Enigma

    Introduction

    • The question of where biodiversity is concentrated has intrigued explorers and naturalists for centuries. Humboldt has tried to answer this question.

    Humboldt’s Insights

    • Alexander von Humboldt: A polymath of the 18th century, Humboldt recorded diverse natural observations, proposing a relationship between temperature, altitude, humidity, and species distribution.
    • Mountain Exploration: During his exploration of South America, Humboldt studied plant distribution on mountains, noting variations with elevation.
    • Chimborazo Mountain: Humboldt used Chimborazo Mountain in Ecuador as an example, illustrating the concept of mountain diversity.

    What is Humboldt’s Enigma?

    • Sun’s Energy: Tropical areas receive more solar energy, fostering greater primary productivity and biodiversity due to the availability of ecological niches.
    • Mountain Exception: Mountains, despite being outside the tropics, have been an exception to the rule, posing Humboldt’s enigma.

    Biodiversity Drivers

    • Earth’s History, Geography, and Climate: These factors are the primary drivers of mountain diversity.
    • Geological Processes: Mountains serve as ‘cradles’ for new species due to geological processes like uplifts, creating new habitats.
    • Climatic Stability: Climatologically stable mountains act as ‘museums,’ preserving species over time.
    • Coastal Tropical Sky Islands: Examples like the Shola Sky Islands in the Western Ghats exhibit both cradle and museum characteristics.

    Eastern Himalaya: An Anomaly

    • Diversity Beyond Tropics: Eastern Himalaya boasts exceptional diversity, challenging the conventional tropical biodiversity paradigm.
    • Multiple Factors: Climate dissimilarity and geological heterogeneity contribute to high biodiversity.
    • Climate Variability: Different temperature and rainfall levels on the same mountain support diverse biomes.

    Unresolved Questions

    • Complexity of Biodiversity: Numerous factors drive diversification and Humboldt’s enigma in different regions, leading to over a hundred hypotheses.
    • Data Limitations: Fine-scale species occurrence data are lacking, hindering precise explanations.
    • Call for Research: India’s under-studied areas need more extensive research, including the use of genetics, to understand true biodiversity.
    • National Initiatives: Programs like the National Mission on Himalayan Studies and Biodiversity need strengthening to support basic research.

    Conclusion

    • Humboldt’s enigma represents one facet of mountain biodiversity, offering opportunities for study and insights into global climate and landscape change issues.