Interior of Earth Current Affairs - 2019

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Key Facts: Deep Carbon Observatory

The Deep Carbon Observatory (DCO) is a global research program to outreach carbons role on Earth. It is a community of scientists including physicists, biologists, geo – scientists and chemists working across several traditional disciplinary lines.

Key highlights of DCO research

  • It has found that there are ultra – deep diamonds at 670 km depth in the mantle. It has signatures of geochemical signature of organic material from Earth’s surface.
  • There may be significant amounts of iron carbide in the Earth’s core that accounts to two – thirds of Earth’s carbon
  • It has identified abiogenic sources of methane from crust and mantle. Abiogenesis is a hypothetical theory which proposes that fossil fuels are formed from inorganic matter rather than by decomposition of organisms or organic matter.
  • The complex links between biosphere and geosphere and their evolution. The links are reflected in major events like Great Oxidation Event
    • Great Oxidation Event – Around 2.4 billion years ago, biologically induced molecular oxygen accumulated in the Earth’s atmosphere. This changed the atmosphere to an oxidizing atmosphere from a weak reducing atmosphere. The even caused almost all lives on the Earth to go extinct. Scientists are still unable to determine causes of the event.
  • The Volcanic flux of carbon – dioxide is twice as that of previously determined.

DCO Explorations

The DCO explores

  • High pressure and Extreme temperature organic synthesis
  • Complex interactions between organic molecules and minerals
  • Conducts field observations of deep microbial eco systems
  • Constructs theoretical models of lower crust and upper mantle carbon sources
  • Conducts observations of anomalies in petroleum geochemistry

Reservoir and Flux community of DCO

The subduction of tectonic plates and volcanic outgassing are the main sources of carbon fluxes. But the process and rates of these carbon fluxes are poorly understood. The main function of the Reservoir and Flux community of DCO is to explore the storage and transport of carbon in the deep interior of the Earth.

The Deep Earth Carbon Degassing Project of DCO is examining if large reservoirs of carbon are hidden in the mantle and core. It also works on finding how this carbon outgasses from the Earth’s deep interior into the surface environment.

Deep Energy wing of DCO

It quantifies the processes and environmental conditions that control origins, forms, quantities and movements of carbon compounds. This community of DCO predominantly works around carbon compounds that were reduced from deep carbon compounds through geologic time.

It conducts investigations in 25 global terrestrial and marine environment to determine the processes controlling movements of abiotic gases and their origin, form, quantities. It also discriminates abiotic and biotic methane gas and organic species.

The Deep Energy community also quantifies the rates of fluid rock interactions that produce abiotic hydrogen.

Deep life wing of DCO

It documents the interaction between the carbon cycle and diversity of Earth’s deep biosphere. It marks the diversity of subsurface marine and continental microorganisms in space and time and their interaction with the deep carbon.

The wing conducts Census of Deep life annually. This census identifies the diversity and distribution of microbial life in continental and marine deep subsurface environments.

According to the 2018 census by the Deep life wing of DCO, life forms on the earth including 70% of bacteria comprises up to 23 billion tons of carbon. They live up to 4.8 km deep underground including 2.5 km below the seabed.

Silicon identified as ‘missing element’ in Earth’s core

Scientists from Tohoku University in Japan have claimed that Silicon (Si) is the ‘missing element’ in the Earth’s core. This discovery could help us to better understand how our world formed.

According to them silicon likely makes up a significant proportion of Earth’s core after its major constituents iron and nickel. It was missing element in the deep interiors of our planet that has eluded us for decades.

Key Facts
  • It was found that silicon is a major element and constitutes about 5% of the Earth’s inner core by weight. It could be dissolved into the iron-nickel alloys.
  • For the study, scientists recreated the high temperatures and pressures found in the deep interior of the Earth’s core. They recreated alloys of iron and nickel and mixed them with silicon.
  • They then subjected these alloys to the immense pressures and temperatures that exist in the inner core.
  • Scientists discovered that this mixture matched what was seen in the Earth’s interior with seismic data.

Note: The innermost part of Earth i.e. core is thought to be a solid ball with a radius of about 1,200 kilometres. It is far too deep to investigate directly, so scientists study this region’s make-up using seismic wave. Earth’s core is mainly composed of iron (makes up about 85% of its weight) and nickel (accounts for about 10% of the core).