A recent study reveals that Deccan Volcanism, despite its catastrophic effects on terrestrial fauna such as the extinction of dinosaurs, caused only regional and short-term impacts on tropical flora.
Key Findings of the Study
- Minimal Impact on Tropical Flora: Deccan Volcanism had limited negative effects on tropical flora, with impacts being regional and short-term.
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- Tropical Flora: Plant life characteristic of tropical regions, known for its incredible diversity, lushness, and abundance
- Examples include rainforests, mangroves, and savannas.
- Angiosperms: Flowering plants that produce seeds enclosed within a fruit.
- They are the most diverse group of plants, dominating most terrestrial ecosystems. Examples include roses, orchids, and oak trees.
- Gymnosperms: Seed-bearing plants that do not produce flowers or fruits.
- Their seeds are typically borne on the surface of cones. Examples include pine trees, cycads, and ginkgoes.
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- Positive Influence on Angiosperm Development: The volcanic activity indirectly supported the development of diverse tropical flora.
- It eliminated large faunal communities like dinosaurs and gymnosperms, creating undisturbed, fertile habitats.
- The warm and humid climate during dormant volcanic phases provided ideal conditions for angiosperms to grow and diversify.
- Resilience of Tropical Flora: Despite the release of toxic greenhouse gases that contributed to the Cretaceous-Paleogene (K-Pg) mass extinction, tropical flora displayed high resilience and recovered on a sub-millennial timescale.
- Lessons for Modern Climate Change: The study suggests that tropical rainforests, if left undisturbed, have the potential to recover rapidly under favorable climatic conditions.
Methodology used for the Study
- Sample Collection: Sedimentary rock samples, including mudstone and claystone, were collected from a 17-meter-thick sedimentary sequence in Yeotmal, Maharashtra.
| NLR and CA
The Nearest Living Relative (NLR) approach and Coexistence Approach are two different ways of studying extinct species.
- Nearest Living Relative (NLR) approach: Compares an extinct species to its closest living relative to understand its potential ecology, behavior, and physiology.
- Coexistence Approach: Focuses on understanding the interactions and relationships between extinct species and other species in the same ecosystem to reconstruct the past environment.
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- Palynological Analysis: Pollen, spores, and organic matter were extracted and studied to understand biostratigraphy and reconstruct paleoecology, paleoclimate, and paleobiogeography.
- Analytical Approaches: The Nearest Living Relative (NLR) approach and Coexistence Approach (CA) were used for paleoecological and paleoclimatic modeling.
- Palaeobiogeographic reconstruction was also conducted.
About Deccan Volcanism
- Deccan Volcanism refers to extensive volcanic activity that took place on the Deccan Plateau in India, primarily during the Cretaceous-Paleogene transition, approximately 66 million years ago.
Key Features of Deccan Volcanism
- Formation of the Deccan Traps: Deccan Traps consist of vast, layered flood basalts created by extensive lava flows.
These geological features cover significant portions of central and western India and led to the formation of the Deccan Plateau.
- Reunion Hotspot: The volcanic activity occurred as the Indian Plate migrated northward over the Reunion hotspot, now located at Reunion Island.
- Soil Formation: Weathering of basalt from these eruptions resulted in the creation of Black or Regur soil, known for its fertility.
- Climate Impact: The eruptions released large amounts of greenhouse gases like carbon dioxide and sulfur aerosols.
- This led to significant global climate changes, including global warming and acid rain.
- These climatic disruptions contributed to the extinction of various species, including non-avian dinosaurs.
Mass Extinction Events
Mass extinctions are catastrophic events leading to the rapid and widespread loss of biodiversity on Earth. These events are often triggered by drastic changes in the Earth’s climate, carbon cycle, or catastrophic occurrences such as asteroid impacts or massive volcanic eruptions.
Cretaceous-Paleogene (K-Pg) Extinction
- Occurred 66 million years ago, marking the end of the Mesozoic Era.
- Caused by a massive asteroid impact near the Yucatán Peninsula, Mexico, creating a 120-mile-wide crater.
- Effects:
- Immediate wildfires within 900 miles of impact.
- Global cooling caused by debris and sulfur in the atmosphere.
- Tsunamis and collapse of ecosystems.
- Aggravating Factor: Deccan Volcanic eruptions in India may have amplified climate changes.
- Result: Extinction of 76% of all species, including non-avian dinosaurs.
Major Mass Extinction Events
| Event |
Time (Million Years Ago) |
Cause |
Extinction Rate |
Notable Losses |
| Ordovician-Silurian |
444 |
Glaciation and sea-level fall |
~85% |
Marine species |
| Late Devonian |
375 |
Ocean anoxia and climate change |
~75% |
Reef-building organisms |
| Permian-Triassic |
252 |
Volcanic activity, methane release, climate warming |
~96% |
Marine and terrestrial species |
| Triassic-Jurassic |
201 |
Volcanism and carbon cycle disruptions |
~80% |
Early dinosaurs, marine species |
| Cretaceous-Paleogene |
66 |
Asteroid impact, Deccan volcanism |
~76% |
Non-avian dinosaurs, marine life |
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